HOW TO DIAGNOSE, REPAIR AND UPGRADE YOUR AMPLIFONE AND WELLS-GARDNER COLOR VECTOR (XY) MONITORS
Author: Gregg Woodcock
E-Mail: woodcock@nortel.com
version 6.3 (8-1-96)
Although I have made every effort to be precise, this article may contain errors. Even if it does not, some people may still damage their machines or themselves while using the information found in this document. The author is neither responsible nor liable for any damage or injury resulting from any use of this document. The author makes no guarantees of any kind; USE THIS INFORMATION AT YOUR OWN RISK.
This article is Copyright worldwide 1991, 1996; all rights reserved.
I have gleaned a lot of the information included herein from copyrighted materials released by various entities (a few are even included virtually word for word). The hardware we are discussing is "obsolete" in the sense that it is no longer being made, sold, supplied or repaired by Atari or Wells-Gardner. I have talked to technicians in both companies who, off the record, applauded my efforts and feel that their respective employers couldn't care less about items this old and "useless". In that light, I see my inclusion of this information as "fair use" (not in violation of the "spirit" of copyright law) in the sense that this document may be the only way for many people to repair their equipment.
I apologise in advance to Atari, Wells-Gardner, Star*Tech Journal, and Play Meter for any perceived violation of the "letter" of copyright law.
In sections where I have transcribed documents word for word (indicated by a line of equals sign characters "=..=START=..=" on the top and "=..=STOP=..=" on bottom), text inside square brackets ([]) is my commentary and was not in the original article.
STAR WARS is Copyright (c) 1983 Lucasfilm, Ltd. and Atari, Inc. All rights reserved. Trademark of Lucasfilm, Ltd. used by Atari, Inc. under license.
Reprint permission is conditionally granted to everyone. For publications, the conditions are that (1) I am to be notified before the article is printed, (2) I must be credited and (3) I must be sent a copy of the publication in which this article appears (customary free-lance compensation would be greatly appreciated, too, but is not required). Obviously, publishers/editors will need (and are granted) the right to edit the text; I ask only that it be clearly indicated that the text was abridged or altered (no specifics required). Personal (private) use and distribution is unconditional as long as the ENTIRE text is included (additions are acceptable provided they are clearly marked as such). Fair use applies for all; it is OK, to pull small sections of appropriate text out to be given to people who need it without wasting your time by crediting the source.
I'd like start off by thanking Rick Schieve (rls@intgp1.att.com) for helping me get started in collecting and for donating a file which was the seed for this document.
If this article does not suit your needs, there is probably more technical information (which I have not seen) about vector monitors (of all types) available from Star*Tech including a CD-ROM with 16 years of articles on it!
Star*Tech
Tel: (609) 654-5544
E-MAIL: Invalid
WWW: Invalid
(Anyone have any further info?)
Before you ask, I do have a small cache of spare vector monitor parts ranging from entire monitors, to individual PCBs, to discrete elements (like the HV transformer) for both color and black-and-white units (no Amplifone parts, though; sorry). I am willing to sell or trade so just send me some email or call me at (214) 684-7380. Also, please call me before you junk any vector stuff; I hate talking with operators and hearing, "I threw all that junk in the trash a few weeks/years ago!" If I can't get there to personally take it off your hands, I can make some calls to friends around the world who will be able to. There are quite a few of us nuts who just love these old vector games.
Vector monitors, also referred to by Atari and others as "XY" (ick) or "Quadrascan" (double ick) monitors, are available in black and white or color. A black and white picture tube has one electron gun that lights just one type of phosphor (usually, but not always, white). Color tubes have 3 electron guns that, when the yoke and neck magnets are aligned properly, each hit their own phosphors only, either red, green, or blue (RGB). Something called a shadow mask is used so each gun hits only one set of phosphors. There is no inherent difference between the tubes used in vector monitors and the tubes used in raster monitors; only the control circuitry differs. That is not to say that you can use any tube in any monitor; there are several different neck pinouts that have been used for picture tubes so you have to find a tube with a matching pinout first. If you have a lot of screen burn, you can replace a color vector picture tube with any compatible "off-the-shelf" 100 degree in-line picture tube that is also used in raster-scan displays.
So far, this has been just basic TV stuff and it holds true for raster monitors too. Now we will diverge. The electron guns in the neck of the tube emit a stream of electrons that bombard the face of the tube that would hit dead center if not for the deflection magnets on the neck of the tube. There are two deflection coils. One for horizontal deflection (X) and one for vertical deflection (Y) of the electron beam. Consider the center of the screen to be (0,0) volts to the deflection magnets. If you want to move the beam to the right you put a positive voltage on the horizontal deflection "X" coil (+,0). A negative voltage moves it to the left. Up and down are accomplished with positive or negative voltages to the vertical deflection (Y) coil.
The deflection coils are driven with the same kind of circuitry some audio amplifiers use. Imagine that the game puts out pre-amp analog levels and that the monitor amplifies and displays the output. There are some vector monitors (the ones used in the Cinematronics games) that are digital in nature and have a significantly different design. Do not assume that anything discussed in this document applies to these monitors since much of it does not.
The third section is what (at least by Atari) is called the "Z" amplifier which controls the brightness. There is a "Z" amplifier for each electron gun which means that black and white monitors have only one "Z" amp and color monitors have three.
To draw an asteroid or other object the game shuts off the Z amp (or amps) and applies the correct vector information to the X and Y amplifiers driving the deflection coils to move the beam to the desired location. Then the appropriate Z amp(s) are turned on to illuminate the screen and the vectors are modified to draw an outlined asteroid. On most monitors you can turn the brightness up to the point where the Z amp(s) don't completely shut down and you can see the full path of the electron beam as it flies around. The designers of Star Wars exploited these traces when laying out the dots for the starfield pattern and the Death Star explosion to form "connect-the-dot" messages that say, "MAY THE FORCE BE WITH YOU" on odd waves from 1 to 31 and, "HALLY MARGOLIN RIVERA AVELLAR VICKERS DURFEY" (the last the names of the programmers and other people involved with making the game) on even waves from 2 to 30 and on all waves from 32 to 99.
What I have described so far applies to all vector monitors. Knowing how these things work helps greatly in trouble-shooting. For instance deflection of the beam to the edges of the screen puts the greatest strain on the X/Y deflection circuits so if you monitor has problems at the edges, something is weak in that area. The monitors make their own positive and negative DC from AC inputs so a reasonable thing to check would be the power supplies. One of the main root causes of color vector monitor problems is game lockups causing the monitor to go extended periods with no input signal which fries it in short order. The 2 main problems I have seen for game board lockups are bad solder joints on the inter-board connectors (mainly Tempest) and also noisy power supplies. I suggest that you replace the power supply filter caps with 105 degree Celsius capacitors instead of 85 degree ones; the higher temperature caps last much longer and are more stable.
Vector monitors are also fussy about the quality of certain transistors. The X and Y deflection circuits are very much like audio amplifiers and tend to be hard on the big transistors used in the final stages of amplification. The Atari vectors use a push/pull rearrangement with NPN and PNP transistors for both the horizontal and vertical amps. If you lose one of these transistors, you lose deflection in 1 of 4 directions depending on which transistor goes out.
There is another circuit in the Atari stuff that is very important called the spot killer. What the spot killer does is shut down the Z amp(s) if the X or Y circuits go bad enough to cause the beam to fail to move around the screen enough to keep from burning the phosphors around the zero axes. The phosphors will become permanently damaged if the beam stays in one place for too long. When the spot killer is active a red LED on the deflection board lights. The spot killer also lights if the logic board does not supply the low level X and Y signals for the monitor to amplify or if the voltage supply for amplification is not present so it does not always indicate a monitor failure.
Along these same lines the P324 version of the Wells-Gardner and all Amplifone HV units have a circuit known as the over-voltage protection circuit. This circuit monitors the voltage at pin 4 of the focus assembly. If this voltage increases beyond a tunable threshold, a transistor fires turning off the oscillator. This shuts off the high-voltage power supply and completely kills the picture. It is meant to keep your tubes and other components (such as the high voltage transformer) from being destroyed in the event of a failure causing very large high-voltages.
Atari used 2 different (but pinout compatible) versions of the color vector monitor. The first and most unreliable was the Wells-Gardner. The second (used only in Star Wars and dedicated Major Havoc machines as far as I know) was the Amplifone. There were several versions of the Amplifone, early ones used in Quantum, and later ones used in Star Wars have differing tube/yoke numbers. I'm assuming they are all compatible but don't know for certain? Another quick aside; all the boards and professionally produced documents spell the company name correctly as "Amplifone" but lots of supplemental documentation (such as the document below) misspell it as "Ampliphone". I use whichever spelling was used in the particular document presented.
Each monitor design has a slightly different electrical characteristic and tube shape that will cause games designed for use with the Amplifone to bulge out around the edges (a defect known as "barreling") when using a Wells-Gardner and similarly will cause games designed for use with the Wells-Gardner monitor to cleave inward around the outer edges (a defect known as "pincushioning") when using an Amplifone. It is quite minor and is really only noticeable when in the self-test screen as this draws a (perfectly straight) bounding box around the edge of the display which makes it easy to notice.
The Amplifone uses a neck socket the same as most other (non-vector) monitors from most other manufacturers use but the Wells-Gardner uses a different socket. The pinout, however, is the same so you just need to convert them if you want to switch tubes between the 2 types. If you are careful, you should be able to pull off the plastic neck sockets from the each tube as they are just glued on over the glass. Then just swap them. For example, an Amplifone tube will work in a Wells-Gardner chassis just fine (some versions of the Amplifone manual would lead you to believe they won't but that mistake was corrected in later versions of the manual) except that the display will bulge in the outer-middles slightly. This bulging is due to differences in the yokes and MIGHT be counteracted by swapping the yokes (putting the Wells-Gardner yoke on the transplanted Amplifone tube) but I haven't tried that yet. If you happen to run across a tube cross-reference chart, please let me know what it says about RCA picture tube 19VLUP22 (the Wells-Gardner tube) and Rauland tube M48AAWOOX (the Amplifone tube).
It is pretty easy to check to see if your tube is bad (it doesn't happen a lot but it does happen). Pins are counted counter-clockwise starting at the gap (when looking at the backside of the tube). Pins 9 and 10 are at either end of the heater element. If you want to be absolutely certain about which pin is which, check the socket on your neck board (it should number all the pins). The heater is basically a very low wattage light bulb that emits the electrons which are shot at the phosphor to make light. You should read a short (OK, not a short but a VERY low resistance) across pins 9 and 10 if your heater is OK. If you read an open, your tube is toast and there is nothing you can do (your light bulb is burned out). If your heater is OK, check to make sure that the heater pins are not shorted to any of the emitter cathodes (pins 6, 8, and 11). If you see a short then your tube has a serious problem but in many cases the short can be burned away. Call your local TV repair shop to see if they can "rejuvenate" it.
Here is the complete pinout of the neck/tube.
Here is the complete pinout of the main connector (on the deflection board):
SPECIAL NOTE: The 2nd printing of TM-183 has a typo in Figure 8 on page 11 which incorrectly identifies the heater as existing on pins 5 and 6. Strangely enough, both the 3rd and the 1st printings have the correct numbers; go figure.
I should also mention that the monitor Sega used in it's vector games (Electrohome's G08-CB0) is also an analog monitor and can be used in any Atari vector game (and vice-versa) with the proper adaptors to mate the different wiring harnesses (connectors) plus some circuitry to scale the voltage ranges of the analog signals and the AC supply. I do not have documentation for the G08-CB0 so I cannot say exactly what scaling is required but I can tell you that I have seen G08-CB0 monitors with "Tempest" burned into them and I also saw a Wells-Gardner with "Space Fury" burned into it. I have talked to several people who claim to have seen such a setup in action but they have no specifics. I would appreciate any details anybody can provide about the G08-CB0 and/or the specific conversion details (either direction).
David Shuman <essayes@telerama.lm.com> had this to say about the G08-CB0:
====================START====================
I know this is supposed to be about Atari monitors but here is some information the Sega color vector monitors that I found on page 12 of the November 1981 issue of the Star*Tech journal. I'll include it here just in case you have one of those hybrid setups mentioned above. If anybody knows more about the redesign that is mentioned, please let me know!
