Electrohome G07 CBO with "snow"

[kid sinister]

I'm working on a Centipede machine with an Electrohome G07 CBO monitor that has an nnoying problem with the picture.  The problem is that the picture has a "snowy" effect of moving white dots across the screen.  The picture looks great except for those dots.

So far I've tried a cap kit, replaced the HOT, resistor R908 and the horizontal width coil (since I accidentally broke the old one ).  The snow is still there.

I noticed that I can make it less noticeable if I turn down the brightness knob on the flyback, but then all the other colors get dimmer too.  How do I stop the snow?

[grantspain]

sounds like some kind of mains interference,had a similar problem on hantarex that turned out to be the way the marquee light was wired-mine had the light wired to the same line as the monitor input voltage thus causing interference

[kid sinister]

sounds like some kind of mains interference,had a similar problem on hantarex that turned out to be the way the marquee light was wired-mine had the light wired to the same line as the monitor input voltage thus causing interference

So if that's true, then the problem should disappear when I unhook the light, right?  I just tried completely detaching the ballast and I'm still having the snow problem.

[kid sinister]

I think I just fixed my problem.  The reason I didn't want to turn down the brightness was because it would make the colors dim.  Well, I turned the brightness down enough to make the snow go away and I took a closer look, and I noticed that only the reds seemed dim.  So I turned up the red knob on the neck board, problem solved!  I must've nudged it or something when I did all of the soldering work.

[Justin Z]

Heh that's cool.  I remember getting snow on CGA PC monitors way back in the day when you'd do fast screen updates -- the snow was caused by the cursor moving quickly (but not quickly enough) across the screen and "redrawing" (retyping, really) everything.

Glad you got it fixed!