samsung sp-r4212 plasma picture problem

[Sevenqi]

Samsung sp-r4212 plasma picture looks as photos, it's dark but as not as darker as the z-sustain board failured. I checked the VS and VA, normal, the fuse on the z-sustain board, not open.
I tried: adjusted the resistors on the z board and the y baord, but no changes. What's next ?

[tw2005]

Re: samsung sp-r4212 plasma picture problem

I'm thinking that could be either a mainboard or logic control board issue. I believe the logic board can be jumpered with the mainboard isolated to generate onboard test patterns or you should be able to access the service menu and generate tests in there. You could also try the different input sources, tuner, av in etc and see if you can get a change.

Off the top of my head i can't tell you exactly, it does not look dark in the photo although those skin tones in picture one could be an incorrect adjustment on the Ymain. I have seen something similar whilst playing with adjusting a ymain once on a Samsung but I'm not able to explain it better. I'm sure Tom will have a better idea.

I avoid touching those pots as I find it difficult to get them right and an oscilloscope is usually the correct way of setting them.

[Sevenqi]

Re: samsung sp-r4212 plasma picture problem

Thanks TW2005, I still have no idea how to adjust the y board.
I had another LG 50" (50ps60), the same problem, but brighter than this set, I adjusted the VS,VA and all the VRs in the y board, I got better picture (watchable) finally, but couldn't get rid of the red dots, it would take 2 hours power on to disappear.

[tom66]

Re: samsung sp-r4212 plasma picture problem

The Y-main is first adjusted by getting all voltages in spec by comparing against the panel sticker.
Then if that doesn't sort it, play with Yrr and Yfr.