Help me with my Galaga and Millipede PCB issues!

Lescell

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I hava a Millipede that I'm trying to get working and a Galaga that was working and now giving me trouble.

The Millipede will reset within a few seconds of starting a game, every time. I replaced the Big Blue cap, all voltages are good (checked at the PCB) so I'm not sure what else may be wrong.. I'm still pretty knew to diagnosing board problems.

Galaga was working fine until the other day when it gave me a "RAM 2L" error. I was told it's not the 2L RAM that's the issue and what I've tried so far were voltage checks (a-ok) and re-seat / clean a bunch of socketed chips, and cleaned the edge connector (board side), not sure of the safest way to clean the harness connector pins though. What else could I try? Galaga also has a problem where it keeps itself in a reboot loop when I switch it to free play with with dip switches.. Any thoughts on that one?
 
Millipede probably has a bad pokey. The 2 40 pin chips right next to each other. Unfortunately these are expensive so it's best to verify by swapping in two known Good ones if you have any.
 
Figured out Galaga, and tried swapping one of those chips with a working one for Millipede but had no luck. Still trying to source a 2nd 40 pin chip but if anyone else has some idea, I'm all ears!
 
did you put it in test mode? and look for any error conditions?

by default it does a RAM check even without the test mode, I don't think it does a ROM check,but ROM check is done in test mode.
more than likely I'd think it's one of the POKEYS, which may or may not show up in test mode.
You might try swapping the POKEYS to see if the results change and it behaves differently.
(for example if it now no longer even boots, definitely a POKEY issue) it's also possible that it now doesn't reset but maybe is missing sound or something etc after switching, which again will confirm the one POKEY is bad.

Figured out Galaga, and tried swapping one of those chips with a working one for Millipede but had no luck. Still trying to source a 2nd 40 pin chip but if anyone else has some idea, I'm all ears!
 
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