There are several (I forget the number, but maybe 6-8?) small and large aluminum canister capacitors on the 2300c logic board, clustered together to the left of the power connector. The largest ones are of a size to just about touch the top plastics.

I would bet on leaking electrolytics being the cause of the trouble. If so, then your Duo is much more easily repairable than would be the case if the onboard RAM has failed. The replacement capacitors are cheap and plentiful, water to wash the board is on tap, and though a small pain to disassemble, a Duo itself and a capacitor are really not that hard to work on.