Gremlin/Sega reports that all of the problems encountered with the industry's first color X-Y game "Space Fury" have been identified and solved [yeah, right].
The problems are centered around [ack, bad puns, too!] the deflection (X-Y) amps. Under-rated power transistors combined with an extended "on" time during the power-up routine resulted in damaging the amplifier circuit.
The remedy includes a modification to the card cage and replacement of the Electrohome Monitor with a redesigned unit.
Gremlin/Sega will have replaced all defective monitors and modified all game card cages by the end of October.
Initial field fixes did not resolve the problem entirely and Gremlin/Sega decided to undertake the monitor replacement program.
Electrohome, the monitor manufacturer, will replace monitors in the Eastern U.S., while Gremlin/Sega will handle the Western U.S.
For further details contact your distributor.
====================STOP=====================
The Amplifone was commissioned as a replacement to the infamous, failure-prone Wells-Gardner. Unfortunately it had a horrendously unreliable Achilles' heel; the HV transformer. This part is widely (but falsely) believed to be impossible to replace because there are no more HV transformers around. Fortunately, this is incorrect and they are readily available, even though they are a bit expensive.
The replacement HV transformer was over-engineered to the max so that it would not fail as much as the original part and to date Atari reports that THEY HAVE NOT HAD EVEN ONE REPORT OF THE REPLACEMENT EVER FAILING! To be critical, this could be due to the fact that by the time the replacements became available, most people were no longer routing their Star Wars machines (or at least not with the Amplifone monitors in them). Any machines being repaired and used today are likely to get gentle home use which naturally lengthens the life of the monitor and its parts.
If your HV is dead then it is probably either resistor R12 near the HV transformer or the HV transformer itself. CHECK THE RESISTOR FIRST since it is much easier and cheaper to replace. Simply unsolder it and see if it has the proper resistance (2.2K Ohms). You will also want to check to see if the over-voltage protection circuit is misadjusted causing it to activate even though the HV is in a tolerable range. If LED (CR2) is lighted, then the over-voltage protection circuit is activated. If it is on then you either have a misadjusted potentiometer or a damaged HV circuit. Mark the initial position of R19 and tweak it a tiny bit to see if the LED turns off. Don't move it too much or you may damage other parts of the circuit or even your tube if the HV is indeed too high.
The catch is that Atari replacement parts are only supplied at the wholesale level to official Atari game distributors. To find out the distributor closest to you so that you can order this part from them, call Atari at 408.434.3700 and give them you Zip or Area Code and they will give you a business name and phone number. I am pretty sure the MSRP is about $160 but that is significantly cheaper than buying a Wells-Gardner retrofit that you will have to repair about once a year (most distributors discount such old parts below the MSRP so you shouldn't have to pay that much especially if you comparison shop and play the distributors off each other).
Starting with some information I provided to get him started, Tim Tewalt <tewalt@peaks.ENET.dec.com> in mid-1995 attempted to bypass Atari and the distributors by buying factory direct. Here is what he discovered:
====================START====================
"Flyback" Transformer for Amplifone XY monitor
Atari part number: A201005-01
Type number: 926862802 ("Transformer Multiplier")
Manufactured by: WinTron Inc.
Address: 250 Runville Road; Bellefonte, PA 16823
Tel: (814) 355-1521
FAX: (814) 355-1524
[NOTE: The reason for the high prices is that they do not have any stock on hand and would have to retool the machinery to manufacture a fresh batch. Perhaps it would be simpler and cheaper to get the spec from them and find out what it would cost to have a professional wire one up by hand...]
====================STOP=====================
If your HV transformer is dead then you will need to order Atari part number A201005-01. This part was available in inexhaustible quantities from Atari until recently but now Atari claims they have no more. I suspect that with all the reorganizations of the company some of the "dead weight" inventory was liquidated or thrown out altogether. If you make enough phone calls to large distributors, you should be able to locate one. If you do, please let me know and I'll add the information to this document. One person reported that when his HV transformer went bad it took VR1, R20, and CR5 with it so you may want to test/replace these parts, too (they are commonly available).
Here is the document that describes how to install an Amplifone HV transformer. Thanks to Keith Jarett (keith@tcs.com) for mailing me a photocopy (who in turn wishes to thank Mark Sherman and Al Vernon of Atari Games for their fabulous in-depth knowledge and tech support. I agree; these guys have helped me a few times, too, and are fantastic).
====================START====================
[NOTE: To my knowledge, Atari never bothered to copyright these instructions and they are not marked with a copyright symbol.] INSTALLING THE NEW AMPLIPHONE [sic] HIGH VOLTAGE TRANSFORMER
[NOTE: End of document; here is further advice from the Atari techs...]
After you finish, you will need to adjust brightness (bottom pot on the white module). Use the self test screen for this. Also adjust focus. If nothing happens, the other (lower) focus wire is broken like mine was [NOTE: Mine was broken, too!]. Take off the rubber cap to verify. Focus is the top pot on the white module. This connection is fragile and takes a lot of heat/current so it frequently breaks off.
Adjust R7 (the frequency of the primary switching) to get a video B+ of 180 volts. According to Mark, this will give the correct HV. You don't really need to tweak R17 as described in the manual if you know that your over-voltage protection cutoff is working OK. Recheck focus after tweaking R7.
If any problems occur, verify that the +24 and -24 volt regulators are reasonably close to the correct output voltages. Some departure is OK if you have the 5 watt resistors bridging their inputs and outputs (these are present to relieve the load under transient conditions such as the all-white death star explosion).
The board should now run MUCH cooler. I can comfortably touch all the HV heat sinks which was not true before.
====================STOP=====================
One word of caution about replacing the HV transistor (note that I said "transistor", NOT "transformer"; we are shifting gears); double check the part that you receive BEFORE you install it. Why? Here is a transcription of a note I found tucked in a Star Wars manual which also mentions how to tell if your HV transformer is (probably) bad, where to mount a fan to lengthen its life, and a possible way to tell if your tube is bad. I have no idea where it came from:
====================START====================
Atari STAR WARS HIGH-VOLTAGE BOARD
by Avery Petty
A.P. Engineering
Huntington Beach, CA
Recently, I repaired a whole fleet of Atari STAR WARS. I sent someone to the distributor to get the 'hard-to-find' high voltage transistor BU406D [NOTE: The transistor he is talking about Q3 labeled as "NPN 7-Amp. 400V Power Transistor" in the manual's parts list.]. He came back with a BU406, no "D". The "D" must appear on the transistor. It means there is a high voltage diode in the package. So beware, even the distributor can goof!
What will it cost you? Your game maybe. Without the diode, using the BU406, the high voltage will work for awhile [sic], but will burn up the flyback transformer which cost [sic] $90.00 [NOTE: It's much more than that now]!
If you are repairing a High Voltage board, and after replacing all the capacitors, the two 24 volt regulators, and related parts and the high voltage transistor with a BU406D, and you still don't have high voltage, and don't know why, you can be sure it's your flyback transformer. If in doubt, pull it out and put it in a working STAR WARS and see, it will only take 5 minutes [NOTE: this is a severe under-estimate; I'd say it is at least a 15 minute job not including swapping them back if that needs to be done, but then again he is a professional and I am just a hack :>].
When you finally fix it, put a fan under the board -mounted [sic] on the wood rail the board is mounted on, blowing on the High Voltage board. This is something that should be done to all STAR WARS, because the flyback is the most expensive part there [NOTE: advice to be heeded for all Atari color vector games].
If your high voltage won't get up to at least 19,000 volts, you may have a bad tube. Look for real [sic] bad phosphor burn or a color missing.
====================STOP=====================
Here is some text from the Major Havoc conversion kit installation instructions (TM-268). It describes the Atari sanctioned upgrade and includes instructions for converting the Amplifone Deflection Board PCB to the "official" upgrade. Thanks to Tony Jones (ant@palm.cray.com) for sending this to me.
====================START====================
[NOTE: Atari did copyright these documents and they are clearly marked with a copyright symbol.] Major Havoc Installation Instructions TM-268
I. MODIFY THE AMPLIFONE DEFLECTION PCB
NOTE: The following procedure applies to those Space Duel,
Gravitar, and Black Widow games that used an Amplifone display. If your
game has a Wells-Gardner display, perform "H. Modify the Wells-Gardner
Deflection PCB" [found later in this document].
Perform the following procedure to modify the Amplifone Deflection PCB
(see Figure 8).
====================STOP=====================
Here is an Atari Field Service bulletin courtesy of Al Kossow (aek@haxrus.apple.com) which describes modifications to the Amplifone monitor to make it more robust. All the diagnostic/repair stuff is new and compatible but the rest seems to be similar to part of the previous Major Havoc documentation upgrade but they do differ in some respects. I would advise that you only implement 1 of them unless you are sure they are compatible (I am not). If anybody knows if any are compatible (or not), let me know. For now, I am listing them as mutually-exclusive; mix at your own risk. I'd take the time and hassle to do the first one even though it is a lot more work.
====================START====================
[NOTE: To my knowledge, Atari never bothered to copyright these field service bulletins and they are not marked with a copyright symbol.] TECH TIP from the Atari FIELD SERVICE DEPARTMENT
Atari Color X-Y Display Deflection PCB
You should do the following modifications to help prevent the Deflection PCB from failing. THIS MODIFICATION SHOULD ONLY BE PERFORMED BY A QUALIFIED TECHNICIAN.
Parts List
Quantity Description Part No. ---------------------------------------------------- 6 Type-1N4002 Diode 31-1N4002 2 Type-1N754A 6.8V Zener Diode 131002-001 2 Type-1N756A 8.2V Zener Diode 32-1N756A 2 12 Ohm 5% 1/4 W resistor 110000-120
CATHODE +-+------+ +------+-+ CATHODE
--------+ |1N75#A+--------+1N75#A| +-------- Diode Connection
+-+------+ ANODES +------+-+
[NOTE: You get the idea; snub diodes across the deflection amps, back to back Zeners on the input to ground. Since I made these modifications, I haven't had a deflection amp go out (but I'm running the game with the back off now, too.)]
...
SOLUTION: Change the 10K Ohm resistor R83 on the Vector-Generator PCB to a 20K Ohm resistor.
STAR WARS Color X-Y Display [Amplifone ONLY; not Wells-Gardner models!]
PROBLEM: The BROWN zero-ohm jumpers (W1 or W2) on the Deflection PCB open up on the High-Voltage PCB. Zero-ohm resistors look like regular resistors, but are marked on the PCB assembly and the schematic with a W followed by a number.
SOLUTION: Replace the jumpers with pieces of wire. NOTE that the /white/ and /tan/ jumpers are good and don't have to be replaced.
STAR WARS Color X-Y Display [Amplifone ONLY; not Wells-Gardner models!]
PROBLEM: Capacitors C3 and C4 on the High-Voltage PCB may be defective. These are rated at 100uF, 35V.
SOLUTION: Change C3 and C4 to 220uF, 35V with a low E.S.R. (Effective Series Resistance) rating. The Atari part no. is 123009-227. The following manufacturers' capacitors will also work:
Illinois Capacitor, part no. 227 RMR 050M (50V)
Nichicon, part no. UPA1V221M (35V)
[NOTE: Digi-Key also sells "HFS SERIES Low Impedance" capacitors which will work. Dial 800.DIGIKEY and order part number P1339; my last catalog (April 1994) lists them for $1.68 each. The Nichicon capacitors should be obtainable from TTI. TTI is the nations largest distributor of passive components such as resistors and capacitors. Dial 800.CALL.TTI to place an order.]
\\\ A Warner Communications Company
FOR FURTHER INFORMATION CALL: (800) 538-1611
(800) 943-1120
====================STOP=====================
The following information is excerpted from a photocopy of a photocopy (of a...) which has no visible attribution or copyright. It appears to be from the Star*Tech Journal but I don't know for sure and the guy who sent it to me doesn't know where it came from.
====================START====================
PROBLEM: No filament voltage from the high voltage (HV) PCB.
SOLUTION: Check for a loose connection on the lugs that hold the HV transformer to the PCB.
PROBLEM: Can any other power transistors be used on the Deflection board?
