The Museum of HP Calculators

HP Forum Archive 16

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Minor Calcuator Repair/HP 41CV/HP 12C
Message #1 Posted by Kevin on 25 Aug 2006, 10:11 a.m.

I have an old HP 41CV that I have had since college (vintage 1984). When I checked recently, there was a fair amount of corrosion on the contacts at both ends of one of the batteries. Strangely, I don't see anything leaking from the battery. I can't recall the last time I changed batteries - it might have been 6 or 8 years ago. Everything still works.

What is the best way to clean the contacts? Alcohol and a cotton swab?

Also, I've picked up an older made in the USA vintage 12C. I've not received it yet - but from the pictures it looks like 1 of the 4 rubber feet are missing. I'm not overly picky about these things. Any chance I could find something reasonable at a hardware store to replace these feet? I'm thinking I might replace the 2 on that side so that the thing rests firmly.

Finally, what's the best place to get replacement batteries for the HP41CV and 12C. I think I went to Radio Shack last time - they seem to be a bit expensive. Can you get these batteries from Amazon or other online places?

Thanks,

Kevin

      
Re: Minor Calcuator Repair/HP 41CV/HP 12C
Message #2 Posted by Jeff O. on 25 Aug 2006, 4:02 p.m.,
in response to message #1 by Kevin

Quote:
What is the best way to clean the contacts? Alcohol and a cotton swab?
Is there corrosion on the contact(s) in the calculator? Assuming the answer is yes and it's the typical blue-green looking crud, I'm not sure that alcohol is the best cleaner. Good old water will probably do the trick, using a damp soft cloth so as not to get any free liquid loose in the calculator. When you get as much crud as possible off, try to polish the contact(s) with a pencil eraser (the soft white kind if available). These contacts are very thin, so anything more aggressive (e.g. sandpaper) risks damage that you don't want to have to deal with. The cleaning process would likely be easier if you disassembled the calculator. The battery contact-I/O block comes out rather easily once you remove the back. However, the screw posts on the 41 series are notoriously weak, so remove and reinstall the screws with extreme care. Maybe best to disassemble only if the first cleaning method doesn't produce adequate results.
Quote:
I've picked up an older made in the USA vintage 12C...Any chance I could find something reasonable at a hardware store to replace these feet?
Well itís not a hardware store and youíll have to buy 10 lifetime supplies of foot-replacement material, but part no. 8635K26 from this supplier was identified somewhere/sometime as a good material for this purpose.
Quote:
Finally, what's the best place to get replacement batteries...
You might take a look here and here. I have purchased from the Battery Station, service was fine. I donít know if I ever bought from the other source.

The above advice is thought to be reasonable, but follow at your own risk. Good luck with your repairs.
            
Re: Minor Calcuator Repair/HP 41CV/HP 12C
Message #3 Posted by Kevin on 25 Aug 2006, 6:01 p.m.,
in response to message #2 by Jeff O.

Thanks!

                  
Re: Minor Calcuator Repair/HP 41CV/HP 12C
Message #4 Posted by Doug on 26 Aug 2006, 8:04 p.m.,
in response to message #3 by Kevin

Kevin, Circuit City sells Coppertop N cells for $2 a pair.

                        
Re: Minor Calcuator Repair/HP 41CV/HP 12C
Message #5 Posted by Kevin on 26 Aug 2006, 11:51 p.m.,
in response to message #4 by Doug

Thanks - yea - they're not as rare as I thought. That would save shipping from an internet store.


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