Inverter problem?

Discussion in 'General Electronics Chat' started by burntfingers, Jul 20, 2011.

  1. burntfingers

    Thread Starter New Member

    Jul 20, 2011
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    Got this Sansui SV-2615 LCD cutting off the screen, sound remains OK.
    Needs switch off and on again to bring picture back [perfect picture].
    Takes longer to shut screen when it's cold, and less and less as it warms up.

    I checked the power board for d/js and used a computer fan to extract heat, to no avail.
     
  2. Kermit2

    AAC Fanatic!

    Feb 5, 2010
    3,779
    932
    Shotgun replace any electrolytic caps in the sweep drive circuit area/

    (I seem to have suggested this on several topics lately) :)
     
  3. burntfingers

    Thread Starter New Member

    Jul 20, 2011
    8
    0
    Thanks.

    The set is right now holding, since I installed a computer fan as shown in the picture supplied, blowing air into the components.
    There is a small cap I'm going to replace soon, but could it be the chip, instead?
     
  4. #12

    Expert

    Nov 30, 2010
    16,261
    6,768
    It could be anything. Based on no drawing and no measurements, it could be anything. With this much information, the best anyone can do is recommend you to the most likely parts, and they are capacitors.
     
  5. burntfingers

    Thread Starter New Member

    Jul 20, 2011
    8
    0
    So far, while blowing air on that IC, it is holding picture!
     
  6. burntfingers

    Thread Starter New Member

    Jul 20, 2011
    8
    0
    This inverter IC could be the culprit, after all.
    I haven't got one at the moment.
    Just sent an email to Mastercare Sparescare, here in Johannesburg to see if they stock it.
    I have told the customer that the set is holding nicely while the fan is going - a low noise one, by the way.
     
  7. SgtWookie

    Expert

    Jul 17, 2007
    22,182
    1,728
    IC's can fail after many heating/cooling cycles. The expansion and contraction flexes the bonding wires that connect the pins to the substrate; eventually they develop metal fatigue and fracture, like bending the tab on a soda can back and fourth a bunch of times. They can still be in contact when cool, and then break contact when they heat up.
     
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