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Most VCR problems will be limited to a specific subsystem - video, audio, tuner, servo, control. When multiple seemingly unrelated problems occur at the same time, suspect a power supply problem since multiple systems may be fed from common power supply outputs. There are always several different voltages used within a VCR - if one of these dies, some subsystems will work but will not receive the proper signals from the dead parts. So, nearly any kind of behavior is possible. Therefore, the first test is to determine, if possible, that the power supply outputs voltages are correct - both with power off and power on.
Power supply problems can range from intermittent behavior due to slightly out of tolerance voltages, hum, or noise to a totally dead VCR. Multiple system failures can result if one or more of the half dozen or so voltages used within the VCR are incorrect or missing. Some power supply problems are caused by power surges. These may result in a totally dead VCR or in overstress and subsequent failure of various components. A power strip with a circuit breaker, even with surge protector is not a reliable protection against power surges especially during lightning storms. The only sure protection is unplugging electronic equipment during storms - but then, what would your insurance agent have to do?
A variety of protective devices are used in VCRs. Of course, where the VCR is stone dead, check for a blown line or secondary fuse in the power supply. Occasionally, a fuse will blow due to a power surge or for no good reason and a new fuse is all that is needed. However, this is usually not the case and a new fuse will blow immediately. There is a chance that additional damage may result - proceed cautiously. If the fuse element is vaporized - black or silver coating on the glass, a short in the power supply is likely. However, a violent surge on the power line can also result in such a symptom. Various subsystems of the VCR may be protected by individual fuses as well. Sometimes, one of these will blow resulting in a variety of multiple systems problems but not a totally dead VCR. Look for fuses on the mainboard as well as the power supply. IC Protectors (ICPs) may be present on a single chip or small subsection of a circuit. Most common types are miniature fast acting fuses. Typically, they come in a black TO92 or rectangular .1"x.3" plastic case with two leads. Test these like a fuse - an IC protector should be a short if good. In some cases you may find a PTC (Positive Temperature Coefficient resistor - resistance increase dramatically due to excessive current heating the element) type of fuse or IC protector - these are self resetting once the overload has been removed. However, this also means that testing with power off will show low resistance even if a fault still exists (unless you test immediately). Measuring voltage across such a device with power on is one way of identifying a problem. One common form of this device appears as a little metal metal sandwich - the two plates are separated by the active material.
Reread Safety info before tackling any power supply problem in a VCR! VCRs typically use one of four types of power supplies (There are no doubt others): 1. Power transformer with linear regulator using 78/79XX parts or discrete components. The power transformer will be large and very near the AC line cord. 2. Power transformer with hybrid regulator like STK5481 or any of its cousins - multioutput with some outputs switched by power on. If it has one of these, check ECG, SK, or NTE, or post to sci.electronics.repair and someone can probably provide the pinout. Again, the power transformer will be large and very near the AC line cord. 3. Small switching power supply. Most common problems: shorted semiconductors, bad capacitors, open fusable resistors. In this case there is usually no large power transformer near the line input but a smaller transformer in a more central location. 4. Combo of the previous - these are less common. An input power transformer may supply low voltage to a switcher. 5. Camcorders and portable video camera-VCR combos include a battery charger and run all normal VCR (and camera) functions off of the battery. The required voltages are derived using DC-DC inverters. Here are some general comments for each type: 1. Troubleshooting is quite straightforward as the components are readily identified and it is easy to trace through from the power transformer, bridge or centertapped full wave rectifiers, regulators, caps, etc. The circuitry is not usually complex and the most common failures tend to be quite obvious. It should be possible to determine the correct output voltages from basic circuit principles. 2. Failures of one or more of the outputs of these hybrid regulator blocks are very common. Use ECG/STK/NTE cross reference to identify the correct output voltages. Test with power switch in both positions. Any significant discrepancy indicates a likely problem. While an excessive load dragging down a voltage is possible, the regulator is the first suspect. See: "VCR Power Supply Regulators" for pinouts of some of the common ones. The correct output voltages will be specified by on the regulator pinout. Replacement cost is usually under $10. 