Path: utzoo!utgpu!tmsoft!dptcdc!dpmizar!swrinde!cs.utexas.edu!rutgers!mailrus!cornell!uw-beaver!ubc-cs!van-bc!skl From: skl@van-bc.UUCP (Samuel Lam) Newsgroups: comp.sys.ibm.pc Subject: Re: Exploding clock cards Summary: Maybe the card is supposed to use NiCad battery instead. Message-ID: <2012@van-bc.UUCP> Date: 9 Dec 88 08:47:14 GMT References: <16800395@clio> Organization: Balliffe Consulting, Vancouver, B.C., Canada Lines: 19 In article , greg@amdahl.uts.amdahl.com (Greg Bullough) wrote: > The card was replaced by a > very concerned dealer. I plugged in the new card, pulled the battery, > put a VOM across the clip, and turned on the computer. VOILA! > +5 VOLTS! Great design, huh? I cannot find a blocking diode, so I > assume it was left out of the design. > > Can anybody correct me if I'm wrong. It IS a no-no to put a positive > over-voltage across a lithium battery, isn't it?? Perhaps that particular card was designed to use NiCad battery (rechargable) instead of lithium battery (non-rechargable). The +5 volts that is used to recharge the NiCad while the computer is on will probably eventually blow up a lithium which found its way there. -- Samuel Lam {alberta,watmath,uw-beaver,cs.ubc.ca}!ubc-cs!van-bc!skl