Vizio VP322 - no power, blown resistor and fuse

[sansonet]

Previously I successfully repaired the same plasma with usual capacitor problem, so I thought this one will be easy fix too. But when I replaced two 3300uf bulged caps, it came on normally at first, but after 1-2 min I heard some kind of blast inside and it went dead. Found blown fuse and resistor and replaced with what I could find at moment. Resistor is same color code / parameters, but little bigger in size. Fuse looks messy, but I think it should do for now.
After taking better look on caps, I figured out this TV already was repaired before and caps were replaced. Originals are Samwha WB series low ESR caps, but board was filled with some unknown brand caps, looks like general purpose ones. I'm attaching pics of some of them. I wonder if those caps damaged power supply board.
Where I should start to look to find failed component? Right now TV is completely dead, no standby light or anything, not even 5V power on connectors. Tested some resistors in the same area - everything else appears to be in working condition. Here is pic of the same board http://assets.shopjimmy.com/media/ca...9401-top_2.jpg

[momaka]

Re: Vizio VP322 - no power, blown resistor and fuse

...but board was filled with some unknown brand caps, looks like general purpose ones. I'm attaching pics of some of them. I wonder if those caps damaged power supply board.

That could very well be the reason. You never know if those cheap caps either came shorted or open straight from the factory. Or it could also be a bad repair job by whoever tried to fix this before you (i.e. caps installed backwards, wrong voltage or capacitance used, solder bridges or weak solder joints, etc.)

Where I should start to look to find failed component? Right now TV is completely dead, no standby light or anything, not even 5V power on connectors.

Looks like a power supply issue so start by posting clear top and bottom side pictures of the power supply board. And later when we find the problems, those cheap caps will need to go.

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

Polarity was right, also after that first repair TV worked for while until two 3300uf caps bulged - those two usually go bad first in this TV model, even with factory caps. I wonder if something could be damaged just because bad quality and wrong ESR caps was installed and TV was used with them for while.
I'll make pics later, but I don't really see anything else wrong with visual inspection, even when using magnifier.

[momaka]

Re: Vizio VP322 - no power, blown resistor and fuse

Well, now that a fuse blew and you have no output voltage, we will need to check the power supply. Shorted semiconductors don't always show visual damage when they go bad.

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

Sorry I was not able to get back to this board since I posted last time, but last week I bought another power board with 3 usual bulged caps so I dint pay too much ($22 vs $60+ for working boards), replaced caps and TV works now. Since I still curious about first board, I tried cross check it with working board. Tested components in close location to burn. One that reads different - is resistor 103 circled in red. It reads 10K as it should on good board, but just little over 1K on bad one. If removed, reads 10K as it should. I checked components that connected to it, all seems fine, also I desoldered everything that connected to it to see what will give correct readings. Removing R152/R153 from circuit brings resistor 103 to correct readings, but two those are good too. Tracked it to IC 151 chip - this one reads way too different from one on good board. Could this one be a problem? It marked 1207A, I think this one http://www.digikey.com/product-detai...SCT-ND/2121253

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

Also, now when it powers up, I noticed a small problem with image and not sure if this is how it should be in plazma. When image is dark/black, it gets some kind of grain delay/shadow on parts that switching from light image to black, it lasts only fraction of second, but still noticeable if I look close. Noticeable when, for example, TV plays titles at movie end with white letters moving on black background. They all having grainy shadows under them.This is pictures of how it looks for few milliseconds when blue HDMI square goes away. I adjusted lightness on second pic so it can be seen on picture.
If this not normal for plasma TV, how it can be fixed? I can buy main board for $15, but really hope I dont need invest any more in this TV. And I not sure if problem is with main board. Menu screen seems fine, but its is light colored so it hard to tell.

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

Not sure if anybody reads, but I just discovered that person who replaced caps before, used two 1000uf caps to replace 470uf caps. 470uf caps are on working board and they are original ones. Now I pretty sure this is what caused damage, but they are located in different area of board - near connector to mainboard.