SOLUTION: Yes, MJ 15003 NPN replaces 2N3716, and MJ15004 PNP replaces 2N3792 [NOTE: these substitutions are valid for the Wells-Gardner model, too].
PROBLEM: What should the output of the 555 IC on the HV PCB be?
SOLUTION: The output at pin 3 of the IC should be a 20-kHz square wave. This is adjusted with potentiometer R7.
PROBLEM: There is no high voltage. The positive and negative 24 volts are present.
SOLUTION: Check transistor Q3. The problem may be that the transistor tab (collector) may not be making good contact with the heat sink.
PROBLEM: The schematics for the HV cutoff circuit do not match the board assembly.
SOLUTION: There are three board revisions. You can tell which one you have from the table here. The schematics for all three boards are shown.
DISPLAY REVISION INDICATORS:
PCB Revision R16 R18 --------------------------------------------- Original 470 Ohms 27K Ohms First rev. Zener Missing or 27K Ohms Second rev. 470 Ohms 33K Ohms
o 24V
| |
| R15 CR2 |
+-----/\/\-----|<---+
| |
\ / Q4 c \ Q5 HV PIN 4
--- MCR100-3 =|------+-------+--------+----->
| e / 2N3904 | | |
+ | \ | C10 \
|\ | / R18 === 0.1uF / R19
| \ R16 \ \ 27K | 50V \ 68K
| +-------/\/\---->/ R17 / | /
| | 470 \ 1K | | |
| | / === === ===
| === C9 | = = =
| | .01uF |
+--+ |
| | DAG GROUND
=== +------------------------------->
=
o 24V
| |
| R15 CR2 |
+-----/\/\-----|<---+
| |
\ / Q4 c \ Q5 HV PIN 4
--- MCR100-3 =|------+-------+--------+----->
| e / 2N3904 | | |
+ | o | C10 \
|\ | === 0.1uF / R19
| \ 1N754 / \ R18 | 50V \ 68K
| +-------+->|---->/ R17 | /
| | | / \ 1K o | |
| | \ / | === ===
| === C9 / | | = =
| | .01uF \ 1K | |
+--+ / | |
| | | | DAG GROUND
=== === +--------+---------------------->
= =
o 24V
| |
| R15 CR2 |
+-----/\/\-----|<---+
| |
\ / Q4 c \ Q5 HV PIN 4
--- MCR100-3 =|------+-------+-------------->
| e / 2N3904 | |
+ | \ | C10
|\ | / R18 === 0.1uF
| \ R16 \---\ \ 33K | 50V
| +----/\/\---+ / \ / |
| | 470 | | 1N754 | |
| | | | \ ===
| === C9 | | / R17 =
| | .01uF +----+ +->\ 20K
+--+ | | /
| \ | | DAG GROUND
=== / R19 +--+---------------------->
= \ 1K
/
|
===
=
PROBLEM: The schematic for the deflection board shows CR5 as a 1N714 diode.
SOLUTION: The schematic number is wrong. It should be labeled a 1N751A zener diode. The rating of 5.1 volts is correct, however.
PROBLEM: On the HV PCB, the output voltage of the regulator is good when the pin is lifted, but there is no voltage when the pin is connected back to the board.
SOLUTION: Check for bad 0.1uF glass capacitor across the voltage regulator. The decoupling capacitor may be shorted.
PROBLEM: The 24-volt regulator has failed.
SOLUTION: Check for cracking around the regulator leads on the PCB. Also check for cracking around the leads of C3 and C4.
PROBLEM: The voltage is low on the supply lines on either the Deflection PCB or the HV PCB.
SOLUTION: There are jumpers on the supply lines of both boards. The jumpers are marked with a "W" on the schematic. They look like resistors on the board and have a single black band on them. The jumpers should have no resistance. However, the brown jumpers may have created some resistance to them. They should be replaced with a piece of wire. The white and tan jumper should have no problems.
PROBLEM: The picture shrinks in from the negative X and Y sides of the screen.
SOLUTION: On some deflection boards, R35 and R12 may have a 15 Ohm resistor and a 30 Ohm resistor in parallel to get 10 Ohms. If these come loose, then some picture shrinkage may occur.
====================STOP=====================
Unfortunately that's all I have for the Amplifone. It is worth noting that I recently acquired a copy of the Empire Strikes Back manual which includes the previous tech tip (2 sections above) in a condensed form that is mostly the same (it advocates replacing C3 and C4 as a matter of course, rather than waiting for them to cause a problem). Now I'll talk about specifics and what devices I often find bad in the Wells-Gardner color vector monitor. If you don't have a manual for this monitor, get a copy, as it does a good job of explaining how each section works and also how to adjust it.
For you people who don't like reading manuals, or who don't feel like locating local sources for specific parts or who don't want to hunt through a huge catalog to put together part numbers for an order, you can order everything you (probably) need (except for the upgrade parts and the extra capacitor for P329 versions of the HV unit) bundled together in one package from ZANEN ELECTRONICS. I suggest you order a couple of these to keep as spares since you never know when you might need to do a rush repair job and the price simply cannot be beat.
Call them at 806.793.6337 and ask for "get well kit #206" which at last count had 30 pieces including all the capacitors that go bad, 6 replacement chassis transistors, several of the smaller transistors (and their corresponding resistors), several diodes (including ZD902), and also (rather sparse) documentation on how to replace the parts. Please be careful if you decide to replace R918 (25K potentiometer) in the HV unit; it needs to start out adjusted to an in-circuit resistance of 5.5K when testing the upper 2 contacts of the 3. (this is the average of what I find to be the normal adjustment range which is always between 5K and 6K. If you have it maxed out you will probably damage your unit when you turn it on. I'm not sure why the kit includes this part as I've never come across a bad one yet.
Ordering a kit from them also entitles you to FREE technical assistance and they seem to be very experienced and knowledgeable. They take credit cards and do not charge anything for UPS shipping (< 7 days). You can tell them Gregg sent you if you want. As of December 1994, the price for this kit was $14.95 which is probably cheaper than any deal you could put together yourself, anyway. I should also mention that they sell a kit for the black and white vector monitors, too, specifically for the Electrohome G802/805 series which is "get well kit #104". They sell kits for most of the monitors that are/were commonly used in the industry; I cannot recommend Zanen and their kits highly enough.
This is a good way to go if you don't feel like doing any testing to find out what exactly is bad. If you replace all the parts included in this kit, you may be throwing out a lot of parts that still work OK (but which may be on their last legs, anyway), but you will be virtually assured of having a working monitor when you are done. If you get them all in and it still doesn't work, then go through the flowchart shown later in this document. It is quite likely that you have a bad HV transformer and you will have a heck of a time locating a replacement (I have a few but they won't last long) :<
Be aware that some of the parts that Zanen will send you are from the original spec and should not be used as this spec is known to be deficient. Consult the section below about how to upgrade the deflection boards and switch out the indicated parts for the upgraded replacements.
Here are some good parts places to get the big transistors (and other things) that I've used before:
Allied Electronics; 800.433.5700
Digi-Key; 800.344.4539
Mouser Electronics; 800.346.6873
Newark Electronics Chicago; 708.495.7740
Mouser also has the coin door "type 47" bulbs. Here are a few surplus type places that I've ordered from that have great prices on things like electrolytic capacitors that will be happy to send you a catalog:
All Electronics; 818.904.0524
Marlin P. Jones; 407.848.8236
Before we get started let me clear up something that causes a LOT of confusion when working on monitors of all types. All the documentation and boards for these monitors refer to "X" as the longer axis and "Y" as the shorter axis, independent of how the monitor is oriented in your game. Confusion arises because the game PCB will refer to "X" as the axis parallel to the floor and "Y" as the axis perpendicular to the floor and this is dependent on how your monitor is oriented. Why is this important to distinguish? Well if you notice that there is a horizontal line on your Tempest screen and you go to figure out why you aren't getting any "Y" deflection, you must check the "Y" portions of the vector generator circuitry on your game PCB but you need to check the "X" portions of your monitor (deflection board)!
Some words of caution about the manuals. I've got 3 versions of TM-183 (originals of the 1st and 2nd printings both from 1981 and a photocopy of the 3rd printing from 1982; let me know if you have an original of the 3rd printing that you'd be willing to sell). Also, if you are lucky enough to have a copy of the Wells-Gardner service manual for this monitor, the parts list on page 31 has an error; it lists C916 as .35uF when it is really .035uF. It is labeled properly in the schematic on page 28. None of the manuals show all the different versions of this monitor.
Since the 3rd printing is uncommon, I will describe the significant differences from the 2nd printing (not noting the layout changes such as replacing the crummy photographs with clear, sketched, exploded-view diagrams and minor rephrasings that are sprinkled throughout). All figures show later versions of all boards with the exception of Figure 13 which still shows the old deflection board (even though the parts list and everything else refer to the newer versions; obviously a mistake). Section 3 (Adjustable Controls) describes a later version of the neck board (P328). Section 5 (Purity, Convergence, and Tracking Adjustments) is completely rewritten and is MUCH less vague and more complete (2 pages longer). Section 6 (Details of Operation) has a section which discusses the Input Protection Circuit and has a schematic (Figure 8), too. There is also a new section G (Over-Voltage Protection) which describes the new circuit in the later version of the HV unit (P324).
The 3rd printing fixes some typos in the deflection PCB parts list:
Unfortunately, it also introduces one:
"D104, 105" changed from "Type-1N914B" to "Type-1N4001".
DO NOT MAKE THE ABOVE SUBSTITUTION AS IT WILL NOT WORK!!!!!
(*) R606 is incorrectly listed in all manual versions as being 1/4W when in reality it is always 1/2W.
Some changes were also due to parts upgrades and/or additional circuitry:
There are several manufactured variations (and many more upgrade variations) of each of the 3 boards (at least 3 for the deflection board and 2 for the other 2) The original designs are labeled P31X and the newer, more fault tolerant designs are labeled P32X. I also recently discovered a small cache of replacement deflection boards labeled P339 so there may be a whole 33X series, too! To add to the confusion, the Wells-Gardner service manual for "19K6400 series color vector monitors" shows a P341 version of the neck board, a P324 version of the HV unit, and a P322 version of the deflection board; I have never seen any of these versions.
Here is how to identify the versions of the boards that I have seen. The deflection boards are P314, P327 and P339. Some P314s were upgraded most of the way to P327s with a small piggy-back PCB on wire "stilts" at the top of the PCB (see "Input Protection Circuit", described later in this document). The neck boards are P315 and P328 (P328 has a brightness adjustment in one corner) and the HV power supply boards are P316 and P329 (P329 has an LED, HV limit pot, and an extra electrolytic capacitor, C22, which is supposed to be 10uF at 63V). After much very disturbing feedback about the performance of the monitors, Atari had all the boards redesigned to be more robust. The P32X (and P339) versions are the newer versions of the boards.
A close inspection of the P339 deflection boards reveals that they are, in reality, P327s with a P339 sticker covering the part number! I have verified that the PCBs are identical but have noticed several (possibly not all) differences between components on the 2 versions. Make the following changes on your P327, put a new label on it and you will have a virtual P339! All other components except for the diodes (didn't check them because they are too hard to read but it is extremely unlikely that any are different) are the same.
Differences between P327 and P339 deflection boards:
If you have a P314 board, in addition to the changes listed above, you should upgrade the following parts.
Differences between P314 and P327 (P339) deflection boards:
(*) The Zanen "Get Well Kit" uses the original specs and does not include these upgrades.
Since the circuits are essentially the same and since I have used 5 Amp fuses in P339/327 boards without any problems, it is safe to say that you can (and more importantly, probably should) put 6.25 amp fuses in your P314 boards at those 2 locations.
The very first run of P314 deflection boards had design defects in them which were evidently identified after the PCBs were produced but before they were populated (I make this assumption because I have never seen a board which did not have the corrections/substitutions on it). Anyways if your board says "85X0147" at the top then it is from the very first batch. Later batches say "85X0147C" (I have never seen an "A" or "B" flavor). The "C" flavor has C605 (.001uF +/-20%, Type-Z5F capacitor) in the upper right corner but since the plain flavor doesn't have a spot for it, it was soldered piggy-back onto R602. Some boards use a .005uF capacitor instead but you should change this to a .001uF if you have the soldering iron out anyway. The plain flavor has ZD100 labeled as R104 and ZD101 as R105, respectively, even though there are always Zener diodes in those spots regardless.
