Path: utzoo!mnetor!uunet!lll-winken!lll-lcc!ames!ucsd!sdcsvax!ucsdhub!hp-sdd!hplabs!hp-pcd!hpcvra!billw
From: billw@hpcvra.HP.COM (Bill Wickes)
Newsgroups: comp.sys.hp
Subject: Re: Memory lost on HP28C
Message-ID: <5040006@hpcvra.HP.COM>
Date: 24 Feb 88 17:37:49 GMT
References: <1770@phoenix.Princeton.EDU>
Organization: Hewlett-Packard Co., Corvallis, OR, USA
Lines: 16

The memory lost problem has plagued the 28C throughout its product life.
The problem appears to arise from corrosion (microscopic, not
great dripping rust blobs) of the battery contacts.  All 28's are
now shipped with Kodak batteries; their gold contacts seem to substantially
alleviate the problem.  Other things you can try for preventative
medicine:

*Clean the battery contacts every week or so with a pencil eraser.

*Insert a thin wedge of foam tape along one corner of the battery
compartment to keep the batteries from rattling in the case.

If these measures don't improve matters, you may simply have a bad
unit--send it in for warranty service.  Also, as for any other
CMOS calculator, be careful of static electricity.  The 28
can survive shocks on the order of 15KV, but it's possible to
exceed this in particularly dry conditions