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Hi, I am working on a JVC TV AV-56WP74. It has a convergence problem on the screen, I took the convergence board off the set. I checked all the resistors,diodes and some transistors around the IC's (stk392-110) and there are no faulty components on it. I am gonig to replaced the two IC's to see if the problem is solved, but is there anything alse I need to check on other circits to make sure that was the only faulty components cause the problem to occurred? Any help is going to be really appreciated.Thank you

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Http://www.retrevo.com/support/JVC-AV-56WP74-TVs-manual/id/279dj189/t/2/

Above is your user manual, below is your service and repair manual.
http://www.fixdevice.com/smanuals/file/45772.html
IF you wish to try to fix it yourself, and I do not recommend it. FIRST, you Must get a service manual, then you need, equipment, an Oscilloscope is a MUST HAVE. Also a Multimeter, and soldering iron, a DE-soldering station, an anti-static wrist strap, (Any TV is extremely static sensitive). Now FIRST you must make sure the Power supply is 100% as if this is NOT then nothing else can be. Also there are safety considerations, any unit that can cause a Fire or Explosion, or both, needs to be attended to with the utmost care. As if it isn't done correctly, a catastrophe is indeed possible, Faulty sets can cause a fire, and a fire in the middle of the night, I believe is not good. And any person that has attended that set, will be held to account. Now with that understanding, I guess proceed if you wish. Troubleshooting say if it is shutting down, after a certain amount of time, of working and then faulting, then it is most definitely a "Thermal" problem, the way we "Find" problems such as this is "Freeze Spray" you use this on each component that is suspected of being the "Culprit" and you will soon,find that errant component. Now also not every fault is a Capacitor, I see many, many people that think, that Capacitors are always the "Culprit" now while that may be true in a few cases, a faulty Electrolytic Cap, or ordinary, Cap goes faulty, this is only a SYMPTOM, something has damaged those caps causing them to "Fail". One MUST always find the root "Cause", otherwise if you just treat, the SYMPTOM, the "Cause" will just make the "Symptom" come back, in short order, as the prime cause still, hasn't been fixed., Now Capacitors hate AC ripple, or Over Voltage. Thats it. Oh.. and Heat, if these Capacitors, are too close to a Heat Source, then thats a prime cause of failure. Resistors, hardly ever go faulty,and if they do, it is generally obvious. However it doesn't hurt to check values with our Multimeter. Remember though resistors are made, with up to 20% tolerance from stated value, as such, are not too critical, unless in Timing circuits etc. Always check, the Values, of resistors, as with any other component, with the power OFF. Now Diodes especially "Zener Diode", are another thing to check, those and ordinary "Signal Diode" should always be suspect. next we have Transistors and IC's. The Transistors MUST ALL be checked to see if they have a good, "Junction" this is done, with our meter set to "Diode Test" and usually are about 0.6 to 0.7. With IC's you must check, voltage levels, or Logic Levels, going in and out, have a look at the circuit diagram, and it will tell you what they should be. It is a good idea to always measure the Power Supply voltages, see if a "Rail" is Low, that will be because some component has gone somewhat or all short circuit, to Earth, now, if the "Rail" is Higher, suspect an "Open Circuit" component, like a Diode, or Transistor. The voltages expressed in the manual are spot on, ANY variation MUST be investigated. I have been doing all this for over 30 years now, and I do indeed wish, we could have a set of "Symptoms" and be ables to say.. "Oh that;s the so-in-so and replace this" however unfortunately this although does happen, most "Symptoms" can have literally tens, of "Causes" all often "Interlinked" One simply has to do a methodical troubleshooting procedure, and always think, "are my Voltages Correct" as this is how, you Fix the problem, by making them so. Keep up the good work. If that link above doesn't furnish a Service manual, it is imperative you get one, even if you must pay for it. It will pay for itself in about 2 mins. Now just replacing boards will most likely just end up with more faulty, boards, as related you MUST ensure that you have the cause of the event, before we change anything. I have seen so called, "Techs" replace every board, and virtually every component, and that STILL didn't fix it, because the "Fault, or Cause" lay elsewhere, and had not be repaired FIRST, you see that FIRST STEP, like everything in life, is, CRITICAL.

