HP-65 card reader repair - can't write card, but can read

[jay]

EDIT: turns out that it can read cards, but not write - see http://www.hpmuseum.org/forum/thread-698...l#pid64043

Hello,

I'm in the process of repairing an HP-65's card reader. I've replaced the gummy wheel and the motor to worm coupler. Thanks to Paul Berger, I have some cards I can use to test it.

The cards appear to be driven through properly when I insert them. I enter a program in W/PRGM mode, insert a card to write the program to it. The screen blanks while the card goes through the machine, and the calculator displays a steady "00 00". I switch the mode to RUN, and put the card in to read the program back. The screen blanks while the card is being read, then I get a flashing display, which I understand to mean that it couldn't read the card.

Any suggestions on what to check next?

Thanks again to Paul for sending me those cards!