3. Switching supply problems are tougher to diagnose but it is usually possible without service literature by tracing the circuit and checking for bad semiconductors with an ohmmeter. Common problems - dried up capacitors, shorted semiconductors, and bad solder joints. In a supply that is dead - has blown the main fuse - check **all** semiconductors, capacitors, and resistors as a failure in one may damage others and just replacing the first one you find that is bad may result in it just blowing immediately. Fusable (flameproof) resistors (blue or brown body or boxy ceramic power type) may open up if there was a shorted switching transistor. Power resistors supplying current for the startup circuit may open from age. See the document: "Notes on the Troubleshooting and Repair of Small Switchmode Power Supplies" for more detailed information. Correct output voltages can be determined with some work - tracing the circuit. However, it is usually safe to assume that there should be at least one around 5 to 6 V for the logic and one or more others at 12 V or higher for the motors and other electronics. 4. Problems in either the power transformer/rectifier/filter capacitor section (usually no regulator) or switching supply are possible. However, they can pretty much be dealt with independently. Note: the switching supplies used in these usually run off of a lower voltage input than the more common off-line non-isolated type making them somewhat less hazardous to your health to work on. 5. Problems can occur in either the battery charger or power supply section. Short running time on battery alone is usually caused by a bad battery. If possible, try a known good battery or battery eliminator first to determine which it is. The older style portable units were quite reliable and easy to service. However, modern camcorders are so jam packed with microminiature surface mount unmarked circuitry that troubleshooting and repair is definitely not fun. Not to mention the joys of just getting inside with only a finite use of expletives. Don't overlook the possibility of bad solder connections as well.
Power surges or nearby lightning strikes can destroy electronic equipment. However, most of the time, damage is minimal or at least easily repaired. With a direct hit, you may not recognize what is left of it! Ideally, electronic equipment should be unplugged (both AC line and phone line!) during electrical storms if possible. Modern TVs, VCRs, microwave ovens, and even stereo equipment is particularly susceptible to lightning and surge damage because some parts of the circuitry are always alive and therefore have a connection to the AC line. Telephones, modems, and faxes are directly connected to the phone lines. Better designs include filtering and surge suppression components built in. With a near-miss, the only thing that may happen is for the internal fuse to blow or for the microcontroller to go bonkers and just require power cycling. There is no possible protection against a direct strike. Most VCRs have their own internal surge protection devices like MOVs (Metal Oxide Varistors) after the fuse. So it is possible that all that is wrong is that the line fuse has blown. Remove the case (Unplug it first!) and start at the line cord. If you find a blown fuse, remove it and measure across the in-board side of fuse holder and the other (should be the neutral) side of the line. With the power switch off, this reading should be very high. With the switch on, it may be quite low if the VCR uses a large power transformer - a typical primary resistance is 15 to 30 ohms. Some VCRs may be outside this range but if the reading is extremely low, the power transformer could have a partially or totally shorted primary. If it is very high (greater than 1 K ohms), then the primary of the power transformer may be open or there may be blown thermal fuse under the insulation wrappings of the transformer windings. If the VCR has a switching power supply, see the document: "Notes on the Troubleshooting and Repair of Small Switchmode Power Supplies". If the resistance checks out, replace the fuse and try powering the unit. There will be 3 possibilities: 1. It will work fine, problem solved. 2. It will immediately blow the fuse. This means there is at least one component shorted - possibilities include an MOV, line filter capacitor, transformer primary. 3. It will not work properly or still appear dead. This could mean there are blown fuses or fusable resistors or other defective parts in the power supply or other circuitry. In this case further testing will be needed and at some point you may require the schematic.
Should you always use a surge suppressor outlet strip or line circuit? Sure, it shouldn't hurt. Just don't depend on these to provide protection under all circumstances. Some are better than others and the marketing blurb is at best of little help in making an informed selection. Product literature - unless it is backed up by testing from a reputable lab - is usually pretty useless and often confusing. Line filters can also be useful if power in you area is noisy or prone to spikes or dips. However, keep in mind that most well designed electronic equipment already includes both surge suppressors like MOVs as well as L-C line filters. More is not necessarily better but may move the point of failure to a readily accessible outlet strip rather than the innards of your equipment if damage occurs. It is still best to unplug everything if the air raid sirens go off or you see an elephant wearing thick glasses running through the neighborhood (or an impending lightning storm). Generally, the backup battery or supercap will retain the clock and programming information long enough to ride out a typical storm.
