HP Forum Archive 16

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bad HP41CX? Message #1 Posted by Gonzalo Fernandez (Spain) on 9 Dec 2006, 12:44 p.m. I have an HP41CX halfnut that when I put a magnetic card in a card reader, the motor of the card reader doesnīt turn on. Doing CAT 2 shows card reader present, so at least some power is available in slot 4 of the HP41CX. I have put a math module in slot 4 and shows all functions, the module works well. I have checked the card reader in an HP41CV and works perfectly. Maybe this problem should be a bad capacitor of the HP41CX? thanks

Re: bad HP41CX? [card reader] Message #2 Posted by Karl Schneider on 9 Dec 2006, 2:28 p.m., in response to message #1 by Gonzalo Fernandez (Spain) Hello, Gonzalo -- One basic thing to check is voltage on each "N" cell (or simply use the battery set from your 41CV. Running the motor to read or write a card requires a certain amount of power that is drawn from the HP-41, and that capability is probably the first to be lost when the battery becomes discharged. (Clock functions are next to go...) -- KS

Re: bad HP41CX? [card reader] Message #3 Posted by Gonzalo Fernandez (Spain) on 9 Dec 2006, 7:15 p.m., in response to message #2 by Karl Schneider Hello: I have tested it with a new set of batteries. It seems it doesnīt arrive enough power in the slot 4 toward the card reader gonzalo

Re: bad HP41CX? Message #4 Posted by Hal Bitton on 9 Dec 2006, 7:46 p.m., in response to message #1 by Gonzalo Fernandez (Spain) I think there's a hot shoe (unswitched) that's unique to port 4 to run the card reader. It may be bad in your machine. Best regards, Hal

Re: bad HP41CX? Message #5 Posted by Gonzalo Fernandez (Spain) on 10 Dec 2006, 5:32 a.m., in response to message #4 by Hal Bitton Which piece is unique to port 4 of the 41CX? I have the schematic of the 41CX and donīt see any difference between port 4 and ports 1-3.

Re: bad HP41CX? Message #6 Posted by Randy on 10 Dec 2006, 10:50 a.m., in response to message #5 by Gonzalo Fernandez (Spain) Port 4 has the lines B3 and B4 connected together, it is the only port with that configuration. It is shown on the schematics and is obvious if you examine the port I/O block. I would remove the I/O block and look for battery corrosion, the most likely cause of your problem. Edited: 10 Dec 2006, 10:51 a.m.

Re: bad HP41CX? Message #7 Posted by Jon on 12 Dec 2006, 2:06 p.m., in response to message #6 by Randy If you clean the contacts of port 4 with isopropilic alcohol you will probably fix it. Good luck Jon

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