[Mirrors]
Atari Vector Monitor Repair/Upgrade
Contents:
Perform the following procedure to modify the Deflection PCB (see
Figures 6 and 7).
- Set the display on a clean work surface.
- Disconnect the 15-pin Molex connector from the mounting bracket
on the display chassis and the harness connectors from the
Deflection PCB and the Neck PCB.
- Use a 1/4-inch hex driver to remove the two screws securing the
Deflection PCB to the display chassis [NOTE: there are holes for
2 more screws in the remaining (rear) 2 corners of the board
which some users decided to fill; if the board won't come out,
check for this]
- Remove the Deflection PCB from the display.
- Connect two type-1N754A Zener diodes together, anode to anode,
as shown in Figure 6. Use a soldering iron to solder the two
anode leads together.
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.]
- Connect two type-1N756A Zener diodes together and solder as
described in step 5.
- Examine the soldered side of the Deflection PCB removed from the
display and determine which of the two PCBs shown in Figure 7
matches your PCB.
- On the component side of the Deflection PCB, locate the yellow
wire (top right side of the PCB).
- Solder one cathode lead of the two type-1N754A Zener diodes
(soldered together in step 5) to the yellow lead on the soldered
side of the PCB as shown in the appropriate illustration in Figure 7.
- Solder the other cathode lead of the two type-1N754A Zener diodes
to ground as shown on the appropriate illustration in Figure 7.
- On the component side of the Deflection PCB, locate the orange
wire (near top center of the PCB).
- Solder one cathode lead of the two type-1N756A Zener diodes
(soldered together in step 6) to the orange lead on the soldered
side of the PCB as shown on the appropriate illustration in Figure 7.
- Solder the other cathode lead of the two type-1N756A Zener diodes
to ground as shown on the appropriate illustration in Figure 7.
- On the component side of the Deflection PCB, locate connector
P600 (right center of the PCB).
- Solder the cathode lead of a type-1N4002 diode to pin 1 and the
anode lead to pin 4 of connector P600 on the soldered side of the
PCB as shown on the appropriate illustration in Figure 7.
- Solder the cathode lead of a type-1N4002 diode to pin 5 and the
anode lead to pin 7 of connector P600 on the soldered side of the
PCB as shown on the appropriate illustration in Figure 7.
- On the component side of the Deflection PCB, locate connector
P700 (left center of the PCB).
- Solder the cathode lead of a type-1N4002 diode to pin 1 and the
anode lead to pin 4 of connector P700 on the soldered side of the
PCB as shown on the appropriate illustration in Figure 7.
- Solder the cathode lead of a type-1N4002 diode to pin 5 and the
anode lead to pin 7 of connector P700 on the soldered side of the
PCB as shown on the appropriate illustration in Figure 7.
- Refer to Table 3 to determine which of the four versions of the
display has been installed in your Tempest game.
Table 3 Display Versions
- Version 1
-
Deflection PCB has two large, black, tubular capacitors,
C804 and C805, installed below top center of PCB.
[NOTE: These are 1" long and .25" in diameter and are
radial lead type; I guess as far as PCB components go,
they could be considered large but as far as
electrolytics go, they are rather small. As far as I
know, these are present only on versions P327 and P339
of the Deflection PCB (which have the Input Protection
Circuit redesigned into the board). This question could
probably more easily be phrased, "Is your board labeled
P327 or P339." The fact that they chose not to word the
question this way implies that there are some board
redesigns which were labeled P314 instead of P327. The
proceeding 3 descriptions refer only to (most but
perhaps not all of) the various flavors of the P314
version of the Deflection PCB (i.e. not P327 nor P339).]
- Version 2
-
Input Protection Circuit PCB is installed (piggyback)
WITH A 1K Ohm, +/-5%, 1/4 W RESISTOR CONNECTED BETWEEN
THE INPUT PROTECTION CIRCUIT PCB AND THE DEFLECTION PCB.
[NOTE: I have documented this PCB immediately following
this article.]
- Version 3
-
Input Protection Circuit PCB is installed (piggyback)
BUT DOES NOT HAVE A RESISTOR CONNECTED BETWEEN
THE INPUT PROTECTION CIRCUIT PCB AND THE DEFLECTION PCB.
- Version 4
-
Deflection PCB DOES NOT HAVE CAPACITORS C804 AND C805
(BELOW TOP CENTER OF PCB) OR AN INPUT PROTECTION
CIRCUIT PCB INSTALLED.
- Perform the procedure as follows for the appropriate version of
the display determined from Table 3. (Refer to the display
manual, TM-183, for component and connector locations).
NOTE:
The 30Kohm, 1/4W resistor supplied in the kit is
used only for Version 1 of the Wells-Gardner display.
Perform the following procedure for Version 1 of the Wells-Gardner display.
- Verify that the Preliminary Procedure has been performed.
- Use a soldering iron to remove resistor R811 and replace it
with the 30Kohm, 1/4W resistor supplied in the kit.
- Use a 1/4-inch hex driver to secure the modified Deflection PCB to the display chassis.
CAUTION!: Make certain that the harness from Q705 and
Q706 is connected to P700 and not P100.
- Connect the harnesses to the appropriate Deflection PCB connectors.
Perform the following procedure for Version 2 of the Wells-Gardner display.
- Verify that the Preliminary Procedure has been performed.
- Use a 1/4-inch hex driver to secure the modified Deflection PCB to the display chassis.
CAUTION!: Make certain that the harness from Q705 and
Q706 is connected to P700 and not P100.
- Connect the harnesses to the appropriate Deflection PCB connectors.
Perform the following procedure for Version 3 of the Wells-Gardner display.
- Verify that the Preliminary Procedure has been performed.
- Locate the wire connected to resistor R1 (22K ohm) and the
collectors of transistors Q1 and Q3 (type 2N3904) on the Input
Protection Circuit PCB and the point shown in Figure 7 on the Deflection PCB.
- Use a wire cutter to cut the wire, located in step 2, half-way
between the two PCBs.
- Use a soldering iron to solder a 1K Ohm, +/-5%, 1/4 W resistor
(not included in the kit) between the two ends of the wire cut in step 3.
- Use a 1/4-inch hex driver to secure the modified Deflection PCB
to the display chassis.
CAUTION!: Make certain that the harness from Q705 and
Q706 is connected to P700 and not P100.
- Connect the harnesses to the appropriate Deflection PCB connectors.
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.
- Verify that the Preliminary Procedure has been performed.
- Install the Input Protection Circuit PCB to the Deflection PCB as
described in the instructions supplied with the Input Protection
Circuit PCB assembly.
- Use a 1/4-inch hex driver to secure the modified Deflection PCB
to the display chassis.
CAUTION!: Make certain that the harness from Q705 and
Q706 is connected to P700 and not P100.
- Connect the harnesses to the appropriate Deflection PCB connectors.
====================STOP=====================
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:
====================START====================
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.
====================STOP=====================
====================START====================
[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.]
NEW INPUT PROTECTION CIRCUIT FOR WELLS-GARDNER COLOR X-Y DISPLAY
(Supplement to TM-183)
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.
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