HP Forum Archive 17

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Hp-67 Card reader Message #1 Posted by Tim on 27 May 2007, 6:06 p.m. I have done a repair on the card reader. The calculator pulls the card through the calculator now. However it keep telling me error. Any suggestions?

Re: Hp-67 Card reader Message #2 Posted by Randy on 27 May 2007, 6:45 p.m., in response to message #1 by Tim Reading or writing failures?

Re: Hp-67 Card reader Message #3 Posted by Dan W on 27 May 2007, 10:45 p.m., in response to message #1 by Tim More or less what I do, in this order: Make sure you have a known good card. Helps to have a working 67. Double check all 5 of the wires from the r/w head. These can come loose easily and it's easy to miss. Also check all the other wires attached to the PCB. Be sure the PCB is correctly connected to the mainboard. If that fails, open it up and check that all 4 tiny balls and the roller are in place, and also the two metal leaf springs are in place. Try writing instead of reading to isolate the problem. -- Dan

Re: Hp-67 Card reader Message #4 Posted by Tim on 27 May 2007, 11:03 p.m., in response to message #3 by Dan W It fails on reading only.

Re: Hp-67 Card reader Message #5 Posted by David Smith on 30 May 2007, 10:53 a.m., in response to message #4 by Tim A card reader that writes but does not read is almost always a bad tantalum filter capacitor (usually a small blue dipped tantalum) on the card read power line.

Re: Hp-67 Card reader Message #6 Posted by Tony Duell on 29 May 2007, 4:30 a.m., in response to message #3 by Dan W Do you have another 67, 97 or 41 (that is, something that can read a 67 card)? If so, try writing a card on the faulty machine and see if you can read it on the good one. If you can't, check the head wiring, and check the head windings for continuity. There are 2 windings, IIRC, one has red and yellow wires, the other blue and orange wires (but I would have to check that in the schematics). If one winding is open, you can neither read nor write a card, and you're looking for a new head assembly (yes, I have had them fail). The other thing to check are the decoupling capacitors on the various power lines. If one is defective, you get noise in the read amplifier from the motor. This will stop the machine from reading (although it will normally write OK).

Re: Hp-67 Card reader Message #7 Posted by Tim on 30 May 2007, 8:18 p.m., in response to message #6 by Tony Duell What is the value of the tantalum? Does anyone have the schematic?

Re: Hp-67 Card reader Message #8 Posted by Randy on 30 May 2007, 8:55 p.m., in response to message #7 by Tim It's the only 6.8uf on the reader board. Schematics of the 67 and others are available from http://www.hpcc.org/cdroms/ and are well worth the $. Thank you Tony...

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