CurtPalme.com Home Theater Forum

zephyrr · Joined: 09 Feb 2026 Posts: 4 Location: Washington

First time poster here let me know if I did anything wrong. I picked up a sony g90 along with spare tubes but ive run into an issue where the green bleeds / smears and if the contrast is too high (by this I dont mean im cranking contrast to max I mean even at like 50% or something) or the scan rate of the input signal is too high theres some black flickery stuff going on the screen, if anyone has some idea whats going on and how to fix it please let me know, the issue only happens with the green the red and blue are perfect, I can try and get a picture or maybe video of the black stuff tomorrow its just been discouraging so I havent touched the projector in quite a while so this is an old picture ive attached. [/img]

zephyrr · Joined: 09 Feb 2026 Posts: 4 Location: Washington

alright update, its not really black flickery stuff I remembered wrong I guess more like the bleed of the green kind of flickers a bit darker constantly and the spot it does that is constantly changing kind of like tv static

**Curt Palme** · Posted: Wed Feb 11, 2026 3:46 pm Post subject:

Haven't seen that before on a G90, but it's three things: (most likely)

-bad YA board
-bad video amplifier, the board sitting on top of the green CRT neck. Swap it with one of the other ones, to see if the problem moves to another tube.
-bad CRT.

zephyrr · Joined: 09 Feb 2026 Posts: 4 Location: Washington

will take a look soon im hoping its not the ya board that seems hardest to get at

zephyrr · Joined: 09 Feb 2026 Posts: 4 Location: Washington

alright I swapped the amp board for green and blue and the issue moved to the blue tube, will look into getting the board fixed soon, if anyone has a spare to sell or can fix it in wa let me know

**Curt Palme** · Posted: Fri Feb 13, 2026 6:15 am Post subject:

You'll likely need to buy a used replacement if you can find one. Board level repairs for the G90 pretty much died with me and Craig Rounds not doing it any more.

CIR Engineering · Posted: Tue Mar 17, 2026 3:53 am Post subject:

Hey Curt! I’m still doing G90 repairs. Pretty much for everyone in the world now Wink

. OP just bought a neck board from me.

He’s got what looks like contaminated coolant too. Do you recall where the threads are on DIY coolant. I found tech grade ethylene glycols on Amazon that is easy to get. I figure that at 50/50 or 80/50 distilled water should work as a fine substitute for “CRT Coolant.” I myself still have many bottles of actual coolant so I never have bothered with substituting.

**Curt Palme** · Posted: Thu Mar 19, 2026 12:20 am Post subject:

Oops, sorry! Smile