Samsugn PN60F5500AFXZA, dark screen with color speckles

[Truncatedhose]

Hi everyone! The last time I worked on one of these, I had shutdown, but this time, it's acting like a bad X-Main; I'm wondering if anyone knows any tests I could do to confirm it? The pictures of this model's boards can be found here on the first post of this thread:

https://www.badcaps.net/forum/showthread.php?t=59567

Haven't found any missing or low voltages, but haven't checked EVERYTHING. VS, VA, VE are good. TV has audio and when you bring up the menu or any OSD, it brings up all the colored speckles and distortions in that area of the screen. It looks like the typical X-main (Z-SUS) failure we see on all plasmas, but want to make sure....?

[Truncatedhose]

Re: Samsugn PN60F5500AFXZA, dark screen with color speckles

Update: I found two open resistors on the YSUS and I did some checking in my tip Database under a similar model with "poor picture" symptom (which is not very precise) and found this:

"Upon Opening Up The Set We Noticed R5084 & R5097 On The Y-Sus Module Were Burnt. These Are Both 47 Ohm 2 Watt Resistors

These Feed The Lower Buffer Pins Labeled Vcsh . On The Lower Buffer There Are Several 30 Ohm 1/2 Watt Resistors That Appear To Feed Each Scan Ic. 2 Of Them, R5504 & R5506 Look Like They Got Abit Toasty!

Pulled The Lower Buffer And We Measure A Short Across The Big Poly Film Caps C5530 & C5532. Lifting A Lead On Both Those 30 Ohm Resistors...The Short Goes Away. They Feed 2 Pf The 6 Scan Ic'S...So They Are Bad.

Replacing The 2 Resistors On The Y-Sus And The Lower Buffer ( Part # Lj92-01963a ) Restored Proper Operation"
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I pulled the my buffers and tested those resistors and the caps and they were all good. I also did the buffer short test and found the UPPER had a short, but I think I will just replace both buffers for prev. maintenance.

[Truncatedhose]

Re: Samsugn PN60F5500AFXZA, dark screen with color speckles

Update: I replaced both buffers and the two resistors on the YSUS, now the picture is much better and you can see video, but it still has the colored speckles and massive grain and picture is darker than it should be.

I'm really scratching my head now. Any help from anyone?

[Truncatedhose]

Re: Samsugn PN60F5500AFXZA, dark screen with color speckles

Something else may have failed on the YSUS when the resistors failed, but what? I do notice that when I'm running the set, those newly replaced resistors stay cool, which is suspect. My VS, VA, VSC and VE are all correct and don't drop. What can I do?

[Truncatedhose]

Re: Samsugn PN60F5500AFXZA, dark screen with color speckles

Anyone?

[dskall]

Re: Samsugn PN60F5500AFXZA, dark screen with color speckles

Maybe a picture of screen