Solved!! Gauntlet sprite issues

So unfortunately this suggests one of the customs has gone bad. The graphics are 4 bits per pixel and each custom handles 2 bits (each ROM supplies 1 bit which is why they are in sets of 4).

Because the colors changed when the customs were swapped different bits must be getting through. If both customs worked then there would have been no chance after swapping them.

So to verify - swap the customs back again - is the original 'brown' look back? Any broken legs on the chips? Or dirt/corrosion in the socket?

To check the ROMs dump them and compare the checksums to the MAME ROM set. However they are probably good as per the logic above.
 
I'll test them again later and let you know. As far as the customs go, there's no way to verify them as well is there? How difficult is it to find a replacement?

So unfortunately this suggests one of the customs has gone bad. The graphics are 4 bits per pixel and each custom handles 2 bits (each ROM supplies 1 bit which is why they are in sets of 4).

Because the colors changed when the customs were swapped different bits must be getting through. If both customs worked then there would have been no chance after swapping them.

So to verify - swap the customs back again - is the original 'brown' look back? Any broken legs on the chips? Or dirt/corrosion in the socket?

To check the ROMs dump them and compare the checksums to the MAME ROM set. However they are probably good as per the logic above.
 
Ok, solved!! It was the Atari custom 137415-101 at location 2k that caused the issue. Huge thanks to all who helped me and especially to Tendril for pegging this down fairly quickly. You guys are awesome! Hopefully this thread will help others down the road. Now onto the joysticks!
 

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