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HP 12C - refresh batteries or not?
11-25-2017, 09:58 AM (This post was last modified: 12-03-2017 03:17 PM by jthole.)
Post: #1
HP 12C - refresh batteries or not?
Hello,

This week I found a HP 12C in great condition. It was clearly always taken care of very well, and came complete with the booklet and the pouch. According to the serial number, the calculator was made in 1993, in Singapore. The gentleman who sold it to me said that it was always used by his wife. It could very well still have the original batteries, but anyway, it has not been used for several years.

The calculator passes the self tests, and the screen does not show a low battery warning. However, given the low cost of LR44 batteries compared to the value of the calculator, would it be a good idea to refresh the batteries just in case? I bought it for fun, but I don't intend to take it with me as my daily calculator (I don't have an office desk, so it would have to travel in my laptop bag every day). So it will be idle here for most of the time as well.

BTW, as a carry everywhere calculator (and as a replacement for my bulky HP 35S) I ordered a SwissMicros DM15L. I have considered a DM16L, but while the binary operations and base conversions are great, it's been a few years already since I did serious programming and debugging. Given my demands, a DM11L would have done nicely as well, but I'm using a HP 15C emulator (and Free42) on my phone so I am used to the button layout anyway.

Thanks for any insights on the 12C battery replacement!
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11-28-2017, 01:53 PM
Post: #2
RE: HP 12C - refresh batteries or not?
Not sure why you're even asking the question Smile

Batteries are cheap so you might as well replace them to be on the safe side. They've been known to last for well over 10 years but do you want to risk leakage if they are the original ones?

Speaking of SwissMicros, have you considered the DM42, which is due to be released very soon (as in possibly within the next week)? Similar form factor to the HP-42S and a functional clone of it but on steroids (more memory, much faster, USB connectivity, really good 400x240 resolution LCD...)
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11-28-2017, 06:29 PM
Post: #3
RE: HP 12C - refresh batteries or not?
Yes, I already considered the cost of LR44 batteries, and bought a new set. Better safe than sorry :-)

About the DM42; yes, I looked at it, and I know that it will be available very soon. But it is severe overkill for me, and it is larger than the DM15L or HP 12C. As I don't have an office, I have to carry around everything in my laptop bag. So size counts :-)

Thanks for the suggestions! And I know it's been done before (and better), but yesterday night I wrote a small program to convert decimal numbers into binary ... it was fun to do :-)
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11-28-2017, 06:35 PM
Post: #4
RE: HP 12C - refresh batteries or not?
(11-28-2017 06:29 PM)jthole Wrote:  About the DM42; yes, I looked at it, and I know that it will be available very soon. But it is severe overkill for me, and it is larger than the DM15L or HP 12C.

I have both a DM42 and a DM15L (and every other "Voyager" DM machine). The 42 is indeed slightly taller than the 15L is wide, but the 15L is also slightly taller than the 42 is wide, so there's not much in it from that point of view. The 42 is also slimmer than the 15L Smile
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11-28-2017, 08:10 PM
Post: #5
RE: HP 12C - refresh batteries or not?
Wink

Well, I like the landscape layout of the DM15L ... I think it comes down to that Wink Maybe in the future there will also be a DM42 for me, who knows!
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11-29-2017, 07:40 AM
Post: #6
RE: HP 12C - refresh batteries or not?
(11-28-2017 08:10 PM)jthole Wrote:  Well, I like the landscape layout of the DM15L ... I think it comes down to that Wink Maybe in the future there will also be a DM42 for me, who knows!

There's a good chance that there will be a DM42L although I don't know when. Components have been chosen and we've made provision for it in parts of the firmware so it's looking like it will happen at some time.

Of course, other priorities might take precedence so this isn't a promise!
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12-03-2017, 02:50 PM
Post: #7
RE: HP 12C - refresh batteries or not?
That was a good decision; one of the batteries already had two pinpoints of corrosion. Since I bought a cheap ($15) Malaysian 12C for daily use, I have just removed the batteries of the older one, instead of installing fresh ones.

The Malaysian unit (1996) has a surprisingly good keyboard, even if it has painted keys. No rattle, and all keys have a positive 'click'.
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