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HP Forum Archive 12

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Is the '42S a battery hog?
Message #1 Posted by Dave Shaffer on 7 May 2003, 4:54 p.m.

The batteries just pooped out on my little-used 42S. It is one of the service units that were discovered two summers ago.

I haven't used it all that much, generally preferring my 41C , 41CX, and 11C for daily use. Maybe I am spoiled by the battery lifetimes on these latter units, but I am rather surprised that the 42S quit so soon. I doubt that it has even 20 hours on the battery set, whereas the older units get hundreds of hours on a set of batteries. (I use them regularly for MANY years, 5 to 10, before having to replace batteries.)

The little battery anunciator appeared above the two numerical display lines - for only a few minutes - before the batteries really died. This seems like a rather short warning interval!

I don't remember whether the dead batteries are ones that came with the calculator when I got it, or whether I had to put new ones in. If they are the originals, I can be somewhat forgiving - they probably sat around for several years. They are Panasonic LR44s - is Panasonic the HP OEM brand?

Might I have something turned on that shouldn't be - like the IR link? This calc didn't come with a manual. Could there be an internal short?

Also, it sits in a drawer most of the time. I don't think the ON button gets mashed in there, but it might. In any case, though, I would expect it to be turned off relatively quickly. What is the default turn-off time? I'd guess 5 or 10 minutes. (Can I change this?)

      
Re: Is the '42S a battery hog?
Message #2 Posted by David Smith on 7 May 2003, 5:07 p.m.,
in response to message #1 by Dave Shaffer

These machines draw just about as much power when OFF as when ON. Your batteries powered the machine for over a year... pretty good.

            
Re: Is the '42S a battery hog?
Message #3 Posted by Dave Shaffer on 7 May 2003, 5:17 p.m.,
in response to message #2 by David Smith

re: "These machines draw just about as much power when OFF as when ON."

Where does it go? Keeping the memory alive? If I don't have any programs stored, can I switch/take out the batteries to get a longer lifetime, or does something else bad happen?!

                  
Re: Is the '42S a battery hog?
Message #4 Posted by David Smith on 8 May 2003, 7:00 p.m.,
in response to message #3 by Dave Shaffer

The standby power goes into keeping the memory alive and part of the processor running. The "power" switch basically just turns off the display.

Yes, you can remove the batteries when the machine is not in use, but why bother. A guy on Ebay sells 10 batteries for $3.50. You might also break a battery spring, etc in the process (they were not designed for constant use as a true POWER switch).

      
Re: Is the '42S a battery hog?
Message #5 Posted by Paul Brogger on 7 May 2003, 5:40 p.m.,
in response to message #1 by Dave Shaffer

There's a flag concerned with IR ("PRINT") output that, if "on", causes a stream-of-machine-consciousness output of EVERYthing you do, with a concomitant increase in battery drain. You might want to check the PRINT settings . . .

I never use them (and so, no actual experience), but I believe you don't want the PRINT "PON" or "TRACE" modes set.

Also (I think), one of the three batteries being bad will mess up the whole group. Get some new Silver Oxide guys & pop 'em in there.

      
Re: Is the '42S a battery hog?
Message #6 Posted by Richard Garner on 7 May 2003, 5:50 p.m.,
in response to message #1 by Dave Shaffer

I use Silver Oxide batteries in mine and get about 2 to 3 years out of a set. If you use the plain alcoline batteries you will only get about 6 months.

      
Re: Is the '42S a battery hog?
Message #7 Posted by Randy Sloyer on 7 May 2003, 7:42 p.m.,
in response to message #1 by Dave Shaffer

Yes, the Panasonic LR44 was Hp's OEM battery supplied with the calculator. Just put in some new ones and you'll be good to go. Lucky guy. I still think we owe Johnny R. something for that HP parts find.

A good 42S consumes about 35-50 ua in use without I/R enabled. In standby, about 1 ua. It jumps to a power hogging 2 ma with a key down. So, theoretically speaking (and that's all it is) the 90mah LR44's should run a 42S for more than a year. I've used one daily for 12+ years and find the battery life to be between 1 to 3 years with alkaline cells. While silver oxides will last at least 2X, I've never found them at 1/2 the price, so I've never bothered.

I have seen 42S and 17Bii's that eat batteries in weeks. It is usually fuzz growing on the logic board somewhere caused by use outdoors and the resultant infiltration of undesirable elements. There is the rare flakey cpu as well for which there is no cure.


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