[Shinju]

Re: Vizio VP322 - no power, blown resistor and fuse

The image being retained is not a mainboard issue, these have a all in one sustain board, your buffers,X and Y are all on one board.

I would check your VA/VS and other Sustain voltages before spending anymore money.

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

Thank you! I'm pretty much helpless when it comes to plasma - never repaired one, just power boards in this model. Checked voltage on connector which is on picture attached, not sure if this is correct one:
VS (both) - 194V
VA - 60V
5V - 5V

Second pic is T-Con (I think) and there is green led blinking when it's on. D103 have steady green led, and D201 blinks every second. Not sure what blinking means - normal operation or indicates a problem.

[Shinju]

Re: Vizio VP322 - no power, blown resistor and fuse

If you do a search I recently helped another member with this panel, there is a couple more Voltage reading we need.

But on the bight side the sustain board is super cheap for these.

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

OK, i'll check it out, I did search for this model before, but I was looking for power issues back then.

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

I fond this thread https://www.badcaps.net/forum/showthread.php?t=43338
I think this is the one you was referring to.
I checked test points as mentioned in that thread
VSC - -94.8
Vzb - 139.3
Since you said it should have VSC -185 - does it meant my YSYS is bad too?
Also, is there any way to fix it vs buy all board? I know they are cheap, but I payed $30 for TV (thought it will be easy with just cap replacement...), then for power board, now if I should buy one more board for it it will turn to one expensive repair....

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

I still not sure what to do - should I order another YSYS board, will it fix that grainy delay problem? Or problem might be with something else?
Here also pic of panel sticker

[Alastair E]

Re: Vizio VP322 - no power, blown resistor and fuse

Check all the low-value flame-proof (green bodied) resistors....

[Shinju]

Re: Vizio VP322 - no power, blown resistor and fuse

At the cheap price of the Sustain boards for these I would take the gamble. If you get it from shopjimmy and it doesn't solve your problem they will take it back if the board doesn't get damaged on install.

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

I'll check resistors. As for ordering and returning board - its $13 on shopjimmy and shipping is ~$10, they will not refund shipping if I just diagnosed wrong one, plus restocking and return shipping which I should pay myself - so I might end up loosing more money returning it then original amount I'll spend on it.

[Shinju]

Re: Vizio VP322 - no power, blown resistor and fuse

Or just keep it for extra parts, Keep plugging away at getting voltages!

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

I just received new IC 1207A that I ordered, I mentioned that IC in post #5 (actually, I ordered 1207B because they didnt had 1207A in stock), replaced it on original board that was dead, and of course, replaced wrong 1000uf caps with 470uf ones - fired TV and it came to life. I hope tit fixed it, I still need replace rest of caps and fuse with right ones, just not sure if I need replace resistor that blew with fuse (post #1), current replacement is same value, but bigger size/W. I tried to power on for just minute, hope it will work on long run too.

It is most expensive part in this model so selling it might cover my other expenses with that TV so it will be not so expensive repair and I will feel no to so bad about ordering YSYS for it too.

I still will check resistors on YSYS first. Do I need unsolder them or they should show correct readings on board?

I also wonder if wrongly done previous repair on this TV caused that malfunction on YSYS too? Or it is just separate problem?

[alfonsoreyesd]

toshiba 32SL410U

OK i have this tv, wont power voltages in conectors cn2 and cn3 psu are ok, i already replace the output caps just in case,,, what i found kind of weird is voltages on big fat transistors in logic board go up and down every 2 seconds,,0.7v->3.7v U3 and 0.7->1.2v UD1,,,, any ideas,,anyone have the diagram ??

[sansonet]

Re: Vizio VP322 - no power, blown resistor and fuse

Those boards dont look like ones from VP322 model - if you have different model, you probably should start your own thread...