CurtPalme.com Home Theater Forum

[deewaan1]

[JustGreg]

This sounds like an 8500 I eventually parted out. I never could find the source of the problem although I suspect it was motherboard or backplane board related because they're the only things I didn't replace with known good parts.

What's most interesting in your case is that when you worked with the HDM and VIM you ended up with all THREE tubes exhibiting the same problem as your initial blue tube problem. That sounds to me like a harness or HDM/VIM socket problem.

I'm running the life out of a blue tube right now that I knew when I installed it a month ago would require high G2. It's somewhere around 84 or so but my brightness and contrast are 50 and 44 respectively with good greyscale. PS3 and Xbox360 look great. Do you have any gamma correction goodies in line? (You didn't say which Moome card you had).

When the thread started I thought the same things as the others and then got to thinking it might be a bad mini coax but you blew that theory away by reporting you'd managed to create the issue on all three tubes. The little buggers (mini coax) are easy to break without just the right twisting and coaxing of the 90 degree mini RCA connectors.

Out of curiosity, did you use a lint free cloth or Q-tip to clean the chips and sockets, or a paper towel? Paper towels are the absolute worst thing you can use. You're better off using an old T-shirt than a paper towel. I'd go back to the HDM and VIM and re clean everything again if for nothing else than to see if you can restore the set to the blue tube only problem.

Worse comes to worse, I'd tear it down to the frame and check continuity from the sockets thru the harness and on to their card edge terminations at the LVPS and HVPS, backplane etc. The others here can suggest ways to check the motherboard and backplane. A broken trace or bad solder joint isn't out of the realm of possibility either.
Wiggle the wires at the connectors while connected to your DVM and mark each successful one with a paint pen or the like so you don't lose track of what you've done.
Hmmm. A strange one for sure.

[energeezer]

[deewaan1]

Hey all. Thanks for all the help so far. Still got the problem though. Here's what I've done since the last communication.

I've completely taken the projector apart an cleaned all connections ( connectors, chips and sockets, cable terminations ) from every board including the neck boards. I've tried swapping the HDM, Focus board, VIM, Color Correction, Conv board, Verticle board, Astig board, Video/S-video input board, Moome card, CLM board, HVPS, LVPS. I have also swapped the neck boards between the three tubes. I even tried swapping the ribbon cables to the back panel boards. All this and nothing still has the same issue. No improvement. Tomorrow I am going to get another high voltage splitter and try that. I am also thinking of trying to disable one tube at a time and see if one tube is possibly sending some feedback into the system which is causing the second set of scan lines. What is the best and safest way to disable a tube and still be able to power up the projector to see if the other tubes are still affected?

[Nashou66]

Some marquees will power up with the black umbilical VNB cable disconnected. it will run for a few minutes so you can see which tube is causing the problem. I havent read this in awhile so I forgot what the problem was!!

Athanasios

[draganm]

[Nashou66]