50" Vizio blank screen

[crankn101]

Well im a total noob at TV repair, but after fixing one I thought it wasnt too difficult so I tried another...

I bought this TV not working so...vp50 HDTV20A

First I took off the back panel and saw a bulged capacitor on the power board and also one on the X-main board. So I replaced them hoping that was all, WRONG. It changed nothing that I can see.

So when plugged in the orange standby light is working then when I turn on the power the green light on the front turns on like normal. In the back their is a green flashing light, im not sure if thats normal and sometimes during power up I can see some white fuziness across the tv.

I will post pics and board numbers in my next post. It might take a while.

Any info would be greatly appreciated.

Thanks Dustin

[cashkennedy]

Re: 50" Vizio blank screen

Did you test all the ouput voltages from the power supply to make sure they were correct? Thats usually an easy place to start.

[crankn101]

Re: 50" Vizio blank screen

Did you test all the ouput voltages from the power supply to make sure they were correct? Thats usually an easy place to start.

I tried, but I couldnt find out what the voltages were supposed to be. Ill have to look again.

Thanks

[crankn101]

Re: 50" Vizio blank screen

Power board- pspf561A01A

X-main-LJ41-05171A

Y-main-Lj41-04217A

W2 Logic main-LJ41-04220A

[cashkennedy]

Re: 50" Vizio blank screen

The rainbow / multi color wires running from the bottom of the power supply have writing next to them, i cant make out all the writing but i see gnd next to some, and the others should have voltages.

If the thicker grey / black wires have markings on the board next to them that indicate voltages bellow 240 then you should be able to safely test those voltages to see if you are getting the voltage marked on the board.

Ive never worked with plasmas so i honestly dont even know what those thicker wires go to, but i think they are usually much higher voltages. You should make sure your using the right range on your multimeter for the max voltage and testing while the tv is turned on, and test either the voltage pin to the ground pin, or the voltage pin to a peice of grounded metal on the case. Usually either will work when your testing voltages exiting the power supply.

[crankn101]

Re: 50" Vizio blank screen

I tested the black and gray wires to the X and Y boards both were right at 1.8 volts.

Im thinkin I did tested it wrong. Ill go check again.

[crankn101]

Re: 50" Vizio blank screen

The first time I tested the X and Y boards I just had the TV plugged in, this time I actually turned the TV power on and both read at 4.0 volts. The X board reads...VCC 5 and I cant find a number on the Y board.

[crankn101]

Re: 50" Vizio blank screen

Well I tried again...Do these numbers seem right? Does it appear im testing them correctly?



X-Main
VG=15.04 Volts
VCC=209 Volts
Vcc=209 Volts

Y-Main

VS=15.04 Volts
VCC=209 Volts
VCC=209 Volts

W2 Logic Main

D5V=5.13 Volts
Va=63.1 Volts

[crankn101]

Re: 50" Vizio blank screen

This light is not powering up. Could this be a clue?

Any help would be great. I know it has to get old helping the helpless...

[cashkennedy]

Re: 50" Vizio blank screen

Theres already 8 threads on this model on this site, with 3 of them explainign how to fix the exact problem you have. Have you even tried to read through all of those?

1 of them clearly mentions that the 207 volt line, 63 volt line are labeled on the power supply board. So it looks like your problem is not with those voltages, but i didnt read through all 8 of the other threads on this model, so youll have to check them out for yourself.

Im confused though why your readings were like 4volts, now your getting 200 like you're supposed to get, and it seems like your not trying things totaly blindly as you know all the boards names and stuff. So maybe youve read some stuff on this model recently?

[crankn101]

Re: 50" Vizio blank screen

Thank you sir. Ill do a better search.

Im just slowly learning from this site and others, I use any tips from members and try to educate myself from there.

I think the first time I tried a voltage reading It was on stand-by power instead of powered on. Then the 2nd time I had my MM on AC...I know...D-U-M-B!

[crankn101]

Re: 50" Vizio blank screen

Alright your suggestion to search this forum helped out lots. I thought I already did but apparently not.

So I might have narrowed it down to my upper buffer board, but I dont know how to rule out the Y-board. This is what im getting now. When I remove the upper buffer board the bottom half of the screen lights up. But I still cant seem to get an image on it.

Any other suggestions?

And on my buffer board it looks like some solder got hot and shorted out a couple of the buffers scans. One even has pin holes through the top like it got hot.

Here are some pics.

[crankn101]

Re: 50" Vizio blank screen

Someone want to push me in the right direction?

[cashkennedy]

Re: 50" Vizio blank screen

Unfortunately I have 0 experience with plasmas, so am not able to help you much.

I have read a few plasma threads and usually if it lights up when 1 buffer is removed you know the buffer that is removed is bad? Or is it vice versa i forget. But I think you have made the proper test and hopefully someone will be able to tell you , who knows more about plasmas.