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- Path: sparky!uunet!zaphod.mps.ohio-state.edu!cs.utexas.edu!gateway
- From: FELSON_ADJ@CCSUA.CTSTATEU.EDU
- Newsgroups: comp.sys.hp48
- Subject: Reversing batteries; was (none)
- Date: 21 Nov 1992 13:43:07 -0600
- Organization: UTexas Mail-to-News Gateway
- Lines: 31
- Sender: daemon@cs.utexas.edu
- Message-ID: <921121144303.238310ec@CCSUA.CTSTATEU.EDU>
- NNTP-Posting-Host: cs.utexas.edu
-
- Says: brianw@iat.holonet.net (Brian Walsh)
- Subject: Re: (none)
- fatri@turing.u-strasbg.FR (fatri -- licence info. --) writes:
- [stuff deleted]
- ! : I do so since I uses my HP very very often and for long periods and
- ! : I never had any problem until I put the batteries the wrong way round.
- ! : My calc died. (Bouuhhh !!!)
- ! : (I read this once in a book: if ON-[A]-[C] doesn't work, just put the
- ! : batteries the wrong way round for about half a second, this will make a
- ! : general reset ). I used to use this method because I didn't know about
- ! : the reset button at that time, and it never happend with ordinary
- ! : batteries.
- ! :
- ! : So if you use NiCd batteries, make sure you put them the right way on.
- !
- ! Reversing the batteries is a no-no on the 48. It was relatively safe to
- ! do with the 41 in case of a bad lockup, but virtually every machine since
- ! is not so tolerant. Use *only* the reset under the rubber foot in the
- ! event of a bad lockup. You will likely fry some circuitry by reversing
- ! batteries in the 48, at your own peril.
- !
-
- All it takes is a two cent diode to protect against voltage reversal. I haven't
- seen a piece of consumer electronics without this part since I started taking
- everything and anything apart 20 years ago. ( I am aware that disassembling my
- hp48 is beyond my skills. ) This diode will also make reversing the battery
- completely ineffective for discharging the power supply. If the reset doesn't
- work, leave the batteries out overnight. This should happen so often that one
- can't wait 8 hours for the power supply to discharge. ( I'm not known for my
- patience.... )
-
-