26AV500U Toshiba LCD TV power supply issue?

Thread Starter

jchin92

Joined Oct 9, 2011
7
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.
 

Thread Starter

jchin92

Joined Oct 9, 2011
7
so i just openned to tv and disconnete the inverter and reconnected and it worked so im guessing the power supply is failing
 

Jotto

Joined Apr 1, 2011
151
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.
 
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Thread Starter

jchin92

Joined Oct 9, 2011
7
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
 

dataman19

Joined Dec 26, 2009
135
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
 

tom66

Joined May 9, 2009
2,595
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
It would be easy to test the power supply outputs. Could you take a picture of the power supply and post it here?
 

Thread Starter

jchin92

Joined Oct 9, 2011
7
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-content/uploads/wpsc/product_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.
 
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