HP Forum Archive 20

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HP-41 Card Reader Error Message #1 Posted by aj04062 on 22 Sept 2011, 11:36 p.m. I recently rebuilt my Card Reader. The card runs smoothly, but I consistently get Card Err or Malfunction or Checksum Error. Some threads point to the 2 contacts. I swapped and checked to make sure they are flat. I applied contact cleaner as well. I tried a different calculator, but that didn't work. Suggestions?

Re: HP-41 Card Reader Error Message #2 Posted by John Robinson on 23 Sept 2011, 5:33 p.m., in response to message #1 by aj04062 Hi Adam, If you get inconsistent results, then I'd say there is hope. And I presume you had never seen such errors before the rebuild / My guess is that you need to spend more time adjusting the roller pressure. Is the motor struggling ? Cheers, John

Re: HP-41 Card Reader Error Message #3 Posted by aj04062 on 24 Sept 2011, 9:41 p.m., in response to message #2 by John Robinson I swapped the rebuilt drive assy with another card reader I had. This assembly works great. So, I presume from browsing older posts, the cause of these errors/malfunctions could be the capacitor adjacent to the sense amplifier chip. I will try this next after I rebuild another drive unit.

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