Hi, well I applaud you for wanting to have a go and try to repair you set. But PLEASE, start in the right place, otherwise you will simply waste your time and money, You see, you MUST start, in the right place, The power supply, FIRST, as, if, that isn't right, nothing else can be. But you simply cannot do anything without a Service Manual. In this it has everything one needs to repair the set. OK if it is shutting down, after that amount of time, of working and then faulting, then it is most definitely a "Thermal" problem, the way we "Find" problems such as this is "Freeze Spray" you use this on each component that is suspected of being the "Culprit" and you will soon,find that errant component. Now, also not every fault is a Capacitor, I see many, many people that think, that Capacitors are always the "Culprit" and replace them, because someone else had done so and it worked, well that maybe sometimes true, but most Symptoms, can, and do have many, many different "Causes" & also, now while that may be true in a few cases, a faulty Electrolytic Cap, or even, ordinary, Cap goes faulty, this is only a SYMPTOM, something has damaged those caps causing them to "Fail". One MUST always find the root "Cause", otherwise if you just treat, the SYMPTOM, the "Cause" will just make the "Symptom" come back, in short order, as the prime cause still, hasn't been fixed., Now Capacitors hate AC ripple, or Over Voltage. Thats it. Oh.. and Heat, if these Capacitors, are too close to a Heat Source, then thats a prime cause of failure. Resistors, hardly ever go faulty,and if they do, it is generally obvious. However it doesn't hurt to check values with our Multimeter. Remember though resistors are made, with up to 20% tolerance from stated value, as such, are not too critical, unless in Timing circuits etc. Always check, the Values, of resistors, as with any other component, with the power OFF. Now Diodes especially "Zener Diode", are another thing to check, those and ordinary "Signal Diode" should always be suspect. next we have Transistors and IC's. The Transistors MUST ALL be checked to see if they have a good, "Junction" this is done, with our meter set to "Diode Test" and usually are about 0.6 to 0.7. With IC's you must check, voltage levels, or Logic Levels, going in and out, have a look at the circuit diagram, and it will tell you what they should be. It is a good idea to always measure the Power Supply voltages, see if a "Rail" is Low, that will be because some component has gone somewhat or all short circuit, to Earth, now, if the "Rail" is Higher, suspect an "Open Circuit" component, like a Diode, or Transistor. The voltages expressed in the manual are spot on, ANY variation MUST be investigated. I have been doing all this for over 30 years now, and I do indeed wish, we could have a set of "Symptoms" and be ables to say.. "Oh that;s the so-in-so and replace this" however unfortunately this although does happen, most "Symptoms" can have literally tens, of "Causes" all often "Interlinked" One simply has to do a methodical troubleshooting procedure, and always think, "are my Voltages Correct" as this is how, you Fix the problem, by making them so. Keep up the good work. If that link above doesn't furnish a Service manual, it is imperative you get one, even if you must pay for it. It will pay for itself in about 2 mins.


Posted on Jul 13, 2010

  • hitech_repai Jul 19, 2010

    I have replaced the two IC's on the convergence circuit and there is no difference, when I checked the board on the two IC's they were hot. Can you tell me if there is something else I need to check on besides the power board? or is there any way I can get a service manual for this model to track the problem down? any help is gonig to be really appreciated. Thank you

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2 Answers

I have a JVC AV-56Wp74 Blue power light on the front keeps blinking and the screen is black & makes a popping sound


There are a couple of common problems this model has--one is easy to confirm.


How handy are you if I tell you to disconnect the convergence board to see if it is your problem?

The blinking blue light means the set is in protective shutdown, and I know a fairly easy way to see if it is your problem and how to fix the set if it is.

Let me know if you need help--I am here to help people and l know a lot about this set.

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It's recommended to replace all the defective parts first because if you only replace the defective resistor, it might burnt again if the convergence IC is shorted internally. I would also suggest to measure the other low value resistors with multimeter.

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Hello,

Did you lock the adjustment into the TV's memory? This step is the most often missed. Please follow the directions on the Users manual or on the service manual on how to set your memory to hold the configuration.

Find the menu item on setting the convergence adjustment into memory (the menu should have an informational screen on this topic)

I hope this helps

Thank you,

Shuttle83

http://www.electron-age-technologies-llc.com

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Hi, convergence amps have failed, your going to need a tech for that repair, involves un--soldering and re-installing parts as well as an alignment, hope this helps, video-tek

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sounds like a solder related issue on the convergence ICs. They are acessed through the front of the TV behind the speaker grille and then remove the small acess panel and you will see the convergence amp board with the two ICs on it.

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That 's actually a very reasonable price for a convergence board replacement in that TV. You can expect elsewhere to be double that or more. Unless you know electronics in TVs I don't advise trying to repair it yourself.

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1 Answer

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This link works for me; http://www.vancebaldwin.com/ hope this helps :) PS your search/security settings must need tweaking if you didn't get that link from google.

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