A comparison of the P315 and P329 versions of the HV PCBs and their documentation yields several conflicting differences which are summarized below. The values marked with an asterisk (*) are the ones I suggest you use regardless of which PCB you are working on (with the caveat that the resistors should be "matched"; don't just change the value of one without changing the values of all the others. The capacitor changes can be made individually). If you use all the asterisk marked values, you will upgrade your P315 to a P329 except that you, obviously, won't have the over-voltage protection portion of P329.
+-------+--------------------------------+--------------------------+ |Part # | Value in document or on PCB | Document/PCB referenced | +-------+--------------------------------+--------------------------+ |*C901 | 100uF @ 50V Alum Electrolytic | P329 HV unit PCB | | C901 | 100uF @ 35V Alum Electrolytic | P315 HV unit PCB | | C901 | 100uF @ 50V | TM-183 3rd printing Sch. | | C901 | 100uF @ 35V | TM-183 2nd printing Sch. | | C901 | 100uF @ 100V | 19K6400 service man Sch. | | C901 | 100uF @ 35V Alum Electrolytic | TM-183 3rd printing Fig. | | C901 | 100uF @ 35V Alum Electrolytic | TM-183 2nd printing Fig. | | C901 | 100uF @ 50V Alum Electrolytic | TM-183 3rd printing list | | C901 | 100uF @ 35V Alum Electrolytic | TM-183 2nd printing list | | C901 | 100uF @ 100V Alum Electrolytic | 19K6400 service man list | +-------+--------------------------------+--------------------------+ |*C902 | 100uF @ 50V Alum Electrolytic | P329 HV unit PCB | | C902 | 100uF @ 35V Alum Electrolytic | P315 HV unit PCB | | C902 | 100uF @ 50V | TM-183 3rd printing Sch. | | C902 | 100uF @ 35V | TM-183 2nd printing Sch. | | C902 | < part is not referenced > | 19K6400 service man Sch. | | C902 | 100uF @ 35V Alum Electrolytic | TM-183 3rd printing Fig. | | C902 | 100uF @ 35V Alum Electrolytic | TM-183 2nd printing Fig. | | C902 | 100uF @ 50V Alum Electrolytic | TM-183 3rd printing list | | C902 | 100uF @ 35V Alum Electrolytic | TM-183 2nd printing list | | C902 | < part is not referenced > | 19K6400 service man list | +-------+--------------------------------+--------------------------+ |*C905 | 33uF @ 160V Alum Electrolytic | P329 HV unit PCB | | C905 | 33uF @ 160V Alum Electrolytic | P315 HV unit PCB | | C905 | 33uF @ 150V | TM-183 3rd printing Sch. | | C905 | 33uF @ 150V | TM-183 2nd printing Sch. | | C905 | 33uF @ 63V | 19K6400 service man Sch. | | C905 | 33uF @ 150V Alum Electrolytic | TM-183 3rd printing Fig. | | C905 | 33uF @ 150V Alum Electrolytic | TM-183 2nd printing Fig. | | C905 | 33uF @ 63V Alum Electrolytic | TM-183 3rd printing list | | C905 | 33uF @ 150V Alum Electrolytic | TM-183 2nd printing list | | C905 | 33uF @ 63V Alum Electrolytic | 19K6400 service man list | +-------+--------------------------------+--------------------------+ |*C915 | .001uF +/- 20% Type Z5F | P329 HV unit PCB | | C915 | .001uF +/- 10% Ceramic | P315 HV unit PCB | | C915 | .001uF | TM-183 3rd printing Sch. | | C915 | .001uF | TM-183 2nd printing Sch. | | C915 | .001uF | 19K6400 service man Sch. | | C915 | < part's value is not shown > | TM-183 3rd printing Fig. | | C915 | .001uF | TM-183 2nd printing Fig. | | C915 | .001uF +/- 20% Type Z5F | TM-183 3rd printing list | | C915 | .001uF +/- 10% @ 500V Ceramic | TM-183 2nd printing list | | C915 | .001uF +/- 20% Type Z5F | 19K6400 service man list | +-------+--------------------------------+--------------------------+ | C919 | < part is not referenced > | P329 HV unit PCB | | C919 | < part is not referenced > | P315 HV unit PCB | | C919 | < part is not referenced > | TM-183 3rd printing Sch. | | C919 | < part is not referenced > | TM-183 2nd printing Sch. | | C919 | < part is not referenced > | 19K6400 service man Sch. | | C919 | < part is not referenced > | TM-183 3rd printing Fig. | | C919 | < part is not referenced > | TM-183 2nd printing Fig. | | C919 | < part is not referenced > | TM-183 3rd printing list | | C919 | 10uF @ 300V Alum Electrolytic | TM-183 2nd printing list | | C919 | < part is not referenced > | 19K6400 service man list | +-------+--------------------------------+--------------------------+ |*R901 | 3.9 +/- 5%, 3 W | P329 HV unit PCB | | R901 | 2.2 +/- 5%, 2 W | P315 HV unit PCB | | R901 | 3.9, 3 W | TM-183 3rd printing Sch. | | R901 | 2.2, 2 W | TM-183 2nd printing Sch. | | R901 | 3.9, | 19K6400 service man Sch. | | R901 | 2.2 +/- 5%, 2 W | TM-183 3rd printing Fig. | | R901 | 2.2 +/- 5%, 2 W | TM-183 2nd printing Fig. | | R901 | 3.9 +/- 5%, 3 W | TM-183 3rd printing list | | R901 | 2.2 +/- 5%, 2 W | TM-183 2nd printing list | | R901 | 3.9 +/-10%, 3 W | 19K6400 service man list | +-------+--------------------------------+--------------------------+ |*R907 | 3.9 +/- 5%, 3 W | P329 HV unit PCB | | R907 | 2.2 +/- 5%, 2 W | P315 HV unit PCB | | R907 | 3.9, 3 W | TM-183 3rd printing Sch. | | R907 | 2.2, 2 W | TM-183 2nd printing Sch. | | R907 | < part is not referenced > | 19K6400 service man Sch. | | R907 | 2.2 +/- 5%, 2 W | TM-183 3rd printing Fig. | | R907 | 2.2 +/- 5%, 2 W | TM-183 2nd printing Fig. | | R907 | 3.9 +/- 5%, 3 W | TM-183 3rd printing list | | R907 | 2.2 +/- 5%, 2 W | TM-183 2nd printing list | | R907 | < part is not referenced > | 19K6400 service man list | +-------+--------------------------------+--------------------------+ |*R910 | 6.8K +/- 5%, 1/4 W | P329 HV unit PCB | | R910 | 12K +/- 5%, 1/4 W | P315 HV unit PCB | | R910 | 6.8K | TM-183 3rd printing Sch. | | R910 | 12K | TM-183 2nd printing Sch. | | R910 | 12K | 19K6400 service man Sch. | | R910 | < part's value is not shown > | TM-183 3rd printing Fig. | | R910 | 12K +/- 5%, 1/4 W | TM-183 2nd printing Fig. | | R910 | 6.8K +/- 5%, 1/4 W | TM-183 3rd printing list | | R910 | 12K +/- 5%, 1/4 W | TM-183 2nd printing list | | R910 | 12K +/- 5%, 1/4 W | 19K6400 service man list | +-------+--------------------------------+--------------------------+ |*R911 | 4.7K +/- 5%, 1/4 W | P329 HV unit PCB | | R911 | 6.8K +/- 5%, 1/4 W | P315 HV unit PCB | | R911 | 4.7K | TM-183 3rd printing Sch. | | R911 | 6.8K | TM-183 2nd printing Sch. | | R911 | 6.8K | 19K6400 service man Sch. | | R911 | < part's value is not shown > | TM-183 3rd printing Fig. | | R911 | 6.8K | TM-183 2nd printing Fig. | | R911 | 4.7K +/- 5%, 1/4 W | TM-183 3rd printing list | | R911 | 6.8K +/- 5%, 1/4 W | TM-183 2nd printing list | | R911 | 6.8K +/- 5%, 1/4 W | 19K6400 service man list | +-------+--------------------------------+--------------------------+ |*R926 | 2.2 +/- 5%, 3 W | P329 HV unit PCB | | R926 | 2.2 +/- 5%, 2 W | P315 HV unit PCB | | R926 | 2.2, 2 W | TM-183 3rd printing Sch. | | R926 | 2.2, 2 W | TM-183 2nd printing Sch. | | R926 | 2.2, 2 W | 19K6400 service man Sch. | | R926 | < part's value is not shown > | TM-183 3rd printing Fig. | | R926 | 2.2, 2 W | TM-183 2nd printing Fig. | | R926 | 2.2 +/- 5%, 2 W | TM-183 3rd printing list | | R926 | 2.2 +/- 5%, 2 W | TM-183 2nd printing list | | R926 | 2.2 +/- 5%, 2 W | 19K6400 service man list | +-------+--------------------------------+--------------------------+
The good part of all this is that the 3 basic units, deflection board, neck board, and HV board are all interchangeable as units and they are all connectorized. In other words if you have one working monitor you can try the boards from your bad monitor (one at a time) even if the boards are not exactly the same. Also, the most often failing components are common to the different versions of the boards. If you have a vector monitor based game, it is really worth the effort and money to have a spare monitor handy (even if it is being used in another vector game) so that you can isolate exactly which board is bad when (not if) you have a failure.
Obviously, the neck board must be physically switched to be tested but you you don't have to unscrew the ground wires of the current PCB, or screw in the ground wires of the replacement PCB; you can just let the current PCB dangle and use alligator clips to connect the replacement neck board's ground wires to the chassis. With careful placement you can test a deflection board or HV unit without having to remove the one already in there. For the replacement HV unit simply connect the 3 connections and then use an alligator clip to ground the case to the chassis. Since you have grounded it, there is no need to attach it to the chassis; simply let it dangle by the secondary anode wire (the one with the suction cup) or the alligator clip but make sure it doesn't touch anything it shouldn't (keep the exposed underside of the PCB from touching anything). The replacement deflection board can sit on top of the current one separated by a piece of cardboard or other non-conductive material but getting it in there is more hassle than swapping so I usually pull the one that is in there and do a swap.
NOTE: There is 1 small exception to this universal compatibility rule for the neck board PCB. The P328 version uses a third (purple) wire running from the innermost (normally unused) pin of connector J501 to pin 8 of J900 on the HV unit. Without this wire, the new brightness control on P328 is disabled. Also, and this is VERY important, if you are using a P328 PCB on a P315 wiring harness (or vice-versa), you have to turn the J501 connector upside down. Don't worry too much about remembering the orientation because the connector's pins are gapped differently so it will only fit onto each PCB one way (the right way) without severely bending the pins on the neck board PCB (i.e. it is idiot-proof). This means that for testing purposes, you can swap boards and everything will be fine but if you want the functionality that the P328 potentiometer provides, you must remove the associated wiring harness that connects to J501 along with the board (or else add a new wire to the existing harness on the destination monitor). Without this wire, a P328 will behave exactly like a P315 and the pot will do nothing.
The very first thing you should do is check all the fuses in the machine with a meter. There are 4 on the deflection board and most Atari machines have 7 more in the power supply at the bottom of the machine (6 in a bay on the left and one under a black cap on the right). Remember to check resistance on the fuse HOLDER NOT ON THE FUSE. Many times a fuse will meter out OK but it isn't making good contact with the fuse holder so it is not conducting. If you always put your probes on the fuse holder, you will never get tricked by a bad contact. Many times fuses not conducting can be made to do so merely by reseating them after pinching the fuse holder clips tighter. Sometimes the clips are corroded and need to be cleaned first. The wire contacts connecting to the fuse holders may also not be conducting properly so you may want to move your leads and test there to cover all your bases. This rule applies to fuses in general anywhere you find them.
The only other components (besides the tube itself) are the six large TO-3 package transistors mounted to the chassis ("package" refers to the physical description of the transistor, NOT the electrical characteristics). The 3 NPNs are 2N3716s and the 3 PNPs are 2N3792s which are all in the final stages of the deflection amps or the power supplies. The deflection amps are like an audio push-pull amplifier and to power these amps the monitor takes AC in and produces plus and minus DC voltages.
