CurtPalme.com Home Theater Forum

ICinRGB · Joined: 01 Aug 2007 Posts: 15

My 2002 9500LC has an unstable brightness or G2 level and it's been this way the whole time I've owned it, about a year. At times it will be stable but most of the time it fluctuates between, I'd say 10-50% brighter than its current setting, making blacks dark grey, flickering up to light grey. Lately the picture will shift to the left a little while the fluctuations are occurring and be slightly out of focus.
Parts I've swapped out, but only briefly:
CLM
VIM
HVPS
Focus Board
Ran without ACON and Contrast Modulation boards
I've insured that all tubes are grounded and the power jack it's connected to is grounded as well. I've also tried running with each of the tubes disconnected one at a time to rule out a neck board or tube malfunctioning issue. I run it without a case and it always seems cool so I don't think heat is the issue.
I love this projector and really want to to find a solution, any help is much appreciated!

Thanks,
Tony

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

The observation that the picture gets slightly out of focus with the brightness change indicates a G2 issue. You are sniffing in the good direction, since G2 control is originated on the CLM and is controlled on the VIM, and takes effect in the HVPS. A connection problem between VIM and HVPS could be suspected as well - sign of an old glycol leak?

ICinRGB · Joined: 01 Aug 2007 Posts: 15

Thanks for the response gjaky, and for the info. It hasn't had a glycol leak since I've owned it, but i did find a little glycol on the focus board when swapping parts around that I cleaned and resolved an unstable h-size issue. I haven't seen glycol anywhere else in the unit. Ok, I'll inspect and try to clean the connections you mentioned. Thanks again!

**Curt Palme** · Posted: Mon Mar 20, 2017 6:05 pm Post subject:

Use isopropyl alcohol to flush out under the 8 pin chip of the motherboard that sits vertically under the tubes that the main motherboard connects to. One tiny bit of glycol under that, and that can cause the exact problem.

ICinRGB · Joined: 01 Aug 2007 Posts: 15

Curt, will I need to disassemble the projector to access that chip?

Thanks,
Tony

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

ICinRGB · Joined: 01 Aug 2007 Posts: 15

Ugh. Sounds like I have a weekend project. Does anyone have a pic of this 8-pin chip? I haven't delved that deep into this projector yet.

gjaky · Joined: 05 Jun 2010 Posts: 2790 Location: Budapest, Hungary

If you remove the CLM and the boards over it (CMM and ACON - if you have) you can see it through the opening.

ICinRGB · Joined: 01 Aug 2007 Posts: 15

Oh, so the backplane. Ok, I'll get to work, thanks!

**Curt Palme** · Posted: Mon Mar 20, 2017 10:26 pm Post subject:

You can actually access it when it's floor mounted by taking out the red and green tubes only.

lydmann · Joined: 12 Aug 2006 Posts: 56 Location: Norway

I have same issue on my 1209/2, except the focus is not affected and Picture is not moving. but when I use blanking, the g2 is increasing-

Can it be the plug to the neckboard which need cleaning? Or is it gasy tube?