Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!sun-barr!decwrl!ucbvax!hplabs!hp-sdd!hp-pcd!hpcvra!prestonb
From: prestonb@hpcvra.CV.HP.COM (Preston Brown)
Newsgroups: comp.sys.handhelds
Subject: Re: Power consumption of the HP-28s.
Message-ID: <17980007@hpcvra.CV.HP.COM>
Date: 5 Dec 89 01:53:27 GMT
References: <2359@gmu90x.gmu.edu>
Organization: Hewlett-Packard Co., Corvallis, OR, USA
Lines: 18


>     A while back someone posted an undocumented storage mode for the
>calculator; if you press on-enter-backspace at the same time, the
>calculator will beep and shut off. Even the internal clock stops!
>When the calculator is normally off (NOT in storage mode) it draws
>13.5  uAMPS. In "storage" mode, it draws 106.2 uAMPS!! This is 7.8 times
>the current drain! So what is "storage" mode really doing?

Your right, it does draw higher current;  its basically a bug in the
hardware.  The storage mode or "Coma" mode was designed for factory
checking of the leakage currents of the ICs (a very good measure of
IC reliability)  and as a mode the calculators could be shipped in to
increase the shelf life of the batteries.  The only problem is that
a pin on one of the ICs is left in a high current state.  It shouldn't
cause any problems with your calculator only you can't use it as a low
current state.

Preston Brown