Museum of the Game® & International Arcade Museum® Forums

Hi all, I am currently working on a Stargate PCB, and it had the dreaded 1-3-1 error. I have replaced the ribbon cable, burned all new EPROMS (2532s), new Decoders, new CPU, and did the 4164 RAM upgrade. However all I can get is a repeating rug pattern that has vertical lines in it, as well as the 1-3-1 on the segmented display. All voltages are within spec apart from the +12v being a little high at 12.6v. I have tested the 74153s and all outputs are pulsing correctly. The Williams schematics I have are very blurry and I can't read what pins do what on each chip or I would have tried tracing the issue already. Any help is much appreciated! Thanks all, anyone have any ideas?