Most of the failures in this monitor (as is the case with most electronic devices) are semiconductor failures, specifically, the transistors. All transistors discussed in this document can be tested in the same way; it doesn't matter if they are the large chassis-mounted transistors or the tiny PCB-mounted transistors. With the transistors out of circuit, set your multi-meter on Rx1K scale and use the following procedures.
NOTE: ANALOG AND DIGITAL MULTI-METERS REQUIRE DIFFERENT TESTING PROCEDURES FOR TRANSISTORS! For some reason, digital meters always show infinite resistance for all 6 combinations (if you accidentally get your skin involved it will show something around 2M Ohms). The best way to test transistors with a DMM is to make use of the "diode test" function which will be described after the analog test. For both methods, if you read a short circuit (0 Ohms or voltage drop of 0) or the transistor fails any of the readings, it is bad and must be replaced.
Anyway, there are 2 types of the large chassis transistors:
SPECIAL NOTE: Q705 and Q102 lie in such close proximity that it is not uncommon for their respective transistor sockets to be switched at some point which obviously swaps the corresponding functionalities (symptoms).
This gives reference frames for when the monitor is mounted horizontally (for games like Space Duel and Major Havoc) and vertically (for games like Tempest and Quantum).
For those of you without a manual, here is how to identify which one is which. The following descriptions are relative to the monitor oriented horizontally on it's base (like a TV would sit and like it is inside most games) and viewing it from the back side (so that you see the components and not the picture). 2 of them are on the outside of the chassis on the right side. The one nearest the back (component) side is Q606; the one nearest the front (viewing) side is Q605. On the inside of the bottom of the chassis are the other 4. The one on the far left nearest the HV unit is Q706. The one on the far right nearest the first 2 is Q103. The other of the 2 remaining middle ones which is closest to the back is Q102 and the last one which is in the same area but is closer to the front of the monitor is Q705.
An easy way to remember which kind of transistor goes where is to know that each connector has one of each kind; the 2N3716s are on pins 1, 3, and 4 (key at pin 2) and the 2N3792s are on pins 5, 6, and 7. If the wiring has not been altered, all 2N3716s are connected to the yellow, green, and red wires and all 2N3792s are connected to the purple, blue, and white wires. Here are 2 diagrams of the layout as viewed from the top:
+---------------------------------------+---------------------+ | (front; Picture Tube) | / | 2 _ | 2 _ / | N / \ 9 N / \ / | 3 / Q \ 0 3 / Q \ / | 7| 705 | | 7| 605 | / | 1 \ / d 1 \ / / | 6 \_/ e 6 \_/ / | 2 _ 2 _ g 2 _ / | N / \ N / \ r N / \ / | 3 / Q \ 3 / Q \ e 3 / Q \ / | 7| 706 | 7| 103 | e 7| 606 | / | 9 \ / 9 \ / | 9 \ / / | 2 \_/ 2 \_/ b 2 \_/ / | 2 _ e / | N / \ n / | 3 / Q \ d / | 7| 102 | | / | 1 \ / u / | 6 \_/ / | | / | (back) |/ +---------------------------------------+
or, more simply (where 2=2N3792 and 6=2N3716):
_________________
/ FRONT \
| Picture Tube |
|-------------------|
+-----+ 6 +-----+6
|HV | 2 |Def.2||
|Cage | 6 |PCB |2
+-----+------+-----+-
These transistors often go bad and here is a quick lesson on how to check a transistor with a meter. Unplug the red plugs from the deflection board to isolate the transistor from the circuit. From the bottom of the transistor, the configuration is (Oh boy; time for a picture!):
_
/ \
base -> /o o\ <- emitter
<>
| |
\ /<- the case is the collector
\_/
Pretty crude but you get the idea I hope. Test the transistors as described earlier, one by one, by placing the multi-meter leads on the tops of the pins of the red connectors or on the transistors themselves. Neither method requires the removal of the transistor from its socket so don't bother. You do, however, need to disconnect the associated connector from the deflection board prior to testing.
So what symptoms go with what? Well if only one of the deflection amplifying transistors goes then you will lose the corresponding half of the screen (for example if Q705 went bad in a Tempest game, you would be missing the top half of your screen). It won't actually be gone; it will be collapsed into a line across a 0 axis of the screen. If more than one goes or either of the power transistors (Q103 or Q102) goes you will get no picture because the spot killer turns on (and the LED on the deflection board lights) and shuts down the electron beam.
Checking these transistors is one of the first things you should do if parts of your screen are missing or your spot killer is on. Exact replacements are nice but I've successfully substituted others especially if you put the nonstandard transistors in the place of Q102 & Q103 as those two are for the + & - power supplies and not as critical (image-wise) as the ones that drive the deflection coils.
When replacing these transistors, make sure the socket is centered. Don't forget the little rubber or clear mica (plastic) insulator that was stuck to the chassis or to the bad transistor you just removed. You need to grease this insulator on both sides with a special grease called Silicone Heat Sink Compound. It is not strictly necessary but helps transfer the heat from the transistor to the chassis so the transistors last longer. The grease is pretty expensive so you may want to just buy new insulators (they should be about 10 cents each) because most come "pre-greased".
Don't be nervous about remembering the orientation; the pins are off centered in order to make the connection somewhat idiot-proof (see earlier ASCII picture. They are obviously "handed" but can be put in upside-down; it is a tight fit and hard to do but possible). Also, after you replace these and before you power the game up, use your meter to make sure none of the cases of the transistors are shorted to the chassis. This is very common and will cause fuses to blow and will probably destroy the transistor. If any part of the transistor is touching the chassis you are asking for trouble.
On the deflection board, the most common failures are Q100 and Q101 and when these go they take R100 and R101 (respectively) with them. These transistors are part of the + & - power supply circuit and are often bad with the resistors really burnt. To properly test these, they should be desoldered and removed from the PCB. Even in-circuit and not isolated from other components you can still get a pretty good idea with a multi-meter (analog meters work best since digital meters show infinite resistance most of the time) if the transistors are bad as transistors tend to fail catastrophically. In other words, they usually completely short (0 Ohms) or open. If you see 0 Ohms where there should be an open circuit or 2.5K Ohms, then the transistor is probably shorted. If you see greater than 2.5K Ohms when the reading should be in that range the transistor is probably open. When these transistors are bad, they usually show a large crack in the case if you look closely at them.
Replace Q100 with the same type transistor but if Q101 is bad (and even if it is not), I STRONGLY suggest you upgrade it to a larger transistors that will handle more current. I ALWAYS replace Q101 with a TO-202 package instead of the much smaller TO-92 package that the board comes with. In fact, the P327, and P339 versions were manufactured with this upgrade. The 3 labels I have seen are 119;NSDU57 (National Semiconductor) and M152;126-1A ("brandless"?), and NTE50 (NTE) [semi-colons denote a new line of text found underneath the previous line]. I always use NTE50s as they are relatively cheap and very easy to find.
Even though these transistors (and resistors) are the most common failures on the deflection board, I have NEVER seen them go bad after Q101 was upgraded to a NTE50. If you can't find the generic parts, a common modern day replacement for MPSA06 (Q100) is NTE287 and a common modern day replacement for MPSA56 (Q101) is NTE159 (but I cannot stress enough the utility of going with the larger replacement for Q101). Upgrading Q101 is always the first thing I do to any deflection board I get; replacing it before it fails saves me from having to replace the other parts that go bad when it does fail.
Once in a while you will see D105 or D104 open or shorted, too. Also watch for broken solder joints at the base of the connector pins for all the major connectors (especially on the deflection boards of black and white Wells-Gardner units which almost always are bad). You tend to rock the plugs back and forth when you pull the connectors and this often cracks the solder joints to the circuit boards which were poorly soldered to begin with. You may also want to check each pin for continuity with the next component on its trace line (and also with adjacent pins), and remove and resolder any dubious connections. While you are at it, resolder the 3 pins of the PTC thermistor (in the middle along the left edge of the deflection board) as they are almost always loose for some reason.
It is unusual but sometimes some of the 4 heat sinked (or is that "heat sunk"?) transistors on the deflection board will die. If any of these is bad, you will usually get no picture at all but you will see "background brightness" that lets you know some electrons are being thrown at the tube. Be sure to check the resistors and diodes around any bad transistors you find.
Usually, the electrolytic capacitors are still OK (though always be suspicious of electrolytics drying up and loosing micro-Farads). If the transistors in the chassis are OK, most missing pictures are due to problems with this board (whereas most distorted pictures are due to bad capacitors in the HV unit). I frequently see HV units with the protective shield removed from the case and discarded in attempt to keep it cooler. I like to keep mine on because I rate dust and foreign object attraction as a more severe problem than heat for this board but like I have said, I don't let my stuff run hot.
Very infrequently, you may have problems with some other transistors in the X/Y amp section of the board. Most of the rest of the transistors that populate the deflection board (Q600-602,700-702) are type TPS98 and are not easily found anymore. The good news is that TPS98 is equivalent to the PN3569 and the ECG or NTE 194. All Electronics (800-826-5432) has PN3569 transistors at 5 for $0.50. NOTE also that All has just dropped their minimum order requirement (still $5 S&H on most orders, though).
The neck board very seldom has problems. The few I've seen are from mishandling where someone has broken some of the pots that control the RGB drives. Check the pots if you are missing a color. If you are blowing your 5A fuses and your other boards are OK, check C503 (33 uF @ 250V). If this is open, shorted or cold soldered, it will cause the 5 (or 6.25 depending on your board) fuses to blow.
Last is the HV supply. I've worked on lots of these and have only seen one of the infamous bad HV transformers. Normally HV failures are due to a semiconductor or capacitor failure. I must mention that the HV unit can put out very weak X-ray radiation and and creates lots of ions in the air but both are in sufficiently small quantities that there is little risk of injury. Nonetheless, many people feel a tad queasy during or after working near high voltage. Like anything else, it gets less noticeable with successive exposures. Many people are quite worried the first time they experience the sensation but it is harmless. Please note that I am not a doctor nor a radiation specialist so refer back to the CYA clause at the beginning of this document. Certain unlikely faults that I have never run across could cause large amounts of X-rays to be produced which would definitely be harmful.
Before you work on this beast, discharge the tube as it can really zap you even when turned off (it is extremely inadvisable to work on the HV section while the machine is on or even plugged in; always unplug the game before you go in here). Connect a clip lead between the chassis and the shaft of a long narrow plastic-handled screwdriver. Work the end of the screwdriver under the big suction cup on the top of the tube until you hit metal. There will often be a snap (from the spark) as the HV runs at around 20 thousand volts. Just go slowly and use only one hand. It won't bite as long as you are careful. You may want to leave the game plugged in BUT TURNED OFF for this step so that you can ground to the earth instead of just the chassis. If you plan to remove the HV unit, you must disconnect the secondary anode from the tube which is a little tricky. Under that suction cup is a double-barb. The barbs extend perpendicular to the wire as it enters the suction cup. Simply pinch the suction cup as best as you can and wiggle it back and forth while pushing in at the edges and pulling out at the center. It will eventually come off. Here is a cut-away depiction of the anode; the wire will run perpendicular to this view (i.e. towards/away from the reader):
| /\ /\ |
\ \ / /
\____|_|____/
When I was in the habit, I discharged the tube with my HV probe so I could watch the voltage go down as the internal resistance of the probe bled the voltage off slowly. If the snap bothers you, put a resistor in series with your clip lead to drain off the voltage more slowly. If you don't have this equipment available, a 1 or 2 hour wait after unplugging the game should be sufficient for most of the excess charge to bleed off naturally. NOTE: The anode is designed to hold onto charge so it will NEVER discharge completely without being deliberately grounded. In fact, if you wait a couple of days after grounding it, it will actually build up another (small) charge! I suggest that if you go through the trouble of discharging it, you should keep it grounded by using an alligator clip on the end of your wire and leaving it connected to your ground. This way you have no chance of getting shocked (just be ABSOLUTELY CERTAIN to remove this ground wire before you turn the power back on again).
