HP-67 - 1612S04538 - motor slow and wrong resistor value

[albertofenini]

Hi everyone, this was weird ...
It had the card reader motor running very slow, when connected and also when taken out it was barely running.
We used then a spare motor, but again when we connected it to the HP67 it was too slow to pull a card.
This HP67 is using an HP65 style card reader, we removed the resistor on top of the card reader and replaced it with a trimmer,
after some tests (this is when we used a different HP67 standard pac) we got it working in reading and writing.
We will need now to measure the trimmer value and replace it with a resistor.
BTW Has anyone ever opened a card reader motor and cleaned the inside ?
Pictures here : HP-67 1612S04538
As always, any advice is greatly appreciated,
Thanks for help !!!