Panasonic TH-42PZ77U blue clouding on white screen

[LimeGT]

Hi, I just started having an issue with my plasma. If watching say a hockey game with white ice I get floating blue tinting on the white. I also noticed on peoples faces there are grey patches over their skin tones. I can also see the front panel grid board outlines in the patch areas. I'm wondering if it's the D board as the issue is more pronounced in the center of panel but covers the whole screen depending on scene.
The pictures attached don't really show the intensity of what I see.

Thanks

[LimeGT]

Re: Panasonic TH-42PZ77U blue clouding on white screen

Went to test screen mode. White screen shows blueing in center.

[Biruslapio]

Re: Panasonic TH-42PZ77U blue clouding on white screen

Panel aging, try increasing VSUS(ඞ) in the power supply in incremental small adjustments until it disappears, don't go over 5V of the original value.
You can also set VSUS in the service menu to "High".

[LimeGT]

Re: Panasonic TH-42PZ77U blue clouding on white screen

Thanks, I'll try the service menu first so I don't have to remove a pile of screws to get the cover off again. I did check the VSUS voltage on the board a few days ago and it matched the ratings on the sticker label so I left it as is.
I did read this sticky on plasma's but it didn't seem to list my issue. https://www.badcaps.net/forum/showthread.php?t=18542&

[Biruslapio]

Re: Panasonic TH-42PZ77U blue clouding on white screen

Yes, messing with VSUS is the first thing to do because it is the easiest, if it does not work, then inspect SC and SS boards for cold solder joints, and clean connectors that have dust or dirt, these TVs are old.

There are other voltages to fine tune, VE on the SS and VSET on the SC, default VE value is printed on the panel sticker, VSET is 365V ± 7V, the others shouldn't affect picture quality.

[LimeGT]

Re: Panasonic TH-42PZ77U blue clouding on white screen

I'm baack; After multiple days of trying to figure out why changing out the larger 56uf and 68uf capacitors on the D and DG boards would cause a SOS code I found the problem. A minuscule drop of solder welded itself between 2 terminals on the FL304 feedback capacitor on the D board. I decided to change the caps on the D board, with nothing to loose, because unplugging the DG board made no difference to picture quality. Changed out the DG board as well because I had it out. As of now the bluing is gone so I've made adjustments as you've suggested. All adjustments were in spec except TPVSCN. It was 6.34V and my calculations VSCN +148V minus -139V Vad = 9V. I adjusted up to 8.99V. Would you agree with this or would this be too large of a voltage increase that may do harm? I haven't had a hockey game on yet to test white ice for blue patching yet but Picture looks better. Hope it lasts for awhile.
Thanks

[Biruslapio]

Re: Panasonic TH-42PZ77U blue clouding on white screen

No one but you could find that tin drop, thankfully it's fixed.

First tune the voltages according to the panel, what's not on the panel is on the service manual, if the model is the same it's safe. Adjusting voltages is needed only if you swap boards that are from different panel revisions.

[LimeGT]

Re: Panasonic TH-42PZ77U blue clouding on white screen

Thanks for the reply. Yes, one mistake with the solder iron had put me in days of confusion. The SOS System Shutdown saved me from damaging the D board.

[LimeGT]

Re: Panasonic TH-42PZ77U blue clouding on white screen

Just a follow up. After a few heat cycles blue clouding is back. I may experiment a little more as I wait for a good sale on another TV. My knowledge of plasma troubleshooting is very limited. I did look up hours on set. 29000+.