HP Forums

Hi Gang,

I've replaced a few deterioriated "gummy wheels" in the drives of HP-67's, one HP-97 and one in an external drive of an HP-41CX. In all cases of HP-67 replacement's I get a "error" message when feeding a card through after making the wheel fix. Ultimately, upon taking those units apart again and giggling things a bit, the problem has gone away. The giggle fix has always been a mystery to me. Now I'm working on an especially nice one and nothing I do seems to correct the problem. I've checked continuity sequencing for the "leaf contacts," and I don't see any wires that have come loose. Still when I feed the "Diagnostic Card" through, the "error" message presents.

1. Is there something I'm overlooking here?
2. Is there an alignment procedure for the leaf contacts/head?
3. Is there a manual or CD of alignment procedures for the 67/97 series available?

Any and all suggestions are welcomed..

Help please!

Mike DiGirolamo

Hi Mike:

First look at the magnetic head. You should read aprox 50 ohms in the orange-blue wires and also in the red-yellow. If that is not ok you need a replacement part.

Good luck

Jon

Jon,

Thanks for your post.

Is the stated resistance with the head in-line or removed?

Mike

PS Where does one find a replacement head, if needed :(

Jon,

I measure 50 - 58 ohms when head is disconnected.

Any other thoughts? Alignment?

Mike

Next step is the tantalum capacitor. You should replace the one at the top of the card reader´s circuit. 6 to 10uF will work fine. Take care with the polarity. If you send a photograph I will indicate which one must be replaced.

Good luck

Jon