From: John H Meyers on 17 Oct 2006 17:22
Perusal of the HP50G User's Manual, HP50G User's Guide,
and 49G+/48Gii Advanced User's Reference Manual
tells me to replace "the batteries"
when a "Low Battery" warning appears,
but not to replace the main batteries and backup battery
at the same time; I can't seem to find any suggestions
about the expected life of the backup battery,
with or without main batteries in place,
nor any suggested replacement interval.
I wonder whether Arturo might recommend
tossing the calculator into the air once every year,
to see whether it lands "heads" or "tails" --
but I'm not sure which way would mean
to change the backup battery this time,
vs. which would mean to wait until next year :)
I was once at a radio station which similarly
found it not worth bothering to keep track
of the expected lifetimes of the batteries
in all of its condenser microphones,
so about every six months (microphone batteries
evidently run down much faster than calc batteries)
they just declare "battery changing day,"
hunt down every microphone in the station,
and change them all -- apparently the smaller discards
then go into parking meters, if I recall correctly ;-)
From: Avatar_e on 17 Oct 2006 17:38
> It's too bad the ARM-based calcs don't use the same coin cell
> as the 48-series RAM cards, for then the answer might be
> to transfer the cell to a 48-series RAM card, plug the RAM card
> into a 48-series calc and turn it on, and the good old HP48
> would then tell you whether the cell needed replacement :)
> [r->] [OFF]
A cheap chinese multimeter can be useful, but what level is "bad" for
the 3V cell battery?
From: John H Meyers on 17 Oct 2006 18:40
On Tue, 17 Oct 2006 15:35:02 -0500, bokubob wrote:
> Page 26-9 of the HP 49G+ User's guide* (edition 4, p/n F2228-90006):
> Backup battery
> A CR2032 back up battery is included in the calculator to provide power
> backup to volatile memory when changing the main batteries.It is recommended that you replace this battery every 5 years.
> A screen message will indicate when this battery needs replacement.
> * Available for download at:
Well, it turns out that there's something like that in the 50G+
User's Guide also, page 26-13 in F2229AA-90006;
of course the nearly identical "Batteries" sections
in the very *front* of both User's Guide and User's Manual
neglect to say anything about replacing the backup battery,
nor even "see page xx-yy for more info"; the Guide's Index
has no entry for either "Batter[y/ies]" or "Backup,"
and the Manual has no Index at all -- this is evidently
like one of those "tricks" you get on exams, to make sure
that you read the entire manual before touching the calc :)
A message will appear when the backup battery needs
replacing? How come there was no message
when I *removed* my backup battery last year?
Who would like to put this to the test again now,
"in the interest of science"?
About the sometimes crucial importance
of clear (and correct) instructions:
In November 2000, 19,000 people in a single county,
when faced with a double-wide ballot page designed for
that county alone, saying "Vote for any TWO" right at the top,
punched TWO holes in their USA Presidential ballots
(they thought that this meant to punch holes for
*both* President and Vice-President together,
as many subsequent "exit interviews" ascertained);
the great majority of those *pairs* of punched holes
were as close to Gore & Lieberman's names as they could get,
but what the Elections commission said was that they had
voted for both the Gore ticket and the Buchanan ticket
(a contradictory and invalid combination),
and were declared disqualified, which tilted the balance
by more than 10,000 votes in Florida (the later pursuit of
a few hundred "hanging chad" was a desperate effort to reverse
the real mistake, which was beyond fixing), which changed
the "winner takes all" electoral votes of that entire state,
which made Bush president, instead of Gore.
Although a set of calculator manuals (and on-calc functions)
isn't likely to affect the world as much as that extraordinary
"Human Factors" gaffe which changed recent history,
this field of relating to real people (and how their minds work)
is always of recurring significance in modern life,
either guiding people automatically into right action
or misleading them (or just wasting their time),
as can be seen even from your calculator and its manuals.
"Human Factors" at random:
http://www.humanfactors.com [software design consultants]
http://www.baddesigns.com [a "comedy of errors"]
http://www.wepsite.de/driving_instructor.htm [classic Bob Newhart]
Best wishes from http://www.mum.edu
From: bokubob on 17 Oct 2006 20:29
John H Meyers wrote:
> the Guide's Index
> has no entry for either "Batter[y/ies]" or "Backup,"
> and the Manual has no Index at all --
It's in the table of contents under Managing Memory, even in bold.
One of the nice things about HP providing the manuals in nice PDF files
is that they're searchable. It took me less than two minutes to find
the answer (fink file, open viewer, type "battery" click, click, done).
Anyway, now you know, so you can mark your calendar.
From: Veli-Pekka Nousiainen on 18 Oct 2006 09:06
John H Meyers wrote:
> In November 2000, 19,000 people in a single county,
> when faced with a double-wide ballot page designed for
> that county alone, saying "Vote for any TWO" right at the top,
> punched TWO holes in their USA Presidential ballots
> (they thought that this meant to punch holes for
> *both* President and Vice-President together,
> as many subsequent "exit interviews" ascertained);
> the great majority of those *pairs* of punched holes
> were as close to Gore & Lieberman's names as they could get,
> but what the Elections commission said was that they had
> voted for both the Gore ticket and the Buchanan ticket
> (a contradictory and invalid combination),
> and were declared disqualified, which tilted the balance
> by more than 10,000 votes in Florida (the later pursuit of
> a few hundred "hanging chad" was a desperate effort to reverse
> the real mistake, which was beyond fixing), which changed
> the "winner takes all" electoral votes of that entire state,
> which made Bush president, instead of Gore.
You mean that Bush voters made no mistake whatsoever
or that there were substantially more Gore voters in error?
Perhaps HP users vote Bush (Retarded Politics Nothingness)
and TI users vote ALG(ore)