HP-65 card reader problems

[teenix]

(02-16-2020 11:09 AM)AndiGer Wrote:  Reading the thread I am thinking as it is not mentioned:
Did you check the motor switch closing when inserting a card? Carefully cleaned the contact?
It seems not so convenient to measure as on the 97 card reader with it's test points but should be possible ...
Andi

Very good point. I mentioned this in previous post, but wasn't pursuing it earlier because of the mentioned symptom which I took to indicate that the motor was trying to move.

> The drive shaft does move axially but won't pull the card and I only measure
> some 50mv across the motor terminals

To be safe, remove the battery and CPU board, and with an ohm meter just measure from the keyboard pins, the pin I mentioned to GND. It should short when the card is inserted.

And my apologies, the CPU board pin #9 name is MTRS not HDS.
GND is pin #14.

cheers

Tony