26AV500U Toshiba LCD TV power supply issue?

Discussion in 'General Electronics Chat' started by jchin92, Oct 9, 2011.

  1. jchin92

    Thread Starter New Member

    Oct 9, 2011
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    i was repairing a 26AV500U Toshiba and it had no picture but sound, shined a flash light and saw a picture. so i thought i was the inverter, so i replaced it and it worked for like 2-3 days then went out. so im asking if its a power supply issue before i get it replaced and if my inverter is goood or not.
     
  2. tom66

    Senior Member

    May 9, 2009
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    You probably got a dud inverter, it happens.
     
  3. jchin92

    Thread Starter New Member

    Oct 9, 2011
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    so i should get another inverter?
     
  4. tom66

    Senior Member

    May 9, 2009
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    I would send it back as faulty and buy a new one. Inverters can die after a few days of use.
     
  5. jchin92

    Thread Starter New Member

    Oct 9, 2011
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    What if the new one goes bad? Has it been crossed out that it isn't a power supply issue
     
  6. tom66

    Senior Member

    May 9, 2009
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    Have you checked the power supply voltages to the inverter? It is usually 24V.
     
  7. jchin92

    Thread Starter New Member

    Oct 9, 2011
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    How do I check that?
     
  8. jchin92

    Thread Starter New Member

    Oct 9, 2011
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    so i just openned to tv and disconnete the inverter and reconnected and it worked so im guessing the power supply is failing
     
  9. tom66

    Senior Member

    May 9, 2009
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    It's possible. To check the inverter power supply you will need a multimeter, do you have one?
     
  10. Jotto

    Member

    Apr 1, 2011
    159
    17
    I doubt your P/S is bad. Inverters are a major problem in LCD units.

    Inverter could run off 12, 24 or 48VDC, some use more then one. You will have a switched voltage for turning on the inverter and also the main power for the inverter.

    The inverter can be powered up without the unit being totally hooked up. I run the inverters without the A/D board. I use two power supplies, but you can use one if you like. If you know what your main power is you can jump off of that but will have to use a resistor for the switched voltage. The value of the resistor is anywhere from 4.7k to 47k.

    I would suspect the inverter or lamps. The unit will most likely be using a royer oscillator to make sure the load is balanced.
     
    Last edited: Oct 12, 2011
  11. jchin92

    Thread Starter New Member

    Oct 9, 2011
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    I just bought a power supply because the TV shop told me it was that. I do have a multi meter.

    @jotto that seems really complicated
     
  12. dataman19

    Member

    Dec 26, 2009
    136
    29
    The filter caps on the Inverter prime power feed are most likely your culprits.
    ..
    This is a common problem with these TVs...
    Check the filter caps on the main power supply board. Look for distorted caps (domed caps), leaking caps or discolored caps. Specifically look at the ones that are feeding the Inverter board (just follow the power lead from the inverter back to the Power Supply Board).
    ..
    Dave
    dataman19
     
  13. tom66

    Senior Member

    May 9, 2009
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    It would be easy to test the power supply outputs. Could you take a picture of the power supply and post it here?
     
  14. jchin92

    Thread Starter New Member

    Oct 9, 2011
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    i have tried two perfectly working units the PSU and the inverter. itll stay on for a few minutes like 10 minute then go off. leave the tv off for a few minutes, and i turn it back on it ll work.

    my old inverter had leaked caps and everything. my new one is in good order.

    http://www.interliquidparts.com/wp-...ct_images/POWER_SUPPLY_UNIT_PK101V0540I-2.JPG

    heres and image of the psu. not mine though. i already swapped power supplys. it was a no go same problem. i've posted this up in other forums and was told maybe my bulbs are just going bad.
     
    Last edited: Oct 15, 2011
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