Originally Posted by wdaveweaver
I am having the same issues with my Samsung HPS5053 and the Red Dancing "Snow" Pixels on the dark scenes. I have narrowed down the problem to probably the voltage adjustment. Does anyone know where the voltage adjustments on this panel are located behind the backing and any recommendtations on adjusting them, like can you do it while the set is on to see the difference in realtime? I am pretty knowledgeable about electronics and have done adjustments on other devices before, so I am willing to do this myself as I am just out of warranty. Also, does someone have the service manual for this model as it would be helpful for this and future tweaks? Any help is much appreciated.
I just read the various threads on this issue as I was having them myself. My Samsung is almost 2 years old and wanted to get it fixed under the credit card warranty if it was a board. However, I know how much of a pain it was going to be after getting another item fixed under the plan. So, I decided to check out the voltages this evening (I am an amateur radio operator and just about everything I own has been opened at one time or another).
It took about 45 minutes to disassemble, check, adjust and re-assemble. I found that most of the voltages were very close, but the one that did the most to remove the dots was VSc (or Vscan). The sticker (upper right side -- you can see the sticker through the vent) said VSc should be -185V. It was -188. I adjusted it down to get rid of the dots (which was at -180V -- another posting said +/- 5% was fine). I also tweaked the others to match the sticker -- the remaining ones were only off 1V or less.
To do this, you will need a DC voltmeter that can measure at least +/- 200.0V with good isolation (don't try it with a $5 unit you got at KMart), a jumper with clips on both ends (to ground the negative probe lead) and a potentiometer tuner which is a non-conductive rod (you can use a screw driver but put tape over the metal shaft so you don't slip and short something out). On the 5053, three of the test point 'discs' are on the top of the board 7 inches to left and 7 inches down from the sticker. The potentiometers are on the left side of that same board. The other two potentiometers are located on the large board to the left of the above board; these test points are small hollow 'tubes ' coming out of the board and are marked with TP (for test point, of course). They are harder to see and I didn't memorize their location; just look around. One is very close to the potentiometer, the other one is not. I didn't notice one voltage adjustment affecting the others so it does not matter which you do.
ONE NOTE OF CAUTION: do these adjustments at your own risk -- there are obviously high-voltage circuits on these boards and if you touch them with bare skin or a metallic object, you are going to get bit :-) Also, it does not take much of a turn to vary the voltage -- a '1 o'clock' movement (e.g. 3PM to 4PM) can make a 20+ volt change. You REALLY need to turn the potentiometer VERY SLOWLY while watching the voltmeter. Going to far could fry a key component.