Hp-41C card reader - dead

[do2]

I bought a used card reader recently, and as it happens I managed to repair it just today!

It had the usual problems. At first, I thought I can get away with replacing the deteriorated rubber on the capstan, but this resulted in checksum errors and malfunctions. In the end I had to superglue the silicon tubing (I went with this solution) and the tiny aluminum sleeve on the worm wheel and motor shaft. Problem solved

I am skeptical that more elaborate solutions with thin cable insulations to mount the worm wheel would provide any significant dampening effect to justify the efforts. But I can definitely report that a rock solid mounting of the o-rings/tubing to the capstan and of the worm gear to motor shaft is mission critical for the card reader to work.

Best,
odo