The front panel clock, counter, and function indicators on most VCRs use something called Vacuum Fluorescent Display (VFD) technology. The VFD uses a vacuum tube which includes a heated filament and multiple phosphor coated anodes in the shapes of the letters, words, and symbols. A positive voltage on selected anodes cause electrons to stream from the filament causing them to glow. * The filament is in the form of a few fine wires running across the entire face of the display. Typical voltage is 4 to 6 V AC or DC depending on design. It may be possible to see a faint glow from the filament in a darkened room but the front panel will probably need to be removed to do this since its plastic filter is likely to block much of the the orange light from the filament. * The voltage for an 'on' anode is generally between 20 and 30 V positive with respect to the filament. Problems with a dim or dead display can be due to a lack or fault with one of these power sources, the drive logic (system controller), or bad connections. With some VCRs, a special DC-DC converter is used to drive ONLY the display and this a common failure item. See the section: "Dead clock in Hitachi manufactured VCR". Where the display works but is dim, there can be several causes: * Some VCRs have a 'night mode' which dims the display after, say, 10:00 PM. Check that you don't have the clock AM and PM set incorrectly. There is usually a way to disable this 'feature'. * If the VCR has been used in a location where there are heavy smokers, whatever tar and nicotine somehow avoided getting trapped in their lungs may have been deposited on the front and rear surfaces of the plastic display window and on the front of the display tube. Remove the front panel and use alcohol and a soft cloth to thoroughly clean all these surfaces. * The VCR may have seen a long active life. Like CRTs and other vacuum tubes, cathode emission and/or phosphor brightness can degrade over time. There is nothing much that can be easily done to remedy this. * The filament or anode voltage may be low or faulty due to a bad connection, dried up electrolytic capacitor, or other power supply problem.
What could be the cause of the video dying on a VCR after it is playing for a couple of hour? Here are some questions: Do all modes 'go out' or just PLAY? Does it happen suddenly or just gradually worsens until it is total snow? Or, do you get the 'blue screen' if it has this function rather than snow? Does the tuner still work? Conversely, does PLAY work but not the tuner? Do other functions like FF and REW always work? How is the time it sits turned off related to how much on time you get? Have you verified that the TV is fine? Is it possible that the VCR is covered up/closed in/installed with inadequate ventilation? It could be a loose connection or bad component. The usual way to narrow down the possibilities is to use what is called 'cold spray' or 'circuit chiller' on the appropriate sections of the circuit board until you locate the component that is failing with when it gets hot. I once had a VCR that needed a little fan blowing on it to keep it happy - much easier solution than actually hunting down the fault. If play or record just stopped and the tape unloaded, it could also be a mechanical problem like a marginal idler tire, idler clutch, or worn belt.
These are the kinds of problems that put gray hairs on parts of your body you didn't think could grow hair (hey, maybe that is good). First confirm that the correct fuse type and value was used for this particular model and revision number. Of course, measurements of the supply current on the bench show a wide safety margin (i.e., 2:1). I don't suppose there was any mention of what was being done when it stopped working? While monitoring the current, try really exercising the FF and REW, switching between editing/tape movement modes, performing FF and REW to the end of tape stops, etc. These are where I would expect to see current spikes. It may be some peculiar combination of actions that results in a momentary jam or conflict. Unless of course it is just some cosmic connection that takes place every 3 months!
