Question about JVC AV-56WP74 56" Rear Projection HDTV-Ready Television

5 Answers

Repeatedly blowing R842

I have replaced the amplifier IC's and the one resistor (R842 - 1.8 ohm) that was open. When I hooked everything back up, the picture was fine for about 10 seconds and the same resistor blew again and the picture was back to being bowed in at the top and bottom in the green. I replaced the resistor again and the same thing happened. Where should I check further for the source of the problem. Obviously, something is wrong elsewhere to keep blowing the same resistor. Any help will be greatly appreciated. If you want to email me, I am charles dot vance at westknox dot net. Thank you for your time and expertise.

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  • CVance Jul 30, 2008

    I checked the capacitors on the convergence board and cannot find any that look like they may be leaking or swelled up or anything else out of the ordinary. I was mistaken in the resistor number, it is R862. In tracing the lines on the circuit board, it appears to go from the amplifier IC to the green output plug.



    Thanks,

    Charles Vance

  • CVance Jul 30, 2008

    I checked the capacitors on the convergence board and cannot find any that look like they may be leaking or swelled up or anything else out of the ordinary. I was mistaken in the resistor number, it is R862. In tracing the lines on the circuit board, it appears to go from the amplifier IC to the green output plug.

    Thanks,
    Charles Vance

  • CVance Jul 30, 2008

    I will order a manual. Meanwhile, any other ideas I can check into?

  • CVance Jul 30, 2008

    Is the amplifier itself the large square metal plug in box on the convergence board?

  • CVance Jul 30, 2008

    I have a service manual on order.
    Is the amplifier the standup silver enclosed "module" that is not soldered onto the board but plugs in as a computer card would? If so, is this serviceable, as in checking resistors, etc?
    Also, since the resistor that is in question appears to go to the small cable for the green projector, could there be something in the green projector that is causing this?
    I am going crosseyed watching the messed up picture, so I am desperate to get this tv fixed.

  • CVance Jul 30, 2008

    The resistor I replaced the bad one with was a 2 watt resistor, the original was a 1 watt.

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5 Answers

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  • Master
  • 1,011 Answers

Dear,
is the resistance value is ok. if its exatly the same then check the wattage of the resistance. may be you are using the low wattagel resistance. resistance blows only if the heavy current (more than it rating) flow through it. check by using a high wattage resistor of the same value.

regards,

Posted on Jul 30, 2008

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  • Master
  • 2,296 Answers

I can send you the service manual.
Double check the solder as well and make sure they are not shorting out.
I would suggest to desolder pin # 7 and 9 from IC804. Also try to remove the wire that is connecting to the green convergence yoke.

Posted on Jul 30, 2008

  • Jaime Hernandez Jul 30, 2008

    Do not touch that silver square box, the failure is not there.

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  • Master
  • 3,037 Answers

Quit replacing the resistors, this can make it worse. What ever the fuse relays to must be replaced. Seems like it is the Amplifier since you replaced the ICs for it. Let me know if you have any further questions and good luck

Posted on Jul 30, 2008

  • Benjamin Patri
    Benjamin Patri Jul 31, 2008

    I just reread your first post, Is the green the only one out of
    alignment? If so then the amplifier is not the problem. ICs that
    generally are at fault are on the digital convergence board but since
    you replaced them, then I would actually turn to the green projector
    like you said and try replacing that. There must be a short in it or in
    the cable going to it.

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  • Master
  • 2,035 Answers

This could the problem with short in the board you need have service manual to verify the problem you get one from this website:


http://servicemanuals.vstore.ca/


Good luck....

Posted on Jul 30, 2008

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  • Master
  • 2,071 Answers

It is the capacitor caused that's the resistors blows,because the the capacitor cannot hold the storage voltage that why he passed it to resistor then the resistor can't also that why it's blow.Look for the capacitor associated to that resistor trace the line,for dryed up and leak capacitor...

Hope this may help;

Regards,
VOTIT

Posted on Jul 30, 2008

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