I purchased an HP-67 off ebay. When I received it, the card reader wasn't working. After repairing the drive wheel, it worked mechanically, but generated an error message when reading or writing cards. I replaced the capacitors that are known to cause reader problems. It still gave error messages. I measured the head continuity; one side read open, so the head was bad. I removed the head and sent it to JRF Magnetic Sciences. John didn't have an exact match, so he sent me the best match he had. I installed the head and the calculator is now working perfectly. I have attached before and after pictures. I apologize for the poor workmanship, but I had to use leftovers from my parts bins, so I didn't even have the correct wiring: wrong colours and low-temp insulation. I may order the correct wiring and redo everything to clean up the workmanship, but I'm so happy to have it working, I may put that off for a while.
Before
After
Edited: 10 May 2010, 2:13 p.m.