So your cat decided it was time to practice the long-jump and didn't quite pick a stable destination. Your VCR is on the floor, Tabby is in the basement, and what to do? Overall, VCRs are quite tough. However, falling in just the wrong way can do substantial and possibly not immediately visible damage. If you take it in for service, the estimate you get may make the national debt look like pocket change in comparison. Attempting to repair a VCR that has been dropped is a very uncertain challenge - and since time is money for a professional, spending an unknown amount of time on a single repair is very risky. There is no harm is getting an estimate (though many shops charge for just agreeing that what you are holding is a VCR!) This doesn't mean you should not tackle it yourself. There may be nothing wrong or very minor problems that can easily be remedied. First, unplug the VCR even if it looks fine. Until you do a thorough internal inspection, there is no telling what may have been knocked out of whack or broken. Electrical parts may be shorting due to a broken circuit board or one that has just popped free. Don't be tempted to power the VCR even if there are no obvious signs of damage - turning it on may blow something due to a shorting circuit board. Then, inspect the exterior for cracking, chipping, or dents. In addition to identifying cosmetic problems, this will help to locate possible areas to check for internal damage once the covers are removed. Next, remove the top and bottom covers and front panel. Check for mechanical problems like a bent or deformed cassette basket, broken or cracked plastic parts, and anything that may have shifted position or jumped from its mountings. Carefully straighten any bent metal parts. Replace parts that were knocked loose, glue and possibly reinforce cracked or broken plastic. Plastics, in particular, are troublesome because most glues - even plastic cement - do not work very well. Using a splint (medical term) or sistering (construction term) to reinforce a broken plastic part is often a good idea. Use multiple layers of Duco Cement or clear windshield sealer and screws (sheetmetal or machine screws may be best depending on the thickness and type of plastic). Wood glue and Epoxy do not work well on plastic. Some brands of superglue, PVC pipe cement, or plastic hobby cement may work depending on the type of plastic. Cycle the cassette loading and tape loading mechanism manually by turning the appropriate motor shaft, if possible. Check for free movement of the various parts of the tape transport. Inspect for any broken electronic components - these will need to be replaced. If the fluorescent panel is broken, you can run the VCR without it but of course will not be able to see any front panel displays. Check for blown fuses - the initial impact may have shorted something which then blew a fuse. There is always a slight risk that the initial impact has already fried electronic parts as a result of a momentary short or from broken circuit traces and there will still be problems even after repairing the visible damage and/or replacing the broken components. Examine the circuit boards for any visible breaks or cracks. These will be especially likely at the corners where the stress may have been greatest. If you find **any** cracks, no matter how small in the circuit board, you will need to carefully inspect to determine if any circuit traces run across these cracks. If they do, then there are certainly breaks in the circuitry which will need to be repaired. Circuit boards in VCRs are never more than two layers so repair is possible but if any substantial number of traces are broken, it will take a great deal of painstaking work to jumper across these traces with fine wire - you cannot just run over them with solder as this will not last. Use a fine tipped low wattage soldering iron under a magnifying lens and run #28-30 gauge insulated wires between convenient endpoints - these don't need to be directly on either side of the break. Double check each connection after soldering for correct wiring and that there are no shorts before proceeding to the next. If the circuit board is beyond hope or you do not feel you would be able to repair it in finite time, replacements may be available but their cost is likely to be more than the VCR is worth. Locating a junk VCR of the same model to cannibalize for parts may be a more realistic option. Once all visible damage has been repaired and broken parts have been replaced, power the VCR up and see what happens. Be prepared to pull the plug if there are serious problems (billowing smoke would qualify). Determine if it appears to initialize correctly - without shutting down. Play a garbage tape to determine if there are any problems that might damage the tape. Watch and listen carefully for any evidence of poor tracking, video noise, tape speed instability, or weak or muddy audio that might indicate that tape path alignment requires further attention. Listen as well for any unexpected mechanical sounds that were not there before. Very likely, the VCR will be fine, you can replace the covers, and now find a more secure spot for it to prevent this sort of event in the future. Use your own judgment with respect to the cat.
