M550SV Vizio main board repair

[kerbsjacob]

I have a m550sv Vizio that is completely dead. No indicator led. Power supply tests good. Very confident main board has issues. Ldo regulators seem ok. No response to any buttons. Power supply is activated when TV is plugged in.
Ie , ps on = high and v out is good.

Anyone have experience or suggestions on this main board?
Crystal Oscillators are operational, however tcon PSU section is not powered on due to MOSFET being switched off.

Anyone have any suggestions?

[tom66]

Re: M550SV Vizio main board repair

These boards -- usually corrupt firmware flash chip. The chip is sometimes available for around $20 on the 'net.

[infringer]

Re: M550SV Vizio main board repair

Where is this firmware flash chip on the "net" ?

[Agent24]

Re: M550SV Vizio main board repair

You need to search the board model number in Google along with EEPROM and hope you get a result.

The model number is on the white sticker with the barcode (assuming you have the same board as the OP).

[vinceroger69]

Re: M550SV Vizio main board repair

ive been having a good look for the eeprom/spi flash for this set but can find anyone selling it so may have to look for a working mainboard for your set if available im not sure if you can then copy the contents of a working mainboard eeprom/flash ic over to your non working set as not sure what ic programmer is needed as i think this is a smart tv and may have some copyright on the ic etc from what i have read on various threads.

[infringer]

Re: M550SV Vizio main board repair

Set sucks I'd sell it for 200 bux at this point and take a huge loss I've replaced the main board 3 times and the power board once as well.

That is all I see with this set no TCON just a main board and a power board very odd I would bet that the good sets were the ones with the TCON and the LED greed driver board and yellow power board because this one won't run if you 3D printed robotic legs on it it boots up I mess with it for a few minutes or so then bingo no picture no sound and the status lights stays lit white. I am starting to wonder if something is causing a short like a harness or something screwy.

Something does not add up here either I am getting sold a lot of defective equipment or it is another part on the TV even replaced the breakout wifi card today to see if that was the problem.

Have you seen any bad screens cause this type of issue the picture is beautiful when it runs no issues at all. I don't understand what could possibly be causing this surely after 3 main boards and 2 power boards this thing should have worked.

What would cause this ?

[infringer]

Re: M550SV Vizio main board repair

Set sucks I'd sell it for 200 bux at this point and take a huge loss I've replaced the main board 3 times and the power board once as well.

That is all I see with this set no TCON just a main board and a power board very odd I would bet that the good sets were the ones with the TCON and the LED greed driver board and yellow power board because this one won't run if you 3D printed robotic legs on it it boots up I mess with it for a few minutes or so then bingo no picture no sound and the status lights stays lit white. I am starting to wonder if something is causing a short like a harness or something screwy.

Something does not add up here either I am getting sold a lot of defective equipment or it is another part on the TV even replaced the breakout wifi card today to see if that was the problem.

Have you seen any bad screens cause this type of issue the picture is beautiful when it runs no issues at all. I don't understand what could possibly be causing this surely after 3 main boards and 2 power boards this thing should have worked.

What would cause this ?

Some things to note about these sets:

IR board dying is common.
Shutting off after powering up is not like a typical easy problem to solve by replacing the main board.

Something is faulty with this unit that I have no doubt but what it is is really becoming a BIG question. Would love to really figure this out.

[Agent24]

Re: M550SV Vizio main board repair

Maybe the panel has an intermittent fault? Anything is possible I suppose.

Seems odd that 3 mainboards don't fix the problem. Unless it's the power supply and you just got unlucky with two bad ones.

[infringer]

Re: M550SV Vizio main board repair

yes oddly today I can not turn the TV on after unplugging it and plugging it back in very well could be I just find it interesting two bad power boards that exhibit the same conditions I am starting to wonder if it is a cabling issue.

It did happen after plugging and unplugging the main power harness that runs to the video board maybe I should order another one of these if I knew the pins required I'd likely buy those instead but for now hrmmm I wonder it almost looks like dupont spacing maybe I can make my own harness and try...

I will keep everyone updated on this one I've seen harnesses cause a lot of problems over the years working in the arcade industry for 13 years. So much so any time I make a harness it takes me a while because I am never sure of my crimps etc I check them several times over. Once in a while a pin crimp might wind up crimped a bit too tight resulting in cutting or busting the wire. But for now off to test count pins see what I can do etc

DOH! cannot make harness... but by all rights fiddling with it as long as I did should have allowed it to seat and turn on again no luck I think the power board is the culprit at this point wow! I got shafted on a power board from buyqual time to look elsewhere.