HP Forum Archive 11

[ Return to Index | Top of Index ]

HP67 Card Reader Message #1 Posted by Howard on 18 Mar 2003, 4:09 a.m. The card reader on my HP67 gives the message "error" when it reads a card. It does not do this when it records a card. Does anybody know any possible cause this problem? Thank you.

Re: HP67 Card Reader Message #2 Posted by David Smith on 18 Mar 2003, 5:56 p.m., in response to message #1 by Howard First, I am assuming that the reader drive wheel has been rebuilt, and the heads, etc have been cleaned. If another machine can read the cards that you write, then the problem is almost certainly a bad small blue colored dipped tantalum capacitor. It is located near the top end of the card reader chip. This cap filters the power supply to the reader chip. It develops a high ESR and quits filtering properly.

Re: HP67 Card Reader Message #3 Posted by Howard on 19 Mar 2003, 5:53 a.m., in response to message #2 by David Smith Dave, I do not have another reader to test whether the cards I write can be read but I would be willing to try your solution. However my HP67 does not have a blue capacitor. It had a small (approx .25" long - .125" dia) tubular thingy with coloured stripes on it. I could replace it. I'll have to see what the size is. I think the coloured stripes are a code. Are the blue capacitors interchangeable with the one I have. Which, if any, is the better one? Thank you. Howard. PS I wonder if this is what is causing my problem with my card reader for the HP41. It just give "malfunction" on every attempt to read or write.

Re: HP67 Card Reader Message #4 Posted by David Smith on 19 Mar 2003, 6:17 p.m., in response to message #3 by Howard You have a very old reader circuit. The striped component you mention is a resistor that sets the motor speed. Don't mess with it. There are three tubular silver capacitors on these older boards. Two connect to the head winding circuitry and the other is the filter cap. I can't remember which is which. I do not know if the filter cap on these older readers is prone to the problem or not. I replace that little blue devil on any reader that I rebuild. I think they will all go bad someday... just like the rubber roller.

Re: HP67 Card Reader Message #5 Posted by Howard on 20 Mar 2003, 4:37 p.m., in response to message #4 by David Smith So do you think I should replace all three of those capacitors?

Re: HP67 Card Reader Message #6 Posted by David Smith on 20 Mar 2003, 5:50 p.m., in response to message #5 by Howard I would try to find the one on the power supply first. But replacing all three would be almost as easy.

Re: HP67 Card Reader Message #7 Posted by Howard on 26 Mar 2003, 8:27 a.m., in response to message #6 by David Smith David, I don't have much of a clue about electronics. The three capacitors are marked 4v and 15k and two 4v 22k. Radio Shack and other places I made enquiries at looked at me like I was stupid when I asked for these. They are all measured in micro and pico farrads now. Are they interchangeable. Can you give me a clue. What should I ask for? Thank you. Howard.

Re: HP67 Card Reader Message #8 Posted by Bengt Walerud on 19 Mar 2003, 4:24 a.m., in response to message #1 by Howard Thanks for the reply. Don't feel too comfortable to take my HP 65 apart but will try it out. Read your posting regarding batteries. I would like to preserve the calculator in original condition i.e use the battery pack and find Ni-Cd batteries that fit in the pack. Any ideas? I live in Sweden.

Sorry! Message #9 Posted by Bengt Walerud on 19 Mar 2003, 4:27 a.m., in response to message #8 by Bengt Walerud Ignore last message I posted in wrong thread

[ Return to Index | Top of Index ]

Go back to the main exhibit hall