Need Pacman help

tng25

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This Pacman board was previously working fine, now it has some colored lines at the top and bottom of the screen. It seems to show up wherever there is text and is also affecting the power dots that now have stripes through them. The attract screen has the lines on all the text when it's listing out the ghost names. Any advice on what may be causing it and a possible fix?
Thanks.
 

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Try removing the edge connector from the PCB, and cleaning the edge with an eraser.

Always a good place to start.
 
Ok, I've cleaned the edge contacts and swapped in a known working vram addresser board, but the lines are still there. Is there something else I can try?
Thanks!
 
There may be a problem with how the VRAM address card connects to the rest of the board. Bad socket, broken solder joint, etc.
 
FIXED!
I tested for continuity from the solder points on the top of the VRAM board through the socket to the solder points on the bottom of the main pcb and it all looked ok. So I kept working my way down the traces until I got to 3R (74LS161AN). The legs were rusty and black so I took it out and cleaned it. Reseated it and the colored lines went away.
Thanks for the help!
Torin
 

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3R had nothing to do with the problem you were seeing. It just generate sync counts.

Chances are the real issue is a bad socket connection at 5E.
 
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