G07 Monitor - Ms. Pacman - "Red" color issue...

Highway90

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G07 Monitor - Ms. Pacman - "Red" color issue...

Background info:
-Original 1982 Ms. Pacman
-G07 Monitor

1) just had a new cap kit installed and chassis board tested
2) Used a Degaussing coil to cure some color spots

As seen in the photo I cannot get any "pacman" yellow to show. Everything has a red hue to it. I have tried all the monitor adjustment knobs on the neckboard. I also checked the wires from PCB to monitor chassis.

Advice?
Tube gone bad?
 

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Have you tested this monitor with a different game? If you turn up the green drive and the green bias pots, you should get a green background. Do you? if not, check your green drive transistor for cold solder or proper function. You may alos need to check the tube, or maybe the green pin on the neck got bent when installing the neckboard.

The reason I ask is because - you said you had a cap kit installed and chassis tested, which makes it sound like you sent it off for repair. You could still have a bad green gun on your tube, or the green drive on the neckboard could have come messed up during return shipping or installation.

If you HAVE tested it on a different monitor, and know for sure that the problem is with the Ms. Pac board, I'd check to make sure the edge connector pin for the green signal is making good contact. It's easy to figure this out. Just use your volt meter and measure the DC voltage between the green wire and the ground wire at the video input connector to your monitor. It should show about 2.3 volts, I think...
 
Thanks for all the help!

1) Yes, the chassis board was sent off and fully tested on another monitor.
2) If I turn up the green. its a big green background. no problem there.

Well, looks like its a an issue with the Ms. Pac PCB. I will send off for the 2A, 4A, and 7F chips this week.

Hmmm. I still haven't removed the original filter board. Might try that first...
 
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Well I removed the original 4A and 7F proms and reseated them. Looks like that kinda fixed the color issue. Ghosts, fruit and pacman look great.

Now the "maze" is looking crazy. Hmmm...

Any new advice?
 

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