Personally, I never worry about any of this anymore since the shock (when received properly) is harmless and mostly painless (I have gotten zapped dozens of times). Just make sure the game is unplugged first. If you aren't going to wait, follow the "1 hand rule"; only use one hand when disconnecting the cable and keep the other one in your pocket or in the air. The only likely way for the charge on an unplugged machine to hurt you is for it to form a circuit between your 2 hands (one grounded and one on the tube) sending current directly across your heart; these levels could easily interfere with your heartbeat and even cause it to stop! I should also point out that black and white monitors use significantly lower high voltage than do color monitors and raster monitors have high voltages that are and order of magnitude higher than vector monitors use. I have been shocked by them all and assure you that rasters DEFINITELY have a bigger sting than do vectors so beware!
This flowchart is excerpted from a photocopy of a photocopy (of a...) which has no visible attribution or copyright. It appears to be from the Star*Tech Journal but I don't know for sure and the guy who sent it to me doesn't know where it came from.
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Most problems in the Tempest display can be found by following the procedure shown in the chart below.
CAUTION: When replacing the transistors mounted on the chassis, make sure the pins do not short to the chassis. If the chart procedures do not solve your problem, call Atari Field Service [NOTE: They will be of little help nowadays :>].
[NOTE: I have taken considerable liberty in restructuring the flow and rewriting the text in order to be more clear than the original chart and to better fit in 80 column text format. I have added a couple of things, too.]
No picture and...
+--------YES---- 5 amp fuse (F100 or F101)----NO-------+
| on Deflection PCB blows? |
\|/ \|/
Cannot get/keep +/- 28 Volts. Turn up brightness and contrast controls
Disconnect P600, P700, and<--------+ on HV PCB. Is there a dot in the center
P100. Power up monitor. | of the screen?-----------------+
| | | +-------+ |
\|/ | NO | | | YES |
Fuse still blows?-------NO-------+ | \|/ \|/ | \|/
| | | Is there +/- 28V on | Is there 180V on
YES | | | on pins 1/8 of P900? | pin 5 of P900?
\|/ | | | | | | |
Replace the following components | | NO | YES | +-----+ YES | NO
if shorted: D100, D101, D102, | | | | |
D103, C100, and C101 | +--------+ +----------------------+
| | |
+-----------------------+ \|/
\|/ Change or make sure C901 and C902 are
Check for Q102/3 collector short to 100uF at 50 volts. Check for a leaky
chassis. Replace the following compo- C905. If C905 is bad, also check or
nents if defective: Q100, Q101, D104, replace Q900, Q901, Q902, Q903. Is
D105, ZD100, ZD101, Q102, and Q103. there 180 volts on pin 5 of P900 now?-+
| | |
\|/ NO | YES |
Connect P100 and power up. Is | |
the +/- 28V on pins 4/5 of P100 Check resistors R100, | |
OK now?--+--------------NO------------->R101, R102, and R103 | |
| for open circuits. | |
YES | | | |
\|/ +------------+ | |
Replace the following components | \|/ |
if defective: Q603, Q605, Q606,<---+ Double-check the above transistors. |
Q703, Q705, Q706. Also look for burnt (open or shorted) |
| resistors R903, R904, R905, R906, or |
\|/ R907. | |
Connect P600 and P700 and power | |
up. Picture now?-------YES--------+---------------------+--------------------+
| |
NO | | Is picture "blooming" (does the image
\|/ +--->appear as though being viewed through
Check remaining transistors | a magnifying glass)? |
in the X and Y amplifiers. | | |
Then make sure the following-------+ NO | YES |
resistors are not open: R702, \|/ \|/
R703, R711, R712, R602, R603, >END<----Replace ZD902 on HV PCB.
R611, and R612. / \
====================STOP=====================
Let's finish off with a troubleshooting guide broken down by symptoms. Much of the rest of this section is a transcription of repair notes from a Wells-Gardner technician. Just because your symptom matches something in here is no guarantee that what I/he found wrong is the same thing that is wrong with your board, but it's a good place to start. Most of the problems he listed in his notes were due to manufacturing defects or incompetent repair work. Obviously, if your monitor was working OK and then simply stopped, those things are not likely be your problem. If you have seen any problems that are not listed in this section, please contact me and I will add them.
Display "implodes" during intermission screen between player one and player two and sometimes on the "figure 8" levels (Tempest machines only): I thought I knew what was causing this but upon further evaluation, my solution didn't make sense (although it did work for me the only time I had this problem). Until I get another board to fix that has this problem, I only have general advice on how to avoid the problem. Adjust your game board and "shrink" the Y deflection some and this should help. There are 2 sets of ROMs for this game and the "compact" ROM set (only half the ROM sockets are used) is slightly different (the intermission screen has some other stuff such as the copyright and credits information at the bottom of the screen which "balances" it out) so the spot killer won't get confused and decide that the bottom half of the screen is wiped out. These PCBs do not normally experience this difficulty.
Check the fuses first. If they are OK, then check the 6 transistors mounted on the chassis as described earlier. If you find at least 2 of the deflection ones or 1 of the power ones bad, then that is definitely tripping the spot killer. A good trick to figure out where the problem exists is to turn your brightness up all the way and see what your picture looks like. The spot killer doesn't turn the Z signal all the way off so if you turn the brightness all the way up, you should be able to see a very faint picture. Based on what the picture looks like, you can decide which half of the circuit is causing the problem (either the X or Y portion). If you know it is a problem on your deflection board (i.e. swapping another board in makes the monitor work) then check R808 (X) and R809 (Y) to make sure they are not open. These resistors allows current to flow to the spot killer circuitry and if they open then the spot killer thinks something has happened to the amplifier circuitry so it kicks on. You can tell if this is your problem by turning the brightness on all the way; if you see a complete picture, then this may be your problem. If all this is OK then you probably have a game board problem, particularly if you are unable to "play" the game (see the credit lights blink after you punch up credits and hear the game sounds after you push start).
The problem is most likely Q603. Occasionally you will see Q603 (Q703), or Q604 (Q704) go bad. If one does, be sure to check the resistors and diodes around it, particularly R611 (R711), R612 (R712), and D602 (D702). A common modern day replacement for MPSU57 (Q603/Q703) is NTE189 and the part for MPSU07 (Q604/Q704) is NTE188. These should be greased where they touch the heat sink (like the chassis transistors) to improve heat dissipation. If you are having trouble with these failing, you might want to beef them up by using TO-202 package upgrades to NTE50 (MPSU57) and NTE49 (MPSU07).
Jeff Young from World Wide Distributors in Grand Rapids, MI reported some words of caution about these resistors on Page 3 of the November 1982 issue of the Star*Tech Journal:
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====================STOP=====================
The resistor is burning up because of runaway current from the HV unit. You can confirm this by replacing R101 and testing the deflection board in a known good monitor (or by putting a known good HV unit in the monitor that is acting up); if R101 doesn't burn up then you know the HV unit is the culprit. Whenever this has happened to me, R903 in the HV unit has been the cause. It will sometimes short and this causes so much current to flow to the deflection board that the puny 15 Ohm resistor burns up. If this goes on for too long, Q101 may fail or occasionally R901 will burn up to an open circuit.
I have seen this several times and the problem has always been a bad ZD101. Much of the time this causes R101/Q101 to fry and spot killer comes on.
The image is extremely shaky and unstable and lines that should be straight have periodic wiggles along their length that make them look like an EKG (the distortion is sort of like when you watch TV with a bad antennae and lines "walk" around on the screen).
Replace C901, C902, and/or C905 in the HV supply. If of these is bad then the rest of the electrolytic capacitors are probably in pretty poor condition too, so I generally replace all of them. Make sure the replacements are rated at as least as many "working volts DC" WVDC and have as least as many micro-Farads. It doesn't hurt to replace a 22uF @ 50V capacitor with a 50uf @ 100V if that is all you have around. More Voltage capacity is equal or better but it is best to keep the capacitance the same if you can. Also when ordering and replacing these, be aware that they are polarized and not idiot-proof; be sure to put them in the circuit so that they are oriented properly. The casing will clearly indicate either the negative or the positive terminal (but typically not both) and the industry convention is for the positive lead of the capacitor to be longer than the negative lead. Be aware that P329 has an extra capacitor (C22) that may not be shown in your manual; its value is 10uf at 63V.
The picture is overly bright and all parts check out OK.
Look for a broken circuit board trace between pin 6 of the high voltage transformer and the anode of diode D901. This trace is prone to breaking open. It is probably easier to just add a jumper and see if it solves the problem or else check the connection (with board removed) with a meter to make sure it is a short.
Check the transistors in the HV unit as described earlier. The ones I've seen fail most often are Q903, Q902, and Q901 though they are all suspect. These transistors will usually have cracks in the casing if they are bad so look closely at them. If all this stuff is OK, look at the electrolytic capacitors (they are the big cylindrical tube-like parts and are usually blue in color) in the circuit. They come in two "types":
_____
_____ | |
--| |-- axial-lead | |
~~~~~ +---+
radial-lead | |
One quick errata: The parts list in Figure 15 of TM-183 lists all capacitors as fixed axial-lead when in reality only C905 is; the others are all radial-lead. These are designed to burst open (VENT) when they fail due to overburdening (but they sometimes don't) so as to be obvious to repairpersons. The top (for radial-leads) or the side (for axial-leads) will be open and some of the "guts" will be hanging out. When some capacitors go bad, they sometimes take the final output resistors R901 and/or R907 with them (but the resistors will look perfectly OK unless you check them with a meter). Also check to make sure that connector J901 inside the HV unit is intact; on person reported that the plastic in his disintegrated on the inside and the wires came loose. If these are OK, check the following:
Here is a really strange one about a problem with the tube itself!
Focus starts out sharp but slowly gets fuzzy and then suddenly snaps back into clear focus (repeat every 10 seconds; eventually will stay out of focus all the time).
I didn't see the problem until I extended the wiring harness out of the back of the machine so the monitor was sitting on a stand, because there WAS arcing occurring, but it was inside the picture tube socket. There's a white, cubic lump attached to the end of the neck (where the neck board attaches) where all the pins are and I could see a faint glow out of it when the monitor freaked. The focus line from the HV power supply connects to the pin nearest the cube. Inside of it, a sort of spark gap is implemented by running the focus wire under and in contact with a small metal plate (the wire eventually connects to the socket pin). A second formed wire is suspended above the metal plate with the point of a V bend in the wire forming a spark gap with the metal plate; this formed wire is connected to chassis ground. Its purpose is to form a spark gap with certain pins in the socket; the intent is to prevent damage to the gun of the CRT during power down. In my case, the focus wire had lost good contact with the socket pin, and some internal arcing of some sort appeared to have released the metal plate from where the plastic housing was supposed to retain it, causing the spark gap to become too small. So it appears one problem led to another. The connection to the focus pin of the picture tube socket had become intermittent. Some arcing caused the built-in spark gap to come apart. A similar problem with the same symptoms can develop causing a dead short to ground of the focus electrode. Within the socket, there is a plate in the back of the socket which is grounded. If any moisture or conductive crud gets in there, you can get a low resistance path between the grounded plate and the focus pin. To fix it, you have to desolder the socket and break it open. The socket simply pries apart but it was originally staked, so don't be alarmed if you see small pieces of plastic flying off when you pry the sucker open. I found it went together tightly enough that I wasn't concerned about it falling apart but you could use a touch of glue just to be sure. I soldered the metal piece to the focus wire, placed it back in its retaining channel, cleaned out the gap area and soldered the socket back in place. The part that comes off the bottom of the socket to gain access to the internals touches the PC board when the socket is installed, and is retained just fine when the socket is in place without gluing.
All the above is assuming you just plug the game in and it doesn't work. If you happen to be playing the game at the time it fails, you have a little more information to go on. If you hear a loud bang like a firecracker, then check the capacitors on the HV board first because they can be loud when they burst. If you see a little bit of smoke inside the cabinet and smell a hint of "electrical smell", then check the fuses first. If you see a ton of smoke inside the cabinet, then check the large transistors on the chassis first. If you start losing quadrants of your screen intermittently than I would advise replacing the corresponding transistor before it fails because it can take other components (usually fuses) with it when it goes altogether. The same advice goes for the blooming caused by ZD902.
