Battery contact corrosion - why

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Battery contact corrosion - why

Postby EdinLA44 » Thu Nov 26, 2009 1:14 am

I've got a couple of HP-41s and I was curious about the battery contact corrosion that seems to plague some of them. I used a 41C all though my undergrad in the early 80s and it got used almost daily. It never sat unused in a drawer for very long. I changed batteries whenever I got the low battery warning. After about 3 years of use, it developed the greenish-white corrosion on just one of the 4 terminals. I used my pencil eraser to clean it up and kept using it. After two more months, corrosion had spread to all 4 terminals and eventually it failed to turn on and I gave it to a friend who wanted it. When I started my grad work in the early 90s, I bought a used -41CV and it never did corrode, whether it got used daily or sat in the drawer for weeks at a time. I sold that one after I finished my grad work. I bought the two I have now a couple of years ago and they spend most of the time in my desk drawer. No corrosion so far. So here's my question - did the corrosion problem occur due to a materials mis-application issue (using gold instead of another conductive metal) or was it contamination during manufacturing or some other cause? I'm curious as to why some seem to corrode and yet others don't.
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Re: Battery contact corrosion - why

Postby wfurlow » Tue Dec 01, 2009 4:20 pm

I don't know the chemistry behind it all, but I understand moisture is a big contributing factor. Was it in a very humid area? I don't know of any differences in the materials used in the connectors. Replacement connector foils are available from Diego Diaz.
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