OK. I've had this Plasma TV for almost 4 years. I have an extended warranty, and about a year ago I noticed red sparkles (kinda like pixel misfires) in grey scenes on the bottom 1/3 of the screen. I had it serviced under warranty and they have replaced the Y-Board and 2 Logic boards and still no go. I was about to call them again and complain, but after Googling I found that this was a VERY common problem for Samsung panels. The fix seems to be adjusting the VScan pot. In frustration, I opened the sucker up and used a multimeter to verify Ve, Vs, Vscan and Vtest. Some of the results were barely off from the sticker (Vset for instance started .6 high and rose to .9 high as the unit heated up). I set all four to what the sticker said, but no luck. I then began lower Vscan (as suggested) and the problem got better.
I am referencing SDI_PDP_2K5_312278514993_EN.pdf in the Philips SDI panel repair guides. Figure 6.2.8 PSU 50" HD v4 is my unit. My Vs is 200 even. My Ve is 70 per the sticker (not sure why repair guide says 100). My Vset is 195 even. I adjusted VScan from -175 to -170 and that cleared it up. I still have an occassional red pixel misfire in dark scenes, but nowhere near as bad as when it's at -175. I tried lowering all the way to -165 but it never seemed to cure the occassional misfire so I raised it back up to the point where the screen was clear.
The million dollar questions are: How low do I take the VScan (safely) and will it every stop the occassional misfire? Is there another adjustment I can do (Ve, Vs, Vset seemed to have no impact)?Should I raise Ve to 100 per the service guide or leave it 70 per the sticker on my panel? Does Ve have any known impact on red sparkles? Is my panel just going bad or my PSU (I have to assume the PSU is good because I get accurate readings from a multitester). Any help would be appreciated.