Need some help with a busted Akai plasma

[gadget73]

Hi,
First post over here. I've got this 42" Akai PDP4273M that someone dropped off for me to look at. When it came here, it wouldn't turn on. I found some swelled up caps on the power supply aux board and on the board with the audio amp chip. Those have been replaced, and now it sometimes turns on. When it will not turn on, the panel lights up slightly, but thats it. When it decides its going to power up, I get the blue Akai screen, then it lets me select input, etc. It will produce a picture, but it flickers and has lines flashing across the screen. Video of this in action below:


http://youtu.be/F3Vw8dozp9c


Any thoughts on where to start with this?

[gadget73]

have I yet again come across a bizzare problem that doesn't make sense to anyone else? Must be my lucky day. I got to watch the conveyor system at work do funny stuff that I couldn't make it reproduce with anyone else watching either. We did finally figure out and fix that problem though. TV sets I do not seem to be quite so lucky with.

[Geoff Bourquin]

I looked at the Youtube vid. I don't recognize the problem. My best guess is maybe a noisy power supply. Are there any puked caps in the set?
It almost looked like the set was loosing sync for a split second. That could be just about anything. If the power is clean, my best guess (REALLY a guess!) would be something on the signal board. That is based in part on gut feeling, and in part because it didnt look like the OSD was affected, suggesting the problem is before the panel gets the picture

[gadget73]

I replaced the obviously puked caps, but I didn't get any more in depth than that. I don't have an ESR meter to check the remainders. I was also thinking possibly something on the signal input board is going flaky but I don't really know how to test it. I can stick the scope on the power supply output and see if that tells me anything. Would you think its more likely the low voltage DC area, or the HVDC output to drive the plasma itself? I'm hoping low voltage since I don't have an x100 or x1000 probe to be able to deal with high voltages on my scope.

[gadget73]

I messed with it some today and I only got it to actually power up properly once. After that, it would partially power but not actually "boot up" with the Akai logo or the ability to access any menus. My parent's very similar looking Maxent plasma did this same thing a few years ago, and it was the video input board. I'm thinking perhaps its the same situation with this. I found one for 60 bucks, but I'm a little hesitant to buy it and find out I'm wrong. No returns. Is there any way I can test this board before I commit to buying a replacement one just so I have an idea if I'm wasting my money or not?

If it helps, the number on the board is E3761-050020-1 Rev 01 2005.09.23

[yrly]

Looks like a mainboard/input board problem to me. Got a picture of the inside layout of the set?