I think it's too early to tell if your problem with Andromeda is on the MPU or elsewhere in the game. If you get a new MPU without properly diagnosing the issue, you may end up blowing the same resistor on the new board.

Also, the echo lake MPU had a problem with working in either Andromeda or Cyclopes--I can't recall which exactly. Can anyone confirm?

If you have an EPROM burner, you could probably figure it out how the individual ROM images were combined and burned to the EPROM by reading it and comparing it to the original ROM files on IPDB.