Now some things besides the monitor itself. Tempest is harder on this monitor than the other Atari vector games. The attract mode that displays "TEMPEST" (often burned right into the phosphors) really stresses the monitor. For Tempest, I like to do what Atari did when they offered the Major Havoc conversion. Add a fan to the back door of the game. I try to find a small cooling fan that just moves a small amount of air (not one that howls). You have to cut a hole in the back door and position it so it directs air at the deflection board. I usually connect the power for the fan to the wires that head up to the fluorescent light and put a connector in so that you can still remove the back door (with the fan mounted on it) without it hanging on the wires to the fan.
If you would like to greatly reduce your chances of experiencing a monitor failure in your Tempest machine, you may want to "shrink" the screen in both axes using the X and Y "SIZE" pots on the game board. I also have heard Tempest was bad, because it draws a diagonal retrace line (Z/brightness off) from the bottom left corner to top right corner during the attract mode. There was supposed to be a ROM fix, which took this line out and really helped the transistors but I've never seen it. I could probably buy it, as it was supposed to have been pushed for by a local operator.
All of this has assumed that you had a good logic board in the game and the monitor was receiving the vector info. If the spot killer stays on and the monitor seems OK verify the presence of the X and Y signals by measuring between ground and pin 7 of the big white connector for the X signal and pin 8 for the Y signal. This is an AC signal and if either is missing the spot killer circuit is just doing it's job and saving the tube's phosphors.
You might also want to check that you don't have static analog data (voltage) saturating your transistors. To check this, set your multi-meter on the DC voltage scale and measure the voltage on the lead of R600 and R700 which are connected to the yellow and orange wires, respectively. The correct voltage should average out to about 0 volts DC but will fluctuate (both positive and negative) because of the changing deflection signal. If the measured voltage is constant (between 5 and 15 volts positive or negative DC) then check the X and Y amplifiers on the game board.
Now that you have a working monitor (and game), it is time to fine tune your picture. Before making any adjustments, turn your game on and let it warm up for at least 10 minutes. R918 is the HV adjust and my advice is that unless you have a HV probe, don't mess with it. If you have a probe, set the HV for 19.5 kV with zero beam current (i.e. with the game boards disconnected from the machine so that no input signals are being supplied).
Some HV supplies (P329) have a circuit called the HV over-voltage protection circuit. It monitors the voltage of the focus assembly in the secondary circuit of T900. If the high-voltage at the anode of the picture tube increases beyond the threshold set by H.V. TRIP adjustment R930, this circuit shuts off the timer of IC901 and LED D903 turns on to indicate the over-voltage condition. Presumably, this was added to help discourage Tempest from eating HV transformers as it is prone to do since they are by far the most expensive component in the game. If you know your HV is good, adjust R930 so that it is just beyond the point where LED D903 lights (so that the LED is off).
NOTE: The following adjustments are a 2 person job (unless you are very handy with mirrors) because it is nearly impossible to view the screen and turn the pots at the same time. When adjusting your monitor, all adjustments should be made in the order as presented below as many of the adjustments have effects on other qualities and will cause you to have to go back and redo them if you change the order.
On the outside of the HV assembly are focus and brightness adjustments. Adjust the focus until the picture is sharp then adjust the brightness just under the point where the dot in the center starts to show or just under the point where you can see the connecting lines between objects. Be careful to not get carried away with the brightness as you can do permanent damage to the phosphors.
The manuals don't talk much about adjusting the positioning and size of your screen but that is easy to do. There are small potentiometers on the game board that are clearly labeled which control X and Y centering as well as X and Y size.
The following adjustments refer to the 8 tiny blue and/or black potentiometers found on the large game board towards the back on a Tempest machine. If your lines are not meeting at the "joints" properly or your text and numbers aren't lined up properly on the statistics screen then you need to make these adjustments. This information is directly from the Tempest schematic diagram supplements (sheet 2, side B, 3rd printing) so locations/numbering/labeling of the pots may be different for other vector games but the instructions should be relatively portable...
====================START====================
[NOTE: Atari did copyright these documents and they are clearly marked with a copyright symbol.]
[NOTE: All of the following controls exist in the Vector Generator section of the game PCB; THEY ARE NOT IN THE MONITOR!]
+------+ +------+ +------+ |/\/\/\| | | | | | | |\/\/\/| | | | | | | |/\/\/\| | | | | | | |\/\/\/| |--- | |--+---| |/\/\/\| | -----| | | | |01..YZ| | | | | | | |\/\/\/| | | | | | | +------+ +------+ +------+ screen I screen J screen K
====================STOP=====================
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This information comes from the Wells-Gardner Service Manual.
====================START====================
As far as adjusting purity (red gun hits red phosphors only, green gun hits green, etc.) and convergence (red, green, and blue guns hit adjacent dots to make white instead of separate colors), that is a whole different subject and the manual does a decent job of walking you through the procedure.
For best results, it is recommended that purity adjustment be made with display unit facing west or east. The display unit must have been operating 15 minutes or more prior to this procedure.
With yoke on CRT neck, set convergence assembly on CRT neck with the center line (of Purity Adjustment Magnet) over gap between grids No. 3 and No. 4. The convergence assembly consists of 3 sets of ring magnets with tabs (Figure 6).
FIGURE 6:
------------------- +-----------+
\ / /-+ |===========| <- Purity Adj.
////////////////======| | |===========| <- Red/Blue Adj. (4 pole)
-------------- \-+ |===========| <- Red/Blue
| +--+ | +-+----II-----+ on Green Adj. (6 pole)
|+-| |-+| +-+-----------+
|| | | || <- Grid No. 4 TOP VIEW
|+-| |-+| /|\
| | | | <- last gap | Concentric Convergence
|+-| |-+| s Assembly shown in zero
|| | | || <- Grid No. 3 c correction position.
||_| |_|| r
|| | | || <- Grid No. 2 e REAR VIEW
|| | | || w __
|+-| |-+| | / \
| | | | <- first gap | |++| <- Tabs of ring magnets all
|+-| |-+| \|/ _||||_ in vertical position.
||-| |-|| <- Grid No. 1 / ____ \
||=| |=|| ===/ / \ \
| \+--+/ | ~| | | |
\ | | / ~| | | |
\| |/ -~-\ \____/ /
====== ~ \______/
|||||| II
Tabs of the 3 magnetic ring-pairs are to be in a vertical position which will produce a zero-correction state and facilitate adjustments. (Figure 6).
Connect a generator or game (self-test mode) which can generate a crosshatch patter of red, green and blue inependently and in combination of colors. Refer to "INTERFACE BOARD ADJUSTMENTS" for input signal level and pattern size.
With a green crosshatch pattern, pull the deflection yoke backward as far as it will go. The center vertical portion will be green. If green is not horizontally centered between other colors, move the 2 purity magnets with respect to each other in order to center green crosshatch on the screen.
Push deflection yoke forward gradually, until crosshatch is a uniform green (pur in color) across the entire pattern. The deflection yoke should be secured in place.
Both red and blue colors are to be checked for uniformity and true color. Reposition the deflection yoke, if necessary, to obtain optimum purity of all colors. Tighten clamp to secure deflection yoke.
4-Pole Magnets and 6-Pole Magnets are for static convergence.
[NOTE: This text refers to a monitor oriented in the proper horizontal position. Some games such as Tempest use the monitor rotated 90 degrees into the vertical poisition.]
NOTE:
_
| | <---------- Temporarily Installed Wedge
___|_|___
/\ /_________\ /\
/ \// \\/ \ <- Rubber Wedge
\ // \\ / (60 degrees from Temporary)
\// +---------+ \\/
// | ___ | \\
|| | / \ <--------- CRT Neck
|| | | | | ||
|| | \___/ | ||
\\ | | //
\\ +---------+<------- Deflection Yoke
\\ //
\\_________//
\_________/
| |
|_|
FIGURE 8A
+---------------------------+ | B G R | Insert rubber wedge | \ | / | from upper (right for | \ | / | Tempest) side | R___ \ | / ___B | | | ---___\|/___--- | S V v | G----------*----------G | I I / \ / | ___---/|\---___ | D E / \ / | B--- / | \ ---R | E W / DY \/ | / | \ | / /-----+ | / | \ | ------/------+ | R G B | / +---------------------------+ /FIGURE 8B
+---------------------------+ \ | R G B | \ | \ | / | ------\------+ | \ | / | \ \-----+ | B___ \ | / ___R | S V \ DY /\ | ---___\|/___--- | I I \ / \ | G----------*----------G | D E \ / \ | ___---/|\---___ | E W ^ | R--- / | \ ---B | | | / | \ | Insert rubber wedge | / | \ | from lower (left for | B G R | Tempest) side +---------------------------+FIGURE 9A
+---------------------------+ TOP VIEW |+-------------------------+| /\ ||+-----------------------+|| / \ / ||| ||| / DX \/ ||| ||| +-> / /| ||| |G| | -----/|| ||| B|R | / || ||| ||| | ++ ||| ||| | ||| ||| Insert rubber wedge ||+-----------------------+|| from left (top for |+-------------------------+| Tempest) side +---------------------------+FIGURE 9B
+---------------------------+ TOP VIEW |+-------------------------+| /\ ||+-----------------------+|| \ / \ ||| ||| \/ DX \ ||| ||| |\ \ <-+ ||| |G| ||\----- | ||| R|B || \ | ||| ||| ++ | ||| ||| | ||| ||| Insert rubber wedge ||+-----------------------+|| from right (bottom |+-------------------------+| for Tempest) side +---------------------------+
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Now that you have your monitor repaired and adjusted, I'll discuss the variety of ways that exist to make your monitor (or rather, your deflection board) more robust and hopefully reduce or eliminate future failures.
Here is some text from the Major Havoc conversion kit installation instructions (TM-268). It describes the Atari sanctioned upgrades and includes instructions for converting all Wells-Gardner P314 Deflection Board PCB variations to Atari's "official" upgrade. Thanks to Tony Jones (ant@palm.cray.com) for sending this to me.
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H. MODIFY THE WELLS-GARDNER DEFLECTION PCB
NOTE The following procedure applies to those Space Duel, Gravitar, and Black Widow games that used a Wells-Gardner display. If your game has an Amplifone display, proceed to I. Modify the Amplifone Deflection PCB [found earlier in this document].
Four versions of the Wells-Gardner display were used in the Space Duel, Gravitar, [Tempest,] and Black Widow games. Perform the preliminary procedure for all versions of the display, then refer to Table 3 to determine which version of the four displays was installed in your game and perform the additional procedure for that version. CAUTION! When soldering components to the display circuitry, apply just enough heat to provide a proper electrical connection. Excessive heat can damage the semiconductor material.
Perform the following procedure to modify the Deflection PCB (see Figures 6 and 7).
Solder Here
|
CATHODE +-+------+ \|/ +------+-+ CATHODE
--------+ |1N75#A+--------+1N75#A| +--------
+-+------+ ANODES +------+-+
----|<---- ---->|----
Figure 6 IN754A and 1N756A Zener-Diode Connections
[Figure 7, entitled "Modifying the Wells-Gardner Deflection PCB", showing 2 half scale pictures of the solder side of the Deflection PCB, has been omitted for obvious reasons. It does not show anything that cannot be derived from the included text; it was merely a "visual aid". The top picture is the P327/339 design and the bottom is P314.]
Table 3 Display Versions
Perform the following procedure for Version 1 of the Wells-Gardner display.
Perform the following procedure for Version 2 of the Wells-Gardner display.
Perform the following procedure for Version 3 of the Wells-Gardner display.
Perform the following procedure for Version 4 of the Wells-Gardner display. NOTE: This version of the display requires that an Input Protection Circuit PCB assembly be installed on the Deflection PCB as part of the display modification procedure. This PCB assembly is not included in the kit. However, to obtain the Input Protection Circuit PCB assembly, use the order form at the back of this document.
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The following are hardware modifications you can make to the deflection board to improve its reliability. I have seen all in action and can verify them to be "non-lethal" modifications but cannot really attest to their usefulness since I don't run my Tempest under stress. I would advise that you only implement 1 of them unless you are sure they are compatible (I am not). If anybody knows if any are compatible (or not), let me know. For now, I am listing them as mutually-exclusive; mix at your own risk. I'd take the time and hassle to do the first one even though it is a lot more work.
