Vizio e420vl possible power supply issue?

[FoZzIzoz]

Hello ya'll!
This being my first thread i guess i will start my existance off on badcaps with a puzzle.
I picked up this e420vl a while ago for rather little money.
The previous owner complained that after lightning had struck a transformer his house is tied into, the power died and after it returned he found all HDMI inputs on this tv were no longer working (OSD says no signal).
So i got the set home and started to play with it. I found that all other video inputs work perfectly (VGA, RCA, onboard tuner) BUT without audio. I later found that the tv is processing audio, but can only be heard through an external unit via the audio out rca jacks.
So i discussed this with a good friend who rather savvy when it comes to anything related to silicon and he seems to think the likely cause is either shorted/faulty component(s) on the mainboard, possibly HDMI switching ICs and/or audio amp IC.
Because i lack the soldering skills and steady hand to fool with surface mount components and the proper test equipment/service manual I started to shop around for replacement mainboards. found a seller on ebay for a used but working exact match, listed at $60 vs near $100 every other listing advertised. seller had excellent feedback so i figured why not.
Well i received the board tuesday, installed and it appears that it wont power up. the only sign of life is the red LED backlight behind the vizio logo on the front that indicates standby i think.
the board gets voltage.. all of the voltage regulators on the board are outputting power as if the board is on. so i notified the seller and let him know i am rather sure my psu is good, told him you must have sent me a defective board. he offered to send another board but the closest match he had was with newer firmware.
That board arrived today.. but appears to be even worse off than the first he sent. Theres no standby led, I see no voltage on the power switch.. nothing, I still have all 3 boards and am rather clueless on what to do now.
very sorry about the long-winded post.

http://i.imgur.com/jJDIklN.jpg
I figured id toss in this picture despite the mediocre quality. if a more clear pictue is needed i will need to borrow a camera, so let me know!

ID#: 0171-2272-3253

Also i have checked for appropriate voltages on all power rails and everything appears to be in good order.

Thanks alot yall, hope ive included enough information to give yall an idea what ive got on my hands here.

[tom66]

Re: Vizio e420vl possible power supply issue?

It's more than possible both your replacement main boards are bad.

Vizio main boards are among the least reliable in the world. And most parts you see on eBay are untested, despite what they say. They are pulled from TVs that have been smashed. My theory is many people get annoyed when their TV breaks down, hit the screen in an attempt to get it working... and that's how it ends up on the curb.

[FoZzIzoz]

Re: Vizio e420vl possible power supply issue?

Thanks for the swift reply mr. tom!
I kind of figured but was hoping it might be otherwise.. Time to try this sellers return policy.
That seems very likely, at least for most cases.. I'd imagine a good seller of parts who "tests" their units before listing would at least try to see if the set attempts to power on.
then again maybe i expect too much.
Well Instead of play mainboard roulette again, how possible do you think it will be to isolate the audio issues with just a meter? id be willing to take a crack at soldering a new IC or something as long as the pin count is not too high.

Thank you mr. tom!