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HP Forum Archive 14

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HP-65 card reader only reads cards
Message #1 Posted by Michael Reinold on 24 Feb 2004, 10:55 a.m.

Last week, I've got my second HP-65. Because it suffers from the gummy-wheel-problem, I replaced the wheel with o-rings. Now the machine reads every card from my first HP-65 with a high grade of reliability. There is only one flaw: in write-mode it doesn't write anything to the card. It leaves the contents of the card untouched. The card is OK, the edge is not cut.

Is there anybody out there who can give me a tip?

Michael

      
Re: HP-65 card reader only reads cards
Message #2 Posted by David Smith on 24 Feb 2004, 6:06 p.m.,
in response to message #1 by Michael Reinold

Most likely is a misadjusted write protect switch. These are the little gold fingers on the back of the reader assembly. When a card is inserted, the little nylon ball presses the finger against a pad on the back of the keyboard. There are three operation switches (MOTOR, WRITE PROTECT, and HEAD ENABLE). They should close and open in sequence as the card makes its way through the machine.

The adjustments can be quite tricky as the fingers only move a few thousanths of an inch. You need to trace the contacts to the keyboard connector pins and see if any switches are stuck open or closed. Usually you can adjust them with those tiny screws on each reader finger. Sometimes you must bend the fingers (woe unto you if you need to do this...)

      
Re: HP-65 card reader only reads cards
Message #3 Posted by quemazon on 1 Mar 2004, 11:36 a.m.,
in response to message #1 by Michael Reinold

It could be that you have knocked a wire loose. I had this problem when fixing a 67. Check to see if anything needs to be resoldered.


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