The Input Protection Circuit did not include any background in the kit so here are those details which I found on page 3 of the May 1982 issue of Star*Tech Journal:
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NEW INPUT PROTECTION CIRCUIT FOR WELLS-GARDNER COLOR X-Y DISPLAY
This display contains an additional small printed-circuit board (PCB). The PCB is mounted in "piggy-back" style on top of the Deflection PCB.
The input protection board was added to protect the fuses in the display from damaging input voltage conditions. Without this board, the display fuses might blow in the event of an intermittent or long-term game PCB failure. With this board, the screen will momentarily go blank if the average X- or Y-axis voltage(s) exceed a certain level. The screen then automatically recovers for normal game play and earning when the voltage(s) return to normal.
If this display is used in Atari "Tempest" games, be sure to correctly adjust the X and Y SIZE and CTR video pots on the "Tempest" Analog Vector-Generator (main) PCB. The instructions for the adjustments are printed on the "Tempest" schematics - Sheet 2, Side B - 3rd printing or later [and can also be found in this document]. Improper adjustment may cause the screen to go blank during normal game play.
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[NOTE: To my knowledge, Atari never bothered to copyright these instructions and they are not marked with a copyright symbol.]
[NOTE: THIS MODIFICATION IS FOR P314 VERSIONS OF THE DEFLECTION BOARD ONLY. The P327 and P339 versions already have this circuit designed into the board. Here is the text from Atari CO-183-02 (1st printing) which describes a circuit that was sold by Atari to help make the deflection board more robust. This circuit is unavailable but very simple and easy to recreate from the schematics provided herein.]
[NOTE: Martin Sterni <m-sterni@dsv.su.se> has successfully prototyped these and is currently selling them WITHOUT ANY COMPONENTS. He has sent me a few samples and they are of SUPERB quality (nicer than the original Atari/Wells-Gardner PCBs). I can vouch for them being produced properly in every way; I am very impressed! Contact him if you want to purchase any.]
This display contains an additional small printed-circuit board (PCB) that is not described in the display manual (TM-183). The PCB is mounted in "piggy-back" style on top of the Deflection PCB.
The input protection board was added to protect the fuses in the display from damaging input voltage conditions. Without this board, the display fuses might blow in the event of an intermittent or long-term game PCB failure. With this board, the screen will momentarily go blank if the average X- or Y-axis voltage(s) exceed a certain level. The screen then automatically recovers for normal game play and earning when the voltage(s) return to normal.
If this display is used in a Tempest (TM) game, be sure to correctly adjust the X and Y SIZE and CTR video pots on the Tempest Analog Vector-Generator (main) PCB [see text immediately above]. The instructions for these adjustments are printed on the Tempest schematics - Sheet 2, Side B - 3rd printing or later. Improper adjustment may cause the screen to go blank during normal game play.
Part No. Description (Reference Designations in parentheses) ========== =========================================================== 24-250107 100 uf Aluminum Elec. Fixed Axial-Lead 25V Capacitor (C1,2) 31-1N914 75V Type-1N914 Switching Diode (CR2-4) 32-1N751A 5.1V 400mW Type-1N751A Zener Diode (CR1) 33-2N3906 PCB Switching and Amplifying Transistor (Q2, 4, 5) 34-2N3904 Type-2N3904 NPN 60V 1-Watt Transistor (Q1, 3) 52-222 22-Gauge Jumper Wire (2 in. required) 110000-223 22K Ohm, +/- 5% 1/4 W Resistor (R1, 8, 11) 110000-273 27K Ohm, +/- 5% 1/4 W Resistor (R5) 110000-393 39K Ohm, +/- 5% 1/4 W Resistor (R4) 110000-682 6.8K Ohm, +/- 5% 1/4 W Resistor (R6, 7) 110001-222 2.2K Ohm, +/- 5% 1/2 W Resistor (R10) 110001-472 4.7K Ohm, +/- 5% 1/2 W Resistor (R9) 110011-122 1.2K Ohm, +/- 1% 1/4 W Metal-Film Resistor (R2, 3) [110000-102 1K Ohm, +/- 5% 1/4 W Resistor (R')]
INPUT PROTECTION CIRCUIT PCB ASSEMBLY
A038088-01 B
[Figure 1, a scale picture of the top side of the PCB listing numbered connection points onto the deflection board, has been omitted for obvious reasons]
Y INPUT +27V X INPUT
: : :
: *J6 :
: | :
: \ :
: CR1 / R1 :
: 1N751A \ 22K :
: 5.1V / :
: \ | :
: +--->|---+ :
: | \ | :
: R3 === | R2 :
: 1.2K = | 1.2K :
: 1% | 1% :
J3*--/\/\---*--->|---+---|<---*---/\/\--*J1
| J4: CR3 CR2 :J2 |
| : 1N914 1N914 : |
/ : : \
R5 \ To R601 1.6K 2% To R701 1.3K 2% / R4
27K / \ 39K
\ + C2 - - C1 + /
| 100 uf 100 uf |
| 25 V J5 25 V |
+-----|(-----+-----*-----+-----)|-----+
| | | | |
| | === | |
| R7 | = | R6 |
+----/\/\----+ +----/\/\----+
| 6.8K +27V 6.8K |
| : |
| *J6 |
| | |
| \ |
Q4 +-----+ Q3 R' / Q1 +-----+ Q2
2N3906| b |2N3904 1K \ 2N3904| b |2N3906
--- --- 1/4W/ --- ---
c / \ e / \ c | c / \ e / \ c
| | | +----------+----------+ | | |
| | | | | |
| | +--------------+--------------+ | |
| | | | |
| === \ / CR4 === |
| = --- 1N914 = |
| | |
+--------------------+--------------------+
| Q5 |
| 2N3906| b
| ---
| c / \ e
| | +------------------+
| +---------+---------+ |
| | | | |
\ \ \ \ |
/ R8 / R11 / R10 / R9 |
\ 22K \ 22K \ 2.2K \ 4.7K |
/ / / 1/2W / 1/2W |
| | | | |
J7*--------+ J9* *J8 *J5
: : : ===
-27V To D700 To D600 =
COLOR X-Y DISPLAY 92-053
INSTALLATION INSTRUCTIONS
INPUT PROTECTION CIRCUIT PCB
A038088-01
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[Figure 13, an annotated picture of the deflection board PCB from the original TM-183 manual, has been omitted for obvious reasons.]
[Since you will be making the board from scratch and don't have the pictures that came with the board, I am providing the following text to describe the contact points on the deflection board. The following text is all mine and NOT Atari's but is derived directly from figures 1 and 13 that Atari did provide.]
All descriptions refer to a deflection board oriented component side up with the board label "P314" at the top (right-side-up) and the 2 large electrolytic capacitors at the bottom. This orientation will have the electrolytics "side by side" and the board will be "taller" than it is "wide".
SPECIAL NOTE: According to the Major Havoc manual, this board came in 2 versions. Later versions had a 1K Ohm, +/-5%, 1/4 W resistor as one of the "stilts" on the board instead of a plain piece of wire. If your board does not have this resistor, here is what you need to do.
I have included this resistor in my ASCII rendering of the schematic and labeled it R'.
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[NOTE: Play Meter did copyright this article and the magazine is clearly marked with a copyright symbol.]
HOW TO MAKE A 'TEMPEST' MONITOR TROUBLE-FREE.
Atari's Tempest, when it is working, is not a bad game. It's just a shame that the monitors only last a few weeks (sometimes only days) between service calls. Most of the time, the monitor sits neglected on a techroom shelf.
Atari has developed a monitor protection board [included earlier in this text] to protect the monitor's components (2N3716 and 2N3792 "X" OUTput transistors, two each located on chassis frame) if and when there is a RAM lock-up on the Tempest CPU board. I want to clarify that the Wells-Gardner monitor is not at fault. Also note that on the later Atari games, the protection circuit has been incorporated into the board circuitry. [These statements seem to imply that this "fix" is compatible with the Atari upgraded P314s as well as P327s and P339s and will provide additional protection; if fact, I have seen it on a P327 before. It is sufficiently ambiguous that the exact opposite can be inferred. Judging from the areas of the board it alters, I would say it is incompatible (duplicates) the other fixes in this section.]
It's common knowledge that you can purchase a broken Tempest game cheap. With about 20 minutes of your time and a couple of dollars in parts, it is possible to add just six common components to the monitor deflection board and have a Tempest that will stay on location and work [Yeah, right]!
The parts required are:
ANODE +------+-+ CATHODE
+--------+1N4737| +--------+ GROUND
CATHODE +-+------+ ANODE / +------+-+ |
--------+ | 1N914+--------+ === C700
R700 +-+------+ \ +--------+ |
+--------+ 1K ohm +--------+ -27 VOLTS
+--------+
Locate C700 in the top left of the monitor deflection board. (See Figure 13 on page 20 of Atari TM-183 Wells-Gardner Quadrascan service manual; second printing) and solder the cathode of the 1N4737 to the ground side of C700 (right side in Figure 13). Solder the end of the 1K OHM resistor to the -27 volt side (left side) of C700. Solder the one remaining wire (the cathode of 1N914) to the "X" INput side of R700 (top end of R700). You are now halfway finished.
ANODE +------+-+ CATHODE
GROUND +--------+1N4737| +--------+
| +------+-+ \ CATHODE +-+------+ ANODE
C701 === +--------+ | 1N914+--------
| +--------+ / +-+------+ R700
+27 VOLTS +--------+ 1K ohm +--------+
+--------+
Locate C701 (top middle in Figure 13) and solder the anode of 1N4737 to the ground side of C701 (right side). Solder the end of the 1K OHM resistor to the +27 volt side of C701 (left side). Go back to the same "X" INput side of R700 and solder the remaining wire (the anode of the 1N914) to this connection. Make sure that you have a good solder connection at the "X" INput of R700 as you now have a three-wire joint.
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Cut the trace just to the left of pin 3 of P101 isolating the 5 rightmost connections (F700, R808, pin 5 of P701, C104, and R712) from the rest of the cluster. Jumper the 5 isolated connections to pin 1 of P100. This makes those 5 connections run at 33.8V instead of the usual 27.8V.
I am not sure what is gained by biasing these portions of the circuit by larger magnitude voltages but will look into it later.
When I saw this next hack, I couldn't believe my eyes; especially after I plugged it in and IT WORKED! The hack described above was implemented but with the following additions...
Evidently this operator got so tired of fixing the low voltage power supply regulator circuitry that he ELIMINATED IT FROM THE CIRCUIT! What he did was remove virtually that entire section (R100-103, D104-105, and P100) and instead formed the voltages required by dropping the unregulated +/-33 voltages across resistors! He connected a 10 Watt, 25 Ohm (+/- 10%) resistor between pins 3 and 7 of P100. An identical resistor was connected between pins 1 and 4 of P100. I'm not sure what kind of solder he used but it is takes a good minute for a 30 Watt soldering iron to even begin to melt a small portion of it.
This change will give you a very noisy approximation of the original voltages that should be good enough to run the monitor. Needless to say, the ceramic resistors get unbelievably hot and the screen is a little jumpy when drastic changes in drawing (current pull) occur (such as between waves and during the demo) but other than that the results are quite tolerable. If run for extended periods, this setup is virtually guaranteed to blow some fuses on the deflection board.
Since there is no longer a Q101 to worry about, it won't cause you any problems and since P100 no longer exists (either it or the connector that goes to it should be removed to avoid somebody plugging it in and adding the transistors to the now foreign circuit), there won't be any problems with Q102 and Q103 either (they are no longer required in the circuit and the connector that went on the now missing P100 just hangs in the air). If you are going to be placing one of these monitors out in the field or it is going to get frequent, extended duration use, this hack MIGHT be worth trying (assuming the degradation of picture quality is acceptable to the viewers) but I would think it would greatly stress the rest of the circuitry as well as the yoke coils and would limit the lifetime of the unit in other, less familiar ways. The PCB I saw this on had extensive burns on the amplification portions of the circuit which I almost never have to repair so BEWARE; this hack may have been the cause not the solution!