VIZIO L42HDTV10A No power coming out of PS board

[jrem]

Hello,

My Vizio set completely stopped working a couple days ago after we heard a loud pop while watching TV. Plugged into the wall I can't get anything to light up. Took off the back and checked the power supply board:

120VAC on both sides of the fuse near the main power coming in w/respect to blue wire
165VDC across the largest cap
0VDC on all pins of CN5(main board connector) w/respect to SGND pins on CN5
0VDC on PSON pin (pressed or unpressed) w/respect to SGND

None of the caps look like they're bulging/exploded/leaking. The only suspect thing I can see on the board is IC601 (on the bottom) looks like its been gouged out in the middle of the chip.

Any suggestions on how to proceed with troubleshooting?

Just wanted to say I wouldn't have gotten this far without looking at other threads on this forum, I think its awesome that this kind of community exists!

[Mr Bill]

Re: VIZIO L42HDTV10A No power coming out of PS board

IC601 shorted out and burned a hole through it. Can you make out the numbers on it? Depending on locating that IC and your soldering skills you might be walking that fine line where a replacement PSU is your only option.

[budm]

Re: VIZIO L42HDTV10A No power coming out of PS board

That is the SMP IC for the 12v/24v power supply section, more likely to have two blown MOSFET's and blown Gate drive component also. I would say look to see what the replacement will be first.
Not sure which version you have: http://www.shopjimmy.com/catalogsear...ZIO+L42HDTV10A

[jrem]

Re: VIZIO L42HDTV10A No power coming out of PS board

Kinda tough to make out the IC numbers but I can see "DEI 84 9XXX626" with a "01D" above it, the XXX part represents the blown hole...

I'm confident I could replace it if I had the correct part in front of me but it's looking like it might be easier to just replace the whole board? Any idea how much the IC and/or MOSFETs and gate drive would all cost? The board is a DPS 2838 AP A, found it on a few sites but it's out of stock on a lot of sites.

I don't know much about MOSFETs and gate drives is there an easy way to test them? I'm also not sure where they are located... I'll use Google and see if I can spot them on the board.

Thanks for your help!

[Mr Bill]

Re: VIZIO L42HDTV10A No power coming out of PS board

I actually have a 0500-0507-0201 PSU DPS 283AP B from a GV42L. IC601 on mine is a DEI 91A1702

[budm]

Re: VIZIO L42HDTV10A No power coming out of PS board

OK, no matter what, you will have to remove the IC first, so try removing the IC and see if you can do it without damaging the board first, then we can remove the MOSFET's and related parts around to see what else is bad.

[jrem]

Re: VIZIO L42HDTV10A No power coming out of PS board

Ok, I got the IC removed but slightly damaged about half of the traces... so I ordered a used board off ebay for about $50.

Got the new board in the mail today and I made a huge mistake.... in my excitement to test it out and see the TV work again I set it inside of the TV case, plugged everything in, then plugged in the power cable. Got a quick spark from under the board and my heart sank. I hadn't screwed the board in place... very very very dumb move on my part.

One of the traces on the bottom was fried off the board so I replaced it with a piece of wire, IC 952 also got a spark and the chip appeard to be ok but I replaced it with the chip from my first board anyway to be safe. I double checked continuities on all my new solder joints and they were good.

After the spark I got no voltage on the large capacitor, after repairing the two components above I got 167 volts again across the capacitor but still nothing at all on the CN2 CN3 and CN5 pins

I don't see anything else visibly wrong but is there anything else I could maybe replace on the new board using parts from the old one? I'll just have to fork over another $50 for another board if I can't fix it. I guess lessons are learned the hard way sometimes...

[nukid]

Re: VIZIO L42HDTV10A No power coming out of PS board

wow...my board looks the same underneath that ic as yours (last post date 10/13/12), a "hole" out of the middle of it. Also, when I replaced the blown fuse it sparked again and blew a hole in the top of R623 and a nice trail burn mark on the board. My curiosity is...if I just replace the power board, and make sure it is screwed down FIRST, do you think that will solve the problem or may there be an issue on other boards that may have caused this issue in the first place?

[jrem]

Re: VIZIO L42HDTV10A No power coming out of PS board

Yeah thats basically what I'm hoping for... Not saying there couldn't be a problem with one of the other main boards but I think that's not very likely? All we know for sure is that at the least, the power supply board is not functional and needs to be fixed/replaced.

Though it would kinda stink if the power supply board was replaced/fully functional and the TV still didn't work... then you're potentially wasting money on a TV that might not be fixable.