HP-67 Reads cards but does not write

[teenix]

With the switch leaf contacts, they should all be above the circuit board by the same distance. It is easy to try and adjust them and they become uneven. I'm not sure if the CRC chip is upset by this and causes R/W errors.

The short motor on time is due to the software. This usually happens when an error occurs, and the motor can speed up and run for a short time just as the card has passed through. As this seems to have occurred after you tried adjusting the switches, I'm wondering if this is due to the way the switches are adjusted, maybe it comes back to CRC timing.

The capacitor that seems to give card problems is marked on the diagram. If you decide to change it, then as John kindly mentioned, you may as well do them all.

The R/W head might need a cleaning also.

A couple of assembly tips,

When reassembling, make sure the keyboard assembly sits properly in the calculator before tightening the 6 screws. Sometimes the black plastic frame is not sitting properly (can rock back and forward a bit) and warps when tightened. This may affect the card reader.

Check the wiring at the top of the keyboard. These can fray if the disassembled calculator is moved too much and may limit battery current. My Classic Notes, page 44.

Lastly, be careful with the Power and Prgm/Run switches. The golden contacts can fall out causing a short on reassembly and when the battery is inserted can destroy the display Anode or Cathode drivers. I found this out the hard way.

cheers

Tony