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From: steveh@hpcvra.cv.hp.com.CV.HP.COM (Steve Harper)
Newsgroups: comp.sys.handhelds
Subject: Re: Other HP48 memory card sources, TETRAS
Message-ID: <25590078@hpcvra.cv.hp.com.CV.HP.COM>
Date: 16 Nov 90 17:43:26 GMT
References: <4550@tellab5.tellabs.com>
Organization: Hewlett-Packard Co., Corvallis, OR, USA
Lines: 20

The voltage which the 48 supplies to power the RAM cards
is generated by a power supply in the 48, so it does not
depend directly on the battery voltage level.  Putting
fresh batteries in your 48 will not make the so-called
"standard" RAM cards work any better when used in the
48.  If your 48 IC's happen to have been manufactured
such that the output Vdd is on the high side of the
spec AND the "standard" card you use happens to have
a cut-out voltage on the low side of its spec, then it
will work OK...  Otherwise, using these cards rather
than the HP cards is a rather risky and unreliable choice.
There is not a simple way to measure these values, nor
is a dealer likely to let you rummage through his stock
to find one you like... With mail order there's no choice
at all.  In all probability the worst that will happen is
calculator lock up and memory loss, but in theory at least
it is actually possible to damage your calculator if left
in the locked up state for a period of time.

Steve Harper