Calcuscribe portable keyboard - battery damage

I got this portable keyboard called a "Calcuscribe" which is really neat looking. Unfortunately, it had a fatal flaw in its design: the battery compartment had openings to the main circuit board.



It wouldn't power up so I opened it up and found multiple spots of leaking battery damage. The bane of my existence are leaky batteries.

Putting 3 fresh AA batteries and pressing the power button didn't do anything. A power port is present, and plugging a 5v + tip power supply makes the display light up but it's all a smeary mess, but it does look like it's alive and doing something.

It should be a rule that a device should tell you what power you should be supplying. I felt confident that 5v would be ok, since it looks like it can be powered by a keyboard cable.

Anyway, it has some interesting chips on board: a mitsubishi 37702 (a 16 bit 6502 variant) and what looks like the rom, in a socketed windowed eprom 27c801.

Maybe I'll get a eprom programmer one of these days and read the thing.