Someone took your camcorder to the beach this summer and now it has sand or perhaps salt inside. Or, that cup of tea on top of the VCR wasn't as stable as you thought. Now, it behaves, well, strangely. Can this possibly be fixed? Will it be worth the effort or expense? Unless this is a really sophisticated (i.e., costly) unit, I doubt whether it will pay you to take it anywhere for repair. Even if it is successfully repaired, its reliability may be questionable. Furthermore, as with equipment that has been dropped or physically abused, few repair shops will be inclined to touch the job. They really don't like challenges of this sort. That leaves you! If anything got wet with saltwater and it has been just sitting, you can probably forget it. Without immediate attention (and I mean immediate, not later, not tomorrow, NOW!), saltwater corrosion can set in very quickly and attacks electronic components, circuit board traces, cable wiring, and mechanical parts. The only thing worse might be a peanut-butter-and-jelly sandwich 'played' in your VCR. On second thought, that probably would not be all that bad. Although it is probably too late, the first thing to do when electronic equipment gets wet is to remove the power source - pull the plug or remove the batteries. Don't be tempted to apply power until you have determined that everything is completely dried out inside and out. DO NOT use strong solvents anywhere! These may attack various plastic parts or cause internal damage to electronic components. The following was written assuming sand, salt, and liquid contamination everywhere! Modify based on your specific situation. Mechanical intensive care: 1. Disassemble as much as possible - sand and surf (or other liquids) find their way into the tiniest nooks and crannies. You need to get it all. 2. Make a drawing of the belt routing, remove the belt(s), wash and dry them, label and set them aside. 3. Use a soft brush (like a paintbrush) to dust out as much sand as possible. Hopefully, you can get it all this way. A vacuum cleaner with a wand attachment may prove handy to suck out sand. Sand will tend to collect on lubrication, especially grease, which will need to be completely cleaned out and replaced. Don't use high pressure compressed air, you will just spread it around. Any grease or oil on which sand has collected will need to be totally removed and replace with fresh lubrication. 4. If there is evidence of salt (remember, I said forget it...but), you will need to wash it off. Yes, wash it. Keep water out of the motors. Use low pressure compressed air (a blow dryer on low heat should be fine) to dry so that it does not rust. Ditto if it is still wet with contaminated liquid (we won't say where this came from), wash with fresh water to remove all traces of it as quickly as possible. Then dry completely. Depending on the situation, a final rinse with 91% or pure isopropyl alcohol may be desirable to decrease drying time. This should be safe for most mechanical assemblies. Degreaser may be used if it is safe for plastic and rubber parts. Lubricate all bearing points with a drop of light machine oil - electric motor oil, sewing machine oil, etc. (Never never never WD40). Lubricate gears, cams, and sliding parts with a light plastic safe grease such as Molylube. Parts like the idler clutch may need to be disassembled to get at the friction felt. Other mechanical parts like cam gears may need to be removed to be properly cleaned. Don't mess up the timing relationships when you do this! 5. Reinstall the belts and reassemble in reverse order. Electronic intensive care: 1. Remove the circuit boards and label the connectors if there is any possibility of getting them mixed up. If the circuit board(s) are soldered to the rest of the equipment, then you will have to improvise and work in-place. 2. Wash with water and dry thoroughly. This does work. I use it routinely for degunking remote controls and rubber membrane keypads, for example. I have heard of people cleaning contaminated computer keyboards in their dishwasher! The important objective should be to get corrosive liquids off the components and circuit traces as quickly and completely as possible. A final rinse with 91% or pure isopropyl alcohol will decrease drying time. However, there is a slight risk of damage to sensitive electronic components should some be trapped inside. Pat dry, then use warm air from a hair dryer (or heat gun on low) to completely dry everything. Moisture will be trapped in controls, coils, selector switches, relays, transformer cores, connectors, and under large components like ICs. DO NOT operate until everything inside and out is thoroughly dry. 3. Use spray contact cleaner on the switches and control cleaner on the control and adjustment pots. DON'T turn the internal adjustments without precisely marking the original position - else realignment will then be needed. However, exercise the user controls to help the cleaning process. Note: drying time may be quite long. For parts with inaccessible areas like membrane keypads, you may need to wait a week before normal operation is restored. Be patient! Once everything is completely dry as a bone and reassembled, power it up but be prepared to pull the plug or pop the batteries if there are serious problems See if the display comes alive and the transport appears to initialize. Attempt to play a garbage tape to determine if there are any mechanical problems that might damage the tape. Look and listen for any abnormalities which may require additional attention. Then address specific problem areas. Also see the section: "VCR was dropped" for additional info. Obviously, this description is very simplistic. The important thing is to get every last grain of sand, salt, and other contaminants off of the mechanisms and circuit boards quickly. As noted above, moisture may collect inside certain electronic parts and it is essential that these be dried completely before attempting to apply power to the unit. If you do not, at best it will not work properly and you may do additional serious damage due to short circuits. For the mechanics, the same applies though this is trickier since certain parts need to be lubricated and these may not be readily accessible or obvious. Don't be tempted to overdo the lubrication - too much is worse than too little. For camcorders, some parts of the optics or enclosed DC-DC converters may be impossible to access and clean of scum.
