Help to repair an HP91

[isanchez]

Hi,
Today, I have recieved an HP91. It doesn't work propertly: when turned on, the display shows ramdom segments on without sense (not so many, just concentrated in two or three digits, the minus always is on and the low battery led also always on). These segments change when any or many keys are pressed (the full display on is never shown). Also the printer prints randomly from time to time, without sense....what do you think this can be? Could be the famous ACT? I have some Woodstock that can be used as spare parts.... but the diagnostic looks very pesimistic: it seems fully "fried" ;-C.

No signs of corrosion anywhere. It looks externally pretty good.
The printer tracking rolls are in bad state, but this does not worries me...

thanks in advance for your help.


Kind regards


Ignacio