Quoted from fossmin:
Yes that happened removing the remote battery holder. Problem existed before the contact came off.
Broken terminal likely puts the batteries out of circuit.
Just thinking some more.... if it was a battery issue the game would be saying "ADJUSTMENT FAILURE" or "RESTORE FACTORY SETTINGS". The RAM fail message may be indicating the ram chip is indeed bad or it cannot be accessed.
Circuit board likely needs serviced one way or the other. I don't think the broken battery terminals is going to work out despite the ram fail message. How can batteries be in circuit reliably when the contact is busted off? Take Tony's advice in a comment above. Power supply problems can give you IC failure message in system 11. Usually a PIA fail message, but worth checking.
If you want to check the batteries are in good take a volts DC measurement across pin 12 and 24 of the battery backed 6116 RAM chip. If missing probe points backwards towards the battery terminal, like across the terminals with busted contacts.
I don't service boards anymore. Normally point people to Jerry C and he takes good care of it. His contact info on pinrepair.