Toshiba 37AV502R

[Caleb]

I picked up this set today, presented with green led lit in front and blinking when trying to power up with no other signs of life. After a visual inspection showed no obvious signs of failure a quick test showed the power supply wasn't coming up. Jumpering ps on with a resistor allows everything to work properly. After a bit more testing Ive come to the AC detect circuit, according to the troubleshooting guide Im supposed to have .07 volts out of the power supply, mine is at .049 volts. I traced it back through the circuit and have a 103 (10k) resistor with 5v on one side and .049 on the other, it reads correctly at 10k, I was wondering if you all thought it ok to lower the resistor value slightly to bump the voltage, or should I still be going upstream to see if my 5v is supposed to be 7 or so? the resistor in question is R907 located in the upper left of the board in the picture.

[tw2005]

Re: Toshiba 37AV502R

Not that i know anything about these but in a 32AV500 manual it asks if it's below 0.07V.

No- Suspect a problem with
the power supply module

Yes - Suspect a problem
with the SYSCON
circuit located on the
Main module.

[budm]

Re: Toshiba 37AV502R

Do you have the schematic that you can up load?

[RON_CET]

Re: Toshiba 37AV502R

This might help some see attached,I'll try dig up schematic when get back to office Monday and I'll post that

[Caleb]

Re: Toshiba 37AV502R

No I was unable to find a schematic, I have the same guide tw2005 is using and ron posted above- however apparently read it wrong as I thought it said looking for more than .07v, So back to the main board I guess. Thanks for pointing that out Tw2005. It is those little details that bite you in the butt.

[Caleb]

Re: Toshiba 37AV502R

Go figure I put it back together and its decided to work without the jumper. Guess I will have set it up on the test stand and let it run for a few days.

[tw2005]

Re: Toshiba 37AV502R

Well, that's one way to fix it. Hope it holds.

[Caleb]

Re: Toshiba 37AV502R

Me too, but I kinda doubt it, when things fix themselves they often unfix themselves just as quickly. Its just going to wait until I get it all back together before it quits again.

[RobertW]

Re: Toshiba 37AV502R

Did anyone fix this fault? I replaced the small cap on the power supply. At first it didn't fix the fault but then did latch onto a start up. That lasted a few weeks but the fault has now returned. Perhaps a replacement with a different value but I don't know if I should go up or down from 22 mF

BOB

[Caleb]

Re: Toshiba 37AV502R

I used that one in the living room for two months then gave it to my dad. Its been working fine ever since. Thinking maybe a loose connection in one of the harnesses caused mine to fail. budm had isolated a similar problem on a 32" Toshiba to a leaky smd diode on the rear of the power board so you may want to look those over with your meter.