See the document: "Notes on the Troubleshooting and Repair of IR Remote Controls" for extensive information as well as links to the web sites of manufacturers of universal remote controls - these include setup info.
So you just pulled your favorite tape from the VCR and there are two tape ends dangling from it. Or, perhaps, your VCR has just munched on that tape and a section is now seriously crinkled. Maybe you haven't been following the recommendations on preventive maintenance; maybe your VCR was just hungry. In any case, what to do? The recording is, of course, irreplaceable. Despite this, I recommend you chuck it. An imperfect splice or seriously crinkled section of tape can shatter your video heads - the most expensive single part in a VCR. If it is something you really treasure, than what I would do is the following: Note: If you have never seen the inside of a video cassette, try the following on a couple you really don't care about first so that if you screw up, there is no great loss. Too bad AOL doesn't send out Internet software on video cassettes, huh? CAUTION: The video tape itself is really really thin and easily crinkled. Be very gentle when handling it and avoid touching the oxide (dull side) if at all possible. 1. Locate a garbage cassette and disassemble it. Throw away the tape but save everything else including the reels. See the section: "Disassembling a VHS cassette". 2. Construct two cassettes from the combined collection of parts you now have. Cut out any sections of tape that got mangled. Cassette 1 has the first section of tape (before the break) and uses one empty reel from the garbage cassette for the supply reel. Rewind this to the beginning. Cassette 2 has the second section of tape (after the break) and uses the other empty reel from the garbage cassette for the takeup reel. Use the little plastic plugs that came from the garbage tape reels or some adhesive tape to connect the tape to the reels. 3. If the break is at one end, you can just reconnect the bulk of the tape to the reel and dispose of the original leader. Just don't rewind or fast forward all the way to the end as the automatic end sensor will not work (for the particular end that has been repaired). What will happen is that instead of the sensor stopping REW or FF (as appropriate), the tape will run to the end and the VCR will then shut down when it discovers that the tape isn't moving. This can put additional stress on mechanical parts and/or rip the tape from the reel. Serious damage to the VCR isn't really that likely. 4. Copy to a good cassette. 5. Dispose of the original(s) or clearly mark 'DO NOT USE' with a detailed explanation.' Filip (I'll buy a vowel) Gieszczykiewicz (filipg@repairfaq.org) is a little more definitive about this: "I find the destruction of it more fulfilling :-) ... put it in a paper bag and smash the life out of it with a big, heavy hammer - or a small ball hammer for an even higher satistfaction ratio :-) " The idea is to never have a splice in a VHS cassette. (Even a seriously crinkled tape such as might result from a tape eating incident can damage the heads.) It is possible to splice safely but as noted, it can be quite costly if you don't get it quite right.
These instructions should enable you to get inside a cassette for the purpose of reattaching a leader that pulled off of one of the reels or to enable you to transfer its contents or a portion thereof to another shell or vice-versa. 1. Peel off the label on the side or carefully slice down its center line with a knife or razor blade. This is necessary to allow the cassette halves to be separated. 2. Place the cassette upside-down and remove the five (5) phillips head screws and set aside. 3. While holding the cassette together, place it label side up on a clean surface. 4. Gently remove the top (along with the hinged door) to reveal the interior. At this point, you should see something that looks like VHS Cassette - Inside Top View. When you reassemble the cassette, take care to avoid crunching the tape under the hinged door - depress the unlock button on the side and lift it clear if needed.Go to [Next] segment
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