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HP Forum Archive 19

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HP 41CV card reader
Message #1 Posted by John Bjornholt on 4 Feb 2009, 11:54 a.m.

Does anyone have any technical info on the HP41CV card reader, such as schematics, block diagrams, trouble-shooting procedures, etc? I recently sucessfully repaired the drive wheel on mine, but now I get a "malfunction" display when it tries to read a card. I have an o-scope and other necessary test equipment to check for waveforms, voltages, etc.

      
Re: HP 41CV card reader
Message #2 Posted by PeterP on 4 Feb 2009, 12:01 p.m.,
in response to message #1 by John Bjornholt

IIRC, TOS has the Card Reader Repair Manual from HP. Also a Google on 'repair card reader site:www.hpmuseum.org' or something along these lines will bring up many threads with potentially useful information. There recently was one where a defect cap was the source of reading problems.

HTH

Cheers

Peter

Edited: 4 Feb 2009, 12:03 p.m.

            
Re: HP 41CV card reader
Message #3 Posted by Roy Welch on 4 Feb 2009, 8:27 p.m.,
in response to message #2 by PeterP

Peter, what is the IIRC and TOS? I also need to get the LED part I discussed with you. Maybe a schematic or parts list is available.

Roy

                  
Re: HP 41CV card reader
Message #4 Posted by Jeff O. on 5 Feb 2009, 7:28 a.m.,
in response to message #3 by Roy Welch

IIRC - If I Recall Correctly

TOS - That Other Site. Another HP related web site. It is a long story, but suffice it to say that out of respect to the owner of this web site, links to and direct mention of the name of that other site is not done.

                        
Re: HP 41CV card reader
Message #5 Posted by Roy Welch on 5 Feb 2009, 10:32 a.m.,
in response to message #4 by Jeff O.

OK, thanks. The LED is an IR type I'm told. The lens of the LED was shattered so I can't see the flat side showing the polarity indication. That's why I need the schematic.

Roy

      
Re: HP 41CV card reader
Message #6 Posted by Carl Vanden Bulcke on 9 Feb 2009, 3:11 p.m.,
in response to message #1 by John Bjornholt

Hi, I have a similar problem with the drive wheel where the friction wheel seems to have "dissolved". Could you let me know how this could be replaced/repaired? Are parts still available from hp? Thanks for your help! Carl Vanden Bulcke _ Belgium

            
Re: HP 41CV card reader
Message #7 Posted by Michael de Estrada on 9 Feb 2009, 3:48 p.m.,
in response to message #6 by Carl Vanden Bulcke

This is commonly referred to as the "gummy wheel", and it can be repaired either with plastic tubing or O-rings. There are several articles under the "card reader repair" heading in the articles section of this forum. You can find suitable O-rings on ebay, and I have had success with this method on several card readers. Parts are not available from HP. Also, I don't know if the HP-41 series card reader has a motor clutch similar to the HP-65 or HP-67, but if it does, it may also need repair.

                  
Re: HP 41CV card reader
Message #8 Posted by Ignazio Cara (Italy) on 10 Feb 2009, 2:17 a.m.,
in response to message #7 by Michael de Estrada

The coupling between motor shaft-worm gear is surely the same of 65, 67 and 97.

regards

Ignazio


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