My parents' Panasonic P42S30 died recently, and they asked me to have a look at it. I was able to identify the SN-board as the culprit, as it was shorted. After removing Q401, Q402, Q421 and Q422 the short was gone, so I replaced these components and that got the TV working again. However, when testing the tv a bit, I noticed quite bad pinkish sparkles on some colors. For instance the greyish bar on this forum seems to trigger it quite badly. I made a fullscreen test picture with only that color, with the below result.
There is about a 5cm high region at the top without any sparkles, immediately below that it is the worst and then it fades out towards the bottom. I don't really know if this was already present before the repair, because it's not my tv and with normal content it is not super noticable (and my parents' eyesight is not the best anymore). The image retention also seems quite bad, but I haven't had a plasma for a while, so I don't know if it is normal. Finally, there is a test pattern in the service menu that is listed as 'LOW STEP WHITE' which is just black with a lot of red and green sparkles on this tv.
I read on this forum that this might be Vsus related, so I measured it and it was 211V. The service manual said it should be 215V, so I turned the Vsus pot until it was at 215V, but that did not make a noticable difference. I also set Vsus to high in the service menu, also without result (apart from the brightness increasing a bit). I then tried to see if any normal settings would make any difference, and found out that setting the Intelligent Frame Creation to Max, the sparkles were reduced a lot! I could just leave it at that, but I would rather have an actual fix for this. Any ideas what might cause this?
There is about a 5cm high region at the top without any sparkles, immediately below that it is the worst and then it fades out towards the bottom. I don't really know if this was already present before the repair, because it's not my tv and with normal content it is not super noticable (and my parents' eyesight is not the best anymore). The image retention also seems quite bad, but I haven't had a plasma for a while, so I don't know if it is normal. Finally, there is a test pattern in the service menu that is listed as 'LOW STEP WHITE' which is just black with a lot of red and green sparkles on this tv.
I read on this forum that this might be Vsus related, so I measured it and it was 211V. The service manual said it should be 215V, so I turned the Vsus pot until it was at 215V, but that did not make a noticable difference. I also set Vsus to high in the service menu, also without result (apart from the brightness increasing a bit). I then tried to see if any normal settings would make any difference, and found out that setting the Intelligent Frame Creation to Max, the sparkles were reduced a lot! I could just leave it at that, but I would rather have an actual fix for this. Any ideas what might cause this?
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