HP-65 card reader problems

[coitboy2000]

Hi all

After several weeks of trying to get me HP-65 to read cards, including reading may threads and trying many things, I have not succeeded so decide now would be a good time to post something here.

My HP-65 works fine apart from the card reader. When I first got it a few months back I replaced the gummy wheel and the reader was working generally ok. Not 100% but it would read and write. It then stopped pulling the cards through for some reason.

I have tried/observed the following. Forgive my basic electronics understanding.

- several diameter silicon tubes but decided to stick with the tubing I know works in my HP-41 card readers.
- checked the capacitors(2x22uf) and (1x3.3uf) across the motor.
- soldered new motor wires and checked ground etc
- If I power the calculator from my bench top power supply (4.5v) the calculator draws about 120-130ma, if I insert a card I can see the motor shaft shift a small amount and the current draw increases to 165-170ma. It won’t pull the card though. If I measure the current at the motor it is about 15ma. I don’t see any real voltage across the motor red and white wires when the card appears to be sensed and the amp draw increases ? Odd ?
- if I power the card motor directly it pulls the card fine. With 1.5v it draws about 170ma from memory and with 3v it draws about 210-220ma when it pulls the card through.

Not sure what else to try. The fact that it was working makes me feel like a component has failed?

Any comments appreciated

Richard