HP 67 Circuit Board

[metawops]

Okay, the good news ist: the MTRS switch works as can be seen in this little video I made.

https://www.icloud.com/iclouddrive/078a5...Cardreader

The bad news is: only very rarely the motor actually starts. Most of the time the motor doesn‘t start – despite the fact that the MTRS works every time.

Any ideas for me what to try next? Is it a mechanical or an electronics problem? How to find out? I‘m out of ideas … ?