HP-97 card reader repair
#1

I have a HP-97 that is in good shape and works well except for the card reader. I went through all of the repair steps provided by Steve L. at the HP Museum, including testing the feed of a card using a classic battery pack. That all went well. But when I reassembled the unit everything worked except for the card reader. It appears to not detect the card insertion or does not have power to the reader.

Anyone know what might be wrong? I know the motor and my new pinch wheel work. Could it be the ribbon cable or is there a microswitch in the reader which detects card insertion?

#2

Such "microswitch", at least on the handhelds, is made with a long and thin, elastic, gold-plated "leaf" that arches when pushed on one end, so making contact with the printed circuit board. Now, what makes the leaf bend ? A small plastic piece (sort of a cylinder, no more than 2 mm in diameter), that protrudes on the card track, and that is pushed by the card. The cylinder, in turn, pushes the "leaf" and, forcing it to arch and close the contacts, signalling the card insertion. Please disregard any idiomatic mistake, I hope this may help you.

#3

As Andres says there are microswitches (leaf contacts) but if you didnt touch them they are probably OK. Chances are that your ribbon cable has not been inserted correctly or the conductor has flaked from the backing.

#4

Thanks for the help!

#5

Thanks for the advice. I will look more carefully at the ribbon cable because I was very careful with the gold leaf so it should not be that. Thanks again!



Possibly Related Threads…
Thread Author Replies Views Last Post
  Reasonable price for a 41C, Quad Mem, Time, Navigation and Card reader module? Eelco Rouw 10 4,633 12-12-2013, 01:52 AM
Last Post: Eelco Rouw
  hp-67 card reader problem. Marcel Samek 5 3,154 12-09-2013, 09:09 PM
Last Post: Paul Berger (Canada)
  HP-97 card reader pinch roller axle davorin 2 1,578 09-15-2013, 08:47 AM
Last Post: aj04062
  HP-97 Card Reader davorin 3 1,859 09-13-2013, 04:21 PM
Last Post: Stephan Matthys
  HP-67 Card Reader Repair Question aj04062 1 1,483 08-08-2013, 11:15 AM
Last Post: Randy
  Hp-67 card reader: tantalum capacitor identification Ignacio Sánchez 8 3,178 06-02-2013, 07:26 PM
Last Post: aj04062
  Testing card reader motor for 65 Michae Altmann 2 1,599 03-17-2013, 09:24 PM
Last Post: Randy
  Repaired HP-97 card reader doesn't show any signs of life jbssm 6 2,602 02-17-2013, 03:15 AM
Last Post: Alberto Fenini
  HP 65 card reader problem H Fischer 3 1,494 11-24-2012, 12:11 PM
Last Post: H Fischer
  41CL and Card reader Prabhu Bhooplapur 3 1,556 10-18-2012, 07:40 AM
Last Post: Ángel Martin

Forum Jump: