Vizio Vo47L FHDTV30A dead randomly

[ej207]

hello im trying to trouble shoot a Vizio Model# VO47L FHDTV30A

I tested all the pins in the plugs to the bottom right of the board and no voltage?. Weird i thought, so I made sure my multimeter was O.K. by testing other devices, even the wall outlet haha. No voltage at any pins.



Quick history on the board, previous owner which is an old friend of mine replaced two resistors not sure when or if they were even right can't find schematics on psu for this model googled for a while.
R901
R601

I'm not sure when was repaired to the time it broke on me, probably a few months? I was watching the TV and it shut off. No power led's nothing its completely dead. I have fixed some TV's in the past that just had the obvious blown caps, I don't see any bulging caps. Here is some pics of the boards i'm looking for some advice on troubleshooting to find the bad component to try fixing it and if worse comes to worse i'll just replace it but I would love to avoid ebay if anyone has some site recommendations.

[ej207]

Re: Vizio Vo47L FHDTV30A dead randomly

pic post

[triplefour]

Re: Vizio Vo47L FHDTV30A dead randomly

checked fuse? volts at main filter cap? (careful thats the deadly one)

[ej207]

Re: Vizio Vo47L FHDTV30A dead randomly

I've checked all fuses and i'll try that, what voltages am I looking for?

[triplefour]

Re: Vizio Vo47L FHDTV30A dead randomly

on the main filter cap you should see 160-170v
keep the black probe on the negative leg of the main filter cap, and probe the diodes in the area next to it to see where you lose voltage?
i havent had a lot of success yet with repairing PSU's at component level. i still need a lot of help from the masters here
but just be cafeful with that main filter cap thats all i can say cuz it hurts!

[ej207]

Re: Vizio Vo47L FHDTV30A dead randomly

Nice, I will try that. I don't know what the main filter cap is though.. i will google some pics and see if i can't figure that out thanks

[triplefour]

Re: Vizio Vo47L FHDTV30A dead randomly

its the biggest capacitor on the board. in your case, the one that is surrounded by the heat sink but not under it

[ej207]

Re: Vizio Vo47L FHDTV30A dead randomly

in CAP mode on multimeter, readings were erratic but only when recontacting multimeter probes. im no pro, not sure if that is even an appropriate setting.

as this picture illustrates, that huge cap was reading 160 volts. im not sure how to test those resistors maybe my multimeter sucks but on both leads it was still 160 volts

[triplefour]

Re: Vizio Vo47L FHDTV30A dead randomly

not sure about the CAP setting on your multimeter. mine doesnt have one. just setting your meter to 200v DC range should be good enough.

[ej207]

Re: Vizio Vo47L FHDTV30A dead randomly

Yep, that was my result. Appreciate you taking the time to help e-troubleshoot.

idk what voltage should be at the cap, i don't have any schematics for this PSU. do you? I have googled !

[budm]

Re: Vizio Vo47L FHDTV30A dead randomly

Voltage on the main cap should be 160~170VDC in standby mode, > 350VDC when TV is on.
I need good clear pictures of the bottom side of this power supply-inverter board combo, the whole board picture and in closed up in quarter section so I can easily trace the connections on the bottom side of the board.
BTW, you do not have any DC Voltage at the 5VSB pins at all?