Need help finding a voltage regulator

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2[H]4U
Joined
Jun 12, 2001
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The other day I found another LCD Flat Panel TV in the trash
The TV is a Vizio VL370M Of course it does not work but the screen is intact and in excellent condition, The frame is also in excellent condition.

When I plugged it in the Vizio symbol lights up Yellow and when I attempt to power on the TV the Vizio symbol will turn white and the screen will light up and then nothing (No Picture or sound or menus) The TV will stay on in that state until either unplugged or I press the power button again

I have removed the back of the set as I was told on another forum that the main board is bad. I am just double checking with this forum before I order the Main Board.

The numbers on the main board are:

Printed on a sticker
3637-0552-0150(5E)
0KM4049AQ14155E
CSD:3637-0552-0395

Written on the board in white text
0171-2271-2855

All of the boards I saw look the same but I take it I have to order this exact model of board with the same numbers on it for it to work correctly?

Thanks

That's what I posted on another forum but I am now wanting to replace the bad voltage regulators but I am having a tough time finding a replacement part

The bad voltage regulator is marked "L334
G1084"

I also have another regulator marked L7805T (That one is common enough though)
 
Pics of main board? Unfortunately, the long part numbers you listed won't do much good if you're looking to repair it. As for the regulator, I gotta ask: are you sure the regulator's the cause of the issue? The symptoms seems similar to those caused by bad caps. Of course, my experience comes entirely from fixing monitors, not TVs, but I've at least seen this behavior before.
 
Have you tried mouser yet?
http://www.mouser.com/

That said, Mohonri has a point about the caps. I'd check those out thoroughly before replacing the VR.

If any of the caps look bloated like this:
bad-caps.jpg

replace them.

Even then they could look normal and still be bad.
 
90+% of the time it's bad caps that cause the power supplies to fail. Sometimes the failing caps take other components with them, sometimes not. The L334 is probably a LM334 adjustable current regulator. If the caps are bad, replace with good caps of the same value, like Rubycon, Panasonic, or my personal favorite, Sanyo OSCON.
 
OK so I replaced the Main and the T-Con (Timing Controller) board but it turns out the power supply is bad (Missing the +12VDC voltage rail) is there a way to get this to work with a PC power supply (Temporally) just so I can see if the LCD panel is actually good?, The panel looks good but I want to make absolutely sure before I buy yet another board (The TV only has four boards being the PSU, Main Board, T-Con, and the IR Remote sensor board) So far I have replaced two of the four boards.

Power Supply
PSUconns.jpg


PSUburnt.jpg


The T-Con board also burnt up

T-Con.jpg


Chassiscover.jpg


Chassis.jpg
 
Well, rats--you posted two pictures of the power supply board, and (barely) missed the capacitors that we so often see dead. Any chance you could get a shot of the middle of the power supply board?

Yes, you can likely jimmy-rig a computer PSU to the pins on the board (hey, at least they're well-marked!). Just make sure you don't have the monitor's power cord plugged in when you do.
 
OK here is a picture of the complete power board

PSU.jpg


The weird part is the TV will turn on but no picture (Just the backlight comes on) as the PSU is missing the +12VDC rail
also the power supply unit PCB is the backlight inverter so with out that plugged in there will be no backlight
I guess I could try connecting a PC PSU to the +12/5VDC points and look at the screen with a bright flashlight
 
There's a very good chance the backlight runs off the same 12V rail as everything else. Give it a whirl--you shouldn't hurt anything by hooking up your computer PSU to the 12V, 5V, and GND rails on that board. Given that the backlight works, my guess is that the 5V rail isn't working, or there's a 5V-to-3.3V regulator on one of the other boards that's smoked.

EDIT2: Actually, that second possibility is more likely--I'll bet that large regulator *is* smoked on the other board. It matches up nicely with the nice smokey mark on the sheet metal. What's the part number on the big chip in the middle? If we can figure that out, we can likely figure out an appropriate replacement regulator. There's also the possibility of cascading failures--caps (or something else) on the power supply board fail, voltage goes all over the place and smokes the regulator...

Edit 3: Any chance we could get a closer photo of the brown capacitors near the 12V/5V output pins?
 
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