The Museum of HP Calculators

HP Forum Archive 08

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dead 41CV
Message #1 Posted by J Tiers on 21 Aug 2002, 1:25 p.m.

This machine has worked since 1978 or so, and has indeed been back to HP (who seem to have hams for hands).

Anyway, it was working as I was doing calculations, then quit in a few seconds between the time I set it down and picked it up again, possibly 4 sec or so. As I wasn't watching, I don't know what exactly it did.

No display or response.

It was then disassembled, the broken posts etc reinforced and glued, but still no response. Contact appears to be made to all the pieces.

It has the extra board with CPU etc, and does not appear to have any opens or etc on the display.

Any OTHER ideas? Symptoms (and life) are noticeably lacking!

      
No, batteries were NOT the problem
Message #2 Posted by J Tiers on 21 Aug 2002, 10:21 p.m.,
in response to message #1 by J Tiers

That caught me once many years ago.

            
And, yes I have already gone thru the archives
Message #3 Posted by J Tiers on 22 Aug 2002, 8:36 a.m.,
in response to message #2 by J Tiers

so I am not just popping up here to ask a dumb question with no research.

There used to be a bunch of folks commenting on fixing 41C units, they must have all left by now.....................

      
Re: dead 41CV
Message #4 Posted by Dan M on 22 Aug 2002, 9:04 a.m.,
in response to message #1 by J Tiers

I have had terrible luck with the style of "zebra strips" that are long white rectangles with the conductor going up through the middle of them. The "zebra strips" are the things that connect the logic board with the keyboard. If the connection is no good, then the calculator won't work.

Do you have these kind of "zebra strips," or the other kind where the conductor wraps around the outside of a squishy tube? In either case, as I'm sure you know, you should "un-squish" the squishy part in the hopes to make better contact between the boards. I have not been able to get the white rectangle strips un-squished enough to work reliably once they stop working. Maybe others have had better luck.

This is one way (bad zebra strip connection) that a 41 calculator with all known good parts won't work at all.

Good luck, and sorry for the lack of technical terms.

Dan

            
Re: dead 41CV
Message #5 Posted by thibaut.be on 22 Aug 2002, 9:41 a.m.,
in response to message #4 by Dan M

Indeed, I've ressucited several 41 by just stretching the zebra strips...

            
It is a "fullnut", so I have all the
Message #6 Posted by JTiers on 22 Aug 2002, 12:42 p.m.,
in response to message #4 by Dan M

strips. I think Fullnut has the CPU board, right?

The strips seem to be making contact, and the failure mode was a quick total failure. No flakyness, no indication of problems, worked and suddenly stopped.

Is the info on the CD's useful? I looked at what is available, and didn't seem to find specific 41 info. Maybe I didn't realize what was meant.....

                  
Re: It is a "fullnut", so I have all the
Message #7 Posted by Ellis Easley on 22 Aug 2002, 1:39 p.m.,
in response to message #6 by JTiers

There is a 41C service manual on the Museum CD-ROMs.

                        
Yep, ordered it thanks NM
Message #8 Posted by J Tiers on 23 Aug 2002, 8:44 a.m.,
in response to message #7 by Ellis Easley

nm


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