Can you post a picture of the MPU board? I know we all would like to know you do not have any battery corrosion on the board, though likely you at least have corrosion on the battery holder terminals.
NVRAM is an easy upgrade on DE games as you pop out the old RAM and install the new NVRAM and gets rid of batteries forever.
https://pinside.com/pinball/market/shops/1030-pinitech/00315-6264-nvram-battery-eliminator-for-high-score-save