HP Forum Archive 05

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How to clean HP41's battery contacts Message #1 Posted by Marx Pio(Brasil) on 17 Jan 2001, 6:28 a.m. There is one battery contact that is showing signs og corrosion. How can I clean without damage it? Finaly I got my first fullnut 41CV. Lets party!

Re: How to clean HP41's battery contacts Message #2 Posted by Erik Wahlin on 17 Jan 2001, 8:23 p.m., in response to message #1 by Marx Pio(Brasil) I know of no better method except to cautiously scrape off the corrosion. Make sure that you don't scrape off the gold plating. If you do, you can try using a conductive epoxy on the damaged area. This has worked for several of my rebuilds.

Re: How to clean HP41's battery contacts Message #3 Posted by Katie on 17 Jan 2001, 10:04 p.m., in response to message #2 by Erik Wahlin Erik, I've tried your conductive epoxy method for battery contact rebuilding. All the contacts in one of my 41's had completely disintegrated. The conductive epoxy worked sort of intermittently until I coated the epoxy with a conductive coating from a "circuitworks" pen, now it works great! -Katie

Re: How to clean HP41's battery contacts Message #4 Posted by Erik Wahlin on 17 Jan 2001, 11:12 p.m., in response to message #3 by Katie Hi Katie, I have found that you have to mix the epoxy just right to get good results. I have never had any problems with one particular batch I made. I had repaired about three contacts with it and they still seem to be ok. My first attempt I must not have had the proper ratio (50:50) or blended it well, because the batch was not very conductive.

Re: How to clean HP41's battery contacts Message #5 Posted by Marx Pio(Brasil) on 18 Jan 2001, 8:05 p.m., in response to message #4 by Erik Wahlin Wahlin, Can I use a silver based condutive ink on the contacts? I didn't found the epoxi you mentioned. Thanks,

Re: How to clean HP41's battery contacts Message #6 Posted by Erik Wahlin on 19 Jan 2001, 12:07 a.m., in response to message #5 by Marx Pio(Brasil) Hi I have not used that kind of conductive ink before. I suppose it would work if it has good conductivity and is reasonably durable.

Re: How to clean HP41's battery contacts Message #7 Posted by David Fenyes on 5 Feb 2001, 12:55 a.m., in response to message #1 by Marx Pio(Brasil) The battery contacts in mine seem fine, so I haven't had to try anything yet, but I've used dilute phosphoric acid (followed by distilled water, followed by alcohol) to clean copper surfaces in the past. Alternatively, It looks like you could cut and place copper electrical tape over the contacts, and solder to the PCB. Regards, David.

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