May want to clean and/or repair that analog board before you blame the logic board.
Otherwise, run fairly warm water over the logic board while lightly brushing with a medium toothbrush to remove light corrosion or anything else that's not supposed to be there. Then let it dry for a week before inspecting for damage such as broken traces, broken pins, missing stuff, etc. If it doesn't work after a thorough cleaning and any required repairs are performed, then you'd have to go much further in depth to discover the source of the problem.
Or you could set it aside to use as parts. Sad fact is, even solid-state integrated circuits will die, and there's nothing you can do to repair them; the only course of action is to replace the affected chip or the entire assembly, depending on how comfortable you are with sensitive work and if you can find replacement antique microchips.
Otherwise, run fairly warm water over the logic board while lightly brushing with a medium toothbrush to remove light corrosion or anything else that's not supposed to be there. Then let it dry for a week before inspecting for damage such as broken traces, broken pins, missing stuff, etc. If it doesn't work after a thorough cleaning and any required repairs are performed, then you'd have to go much further in depth to discover the source of the problem.
Or you could set it aside to use as parts. Sad fact is, even solid-state integrated circuits will die, and there's nothing you can do to repair them; the only course of action is to replace the affected chip or the entire assembly, depending on how comfortable you are with sensitive work and if you can find replacement antique microchips.