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Francois Lanciault · 02-05-2015, 03:01 AM

A word of warning... sometime replacing the reader feed roller is not enough to get the reader to work adequately

I repaired my HP-67 card reader last weekend and replacing the gummy roller was easy and straightforward. But even with the new O-Rings, the card was pulled 2 to 3 times more slowly than usual. The "clutch" was the problem and I had to "fix" it with glue. Even after that the card was pulled at a speed that was still a bit too slow. I got Error 19 times out of 20. So I replaced the resistor with a trimer going from 4.4k to around 8k. Now everything works perfectly!

There are other potential problems that you may be faced with: bad capacitor, and badly adjusted nylon ball switches to name a few, but in my case I did not need to solve those issues.

Obviously as I never did this before I had to do a lot of ready of old MoHPC posts and a lot of experimentation. It took the whole weekend, but it was worth it. :-) Even my wife was impressed with a calculator that can read magnetic cards!!

François