AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

[rudedog9d]

First off, Hello All!! I need some help on a rather hard to search for problem.

I bought a Plasma TV through a craigslist style situation that the lady claimed had a foggy image. I've never worked on a plasma, and don't know much about them, but I figured for $20 why the hell not.

The power supply was a suspicion of mine from the start, as I have worked on several LCD monitors and a couple LCD TV's. Got it home and it wouldn't turn on, the light just flashed, and it had some mega bulged caps. (The board was actually melted under one of the caps, See Pictures). I replaced those, went to turn it on, and it fired right up, but it had some pretty weird stuff going on with the image. (Again, see pics)

Any Suggestions guys? I've been reading some forums, but I keep getting a bit lost in the talk of different boards, and Y-sus and y-buffer, ect.

Any help or guiding in the right direction is highly appreciated!!!
-Brodie Davis

Pics: First is where the bulged cap was.
Second - When you first turn TV on
Third + Fourth - Menu
Last -General static on "TV" Source. Can clearly make out "Ant 2" in the corner

[vinceroger69]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

can you post clear pictures of all the boards that are used in the set as we may then be able to help sort some points to test thanks.

[audiofreak19]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

I'm gonna guess either t con board issue. Or maybe I'm not sure who or what kind is in the t con board but maybe the gamma chip. Will need pictures of the t con board the one that has the ribbons that go to the screen.

[vinceroger69]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

is this a plasma ? or lcd ? i think its a plasma as youve mentioned the various boards when tom or one of the more experienced members with plasma fault finding im sure they will advise im more into lcd sets.

[rudedog9d]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

Ok, Here's all the boards. And Yes, It is a Plasma.

[Caleb]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

Im not the plasma expert that Tom is, but it looks partly like really bad snow caused by out of whack voltages, have you verified all the voltages are matching the panel sticker?

[tom66]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

Pretty ancient Samsung panel in that thing; I'm not sure where you'd test the voltages but my guess would be bad Vsch voltage.

[rudedog9d]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

Thanks, I will check as soon as I can. What's the best course of action, assuming the voltages are off? As I said, I already replaced two bulging caps.

Thanks, Brodie

[Caleb]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

There is a small potentiometer for setting each voltage somewhere, va and vs are usually on the power board all the rest usually on the ysus. Your challenge will be in finding the right one, there is typically labelled a test point and a nearby pot controls it. I circled some likely candidates on your picture

[rudedog9d]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

So I checked voltages tonight, and could only find a couple that were listed on the sticker. They all seemed pretty close to what the sticker should be, except I kept getting 0 on the Ve Line.
The following tested within 1.5v (Usually ~.7 high) of the sticker: Va, Vs, Vset

I couldn't find Vsc, which I was looking for because someone had mentioned that he thought the Vsch was off. I could only find Vscan on the power board, which was ~30v.

I've included some more close up pics. The first three are the power board, the two after that are of the board on the left, and the last is just of the sticker I was going by.

Any Idea's? Or see where I might have missed something?
Thanks, Brodie

[Caleb]

Re: AKAI PDP4294 Plasma TV displaying Weird images after Cap replacement

I found the service manual and it does go through voltage setup, however it appears to be for different boards than reside in your tv so I am not sure how helpful it will be.