Texas Instruments PC-200 printer

[Jonas Sandstedt]

I recently bought a PC-200 printer for my TI-66 calculator.
It was damaged by battery leakage, so I cleaned and partly re-soldered where it seemed needed.
The printer then functioned and printed as it should for a few days, but then suddenly the printhead started to run from right to left to right etc, just feeding the paper. Sometimes it stops anywhere, but mostly the batteries have to be removed to stop the motion. Sometimes it starts without the calculator being connected (when the batteries are inserted), and sometimes when a printer command is given from the connected calculator. For a short time the printer suddenly started to work as is should, but the next day, the printhead started running again and now sereral weeks have passed without any progress.

I have checked the working of the feeder mechanism and the sliding contacts at the left that control the position of the printhead, and there is contact everywhere where I think it should be.

The feeding voltage for the ICs is 3,0 V (correct?), the batteries are fresh, and I have replaced them once to be sure.

I understand that is difficult to give advice, mostly I wonder if there are any schematics or other service information available for the PC-200 printer? Perhaps someone has spare parts to sell?

Jonas Sandstedt