Panasonic TH-50PZ80U: major case of the sparklies

[the_meter413]

My Panasonic plasma (TH-50PZ80U, manufactured in 2008) seems to have a major case of the sparklies (see attached image). Blacks and greys below a certain threshold appear as bright greens. Before I order a refurbished power supply, can anyone offer any suggestions for what else I might try, or validation that it most likely is the power supply board?

I followed as much as I could of the tom66 thread on troubleshooting in combination with Panasonic's service manual for this model TV. Per Panasonic's instructions, I queued up a solid white image, and adjusted Vsus, Ve, and Vad (these are the only three adjustments available) to within +/- 0.01 V. The set worked fine for a few days, then the sparklies came back. Checking the voltage values again, I noted some drift (can't remember specifically how much, but definitely out of acceptable tolerance).

[tw2005]

Re: Panasonic TH-50PZ80U: major case of the sparklies

maybe post what the voltages are in comparison to the panel sticker. Also I think these have a LVDS cable that go to the d board, try reseating that at both ends (A5,D5)

[tom66]

Re: Panasonic TH-50PZ80U: major case of the sparklies

The PZ80s have a few issues with the LVDS cable coming loose. So as tw says, I'd reseat it both ends. It looks a lot like that. Sometimes half the display will also go black - it depends on the exact fault. It doesn't look like wrong voltages.

[the_meter413]

Re: Panasonic TH-50PZ80U: major case of the sparklies

The PZ80s have a few issues with the LVDS cable coming loose. So as tw says, I'd reseat it both ends. It looks a lot like that. Sometimes half the display will also go black - it depends on the exact fault. It doesn't look like wrong voltages.

Thanks tw2005, tom66,

I *think* I identified the LVDS cable on my board. Do the arrows on the pics below look accurate? If I'm reading Panasonic's schematic correctly, the LVDS cable goes from the D board to the A board? Indeed, it didn't seem to be seated properly on the D board - not horribly misaligned, but definitely not a snug seat. I'm also seeing that this cable is quite different from many of the other cables in the board. The wire and insulation appear to be a lot more rigid than a lot of the other connectors. Is it worth replacing the whole cable assembly? Or somehow testing it? Basically, I'm just looking for any additional things I might want to consider while I have the set gutted.

Thanks again for your help. This forum is an awesome resource.

[tom66]

Re: Panasonic TH-50PZ80U: major case of the sparklies

Yes, that is the LVDS cable.

[tw2005]

Re: Panasonic TH-50PZ80U: major case of the sparklies

you'd be lucky to get that cable. if reseat works then you could get some gaffa tape and cut a strip to put across the joints to keep it secure. might be worthwhile reseating several times to clean the contacts up.

i had an old 2005 panasonic with a bad joint there and that sorted that out until it eventally kicked the bucket

[the_meter413]

Re: Panasonic TH-50PZ80U: major case of the sparklies

About 12 hours of viewing since reseating the cables, and no evidence of the issue. Fingers crossed. Thanks again for all the suggestions.