CurtPalme.com Home Theater Forum

jbryngelson · Joined: 02 Jan 2008 Posts: 14

Hi guys, My good friend, John Gannon and I swapped Minty tubes from a flakey XG85 into a XG135 that had tubes with burn-in. All went pretty well, adjusted the G2 POT for the Green Tube (It was running really hot), but now I have a really weird issue.

There is a curtian like affect when I bring up the brightness, or any of the Kelvin Adjustments for brightness. I found this when following the G2 reference setup process. It looks like a curved screen accross the face of the CRT as I bring up the various brightness/kelvin settings.

Frustrated, I went and setup an new input for S-Video, and connected that way, thinking it might be something in the cabling/switching/converting chain, but NO, it was there too.

I will post pictures tomorrow, but wanted to get your thoughts..

Jeff

Mark_A_W · Posted: Sun Jan 17, 2010 4:48 am Post subject:

Sounds like the back raster is showing, which means the BLKG (pedestal) pots need adjustment, which is part of the white balance.

If it's coming on when Brightness or Kelvin controls are active, then the AKB system is revealing it, which is strange.

If it's not there during normal use (no akb), then I would leave well enough alone.

jbryngelson · Joined: 02 Jan 2008 Posts: 14

Hi Mark,

I am confident the pots are not quite right, so your analysis is spot on. I have been through the G2 process, and I am finding this issue does go away when I complete the measurements and G2 process on the G and B tubes, but not the red. Any suggestions? Is this as easy as reducing the Red G2 POT on the video out board?

jbryngelson · Joined: 02 Jan 2008 Posts: 14

So, it took some serious tweaking of the Reference Kelvin settings, the RBias POT, and I now have it set, with only one problem, my Red tube is running at 2.8v instead of 2.5v. Blue and Green are settled in fine at 2.5.

Still a really weird problem. It was like there was raster that lit up a bit, then the image lit up, then there was a curved curtian the was higher and lower than the image, but narrower.

Not a dream, but really what went on in my red tube!

Mark_A_W · Posted: Sun Jan 17, 2010 10:07 pm Post subject:

Pretty sure it's the Red BLKG pot...which sets the pedestal level, that you need to set using a scope.