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JVC AV-27790

Discussion in 'Electronic Repair' started by J.B. Wood, Jun 25, 2007.

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  1. J.B. Wood

    J.B. Wood Guest

    Hello, all. After 11 years of trouble-free operation of the subject TV
    the following has occurred within the last two weeks:

    The set would periodically lose vertical sweep (single bright horizontal
    line). Vertical sweep would often be absent upon power-up. Lightly
    bumping the cabinet would often restore the sweep for the rest of the
    evening's viewing but return the next day.

    The set finally quit altogether with the power cycling endlessly on then
    off until the line cord was unplugged. There was a very pronounced burn
    smell emanating from inside the cabinet.

    I removed the back of cabinet and as best my olfactory sense could
    determine the burn smell is coming from what appears to be the RF
    enclosure of one of the tuners (the set has two). There does not appear
    to be any evidence of burned components elsewhere on any of the three
    circuit boards.

    Why the tuner would have anything to do with vertical sweep failure is
    confounding. The suspect RF enclosure/assembly is located at the top of
    the following vertically-mounted circuit board, which is marked (on its
    underside) as follows:

    At top left of board - JVC PWS 96.5.20 SOMEYA

    At bottom of board - CKF0426-AS1-1 CMK-81X

    Any help in facilitating repair would be greatly appreciated. Thanks so
    much for your time and comment. Sincerely,
     
  2. Guest

    J.B.Wood:
    If you would have had this fixed before it quit altogether a shop
    probably could have done the repair for about $40 to $60 or so....
    resoldering connections near and around the vertical deflection output
    circuitry and flyback derived B+ supply and may replacing some high
    ESR electrolytics.... now that the television has quit altogether
    and there is a burnt smell the repair and parts price will be much
    higher and extent of the repair will be much more involved.
    television to start with it sounds to me like you are way over you
    head on this one. My advice is that you take it to a repair shop for
    at the very least a repair cost estimate so you can make an
    intelligent repair deciesion with real numbers from a real tech who
    opened the set and make tests and measurements.
    If you want to further investigate a DIY repair you should go to the
    website for this newsgroup at
    http://www.repairfaq.org/
    There, with some search time, you will find a wealth of
    troubleshooting, testing, repair and IMPORTANT SAFETY information
    regarding television repair proceedures.
    Best Regards,
    electricitym
     
  3. J. B. Wood

    J. B. Wood Guest

    Thanks for the response! You make some excellent points but I doubt a TV
    repair shop these days spends a lot of time troubleshooting and soldering
    at the board component level. There's just too many surface-mounted
    components to deal with. I suspect if the shop can trace the problem to a
    board assembly it becomes a swap out issue. Then there's the issue of
    whether that board is available for an 11 yr old set. If that faulty card
    cannot be replaced then the shop would probably say the set's not
    repairable (or alternatively put, "you wouldn't want to spend what it
    would take to put the set into working order").

    I was hoping to get some insight into what board(s) might be at fault in
    my set and then attempt a swap out. Sincerely,

    John Wood (Code 5550) e-mail:
    Naval Research Laboratory
    4555 Overlook Avenue, SW
    Washington, DC 20375-5337
     
  4. Guest

     
  5. This set is rarely, if ever, repaired by replacing a board. The repair
    should be very straightforward for most TV techs. Your assumptions are
    faulty. You could spend several hundred dollars to buy the board, if it is
    available. The repair should not be much more than $100 at the component
    level. As you were told, you might have made it much worse by not dealing
    with the very common intermittent solder connections until the more severe
    failure occured. Get it to an experienced shop.

    Leonard
     
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