Subject: Re: Thanks - was Re: Cool calculator

From: Joe <[email-masked]>
Date: Thu Apr 3 20:06:05 2003

John,

  What type and brand of batteries were they? Sounds like good ones to avoid!

   Joe

At 10:44 PM 4/3/03 +0100, you wrote:
>Keys wrote:
>> From: "Tony Duell" <[email-masked]>
>>>Oh yes, it _eats_ batteries. Officially you're supposed to use 4 D-size
>>>NiCds. It will run of alkaline cells, but it drains them in a few minutes
>>>(!).
>
>Just a quick cautionary tale about batteries; we have a digital camera
>at the office, a cheap Logitek one. We used it all day, for five days
>and on the last day, the batteries burst inside the battery compartment.
>We suddenly had hot, caustic battery electrolyte all over the place!
>Now, it doesn't really matter with a modern, off-the-shelf gadget, but
>with an irreplaceable classic, it could be more serious.
>
>Do check that the batteries you use don't start to overheat!
>
>--
>John Honniball
>[email-masked]

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From: "Keys" <[email-masked]>
Date: Fri Apr 4 12:37:19 2003

I picked up a Compucorp 324G Scientist calculator/micro computer at a thrift
today for $8.08. Seems to work great.

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From: [email-masked] (Tony Duell)
Date: Fri Apr 4 12:37:39 2003

> today for $8.08. Seems to work great.

I have one too, found at a radio rally (hamfest) for about the same 
amount of money.

As you've realised by now, it's programmable, in that it will remember a 
seqeunce of keys, and when it gets to the end, it restarts from the 
beginning. There are no labels or jumps, though. The only waty to stop a 
program is either to record a start/stop key, or for an error to occur. 
The user manual gave a number of programs that would force an error after 
a given number of iterations, thus allowing the machine to calculate 
factorials, etc.

The 2nd function key is strange. It's pressed _after_ the other key. So 
that, for example SIN and COS are on the same key. Press that key to 
calculate one of them (I forget which), then press 2nd function to get 
the other.

Inside there are 4 circuit boards IIRC, stuffed with 40 pin custom chips 
(and some standard RAMs and PSU parts). 

It's one of the first programmable calculators -- the 322 (same machine 
with half the memoey) predates the HP65 by a few weeks, or so I was told.

-tony

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From: "Keys" <[email-masked]>
Date: Fri Apr 4 12:37:45 2003

Thanks for the tips, I also found some sample programs on the web.

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From: John Honniball <[email-masked]>
Date: Fri Apr 4 12:37:48 2003

--
John Honniball
[email-masked]

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From: [email-masked] (Tony Duell)
Date: Fri Apr 4 12:37:58 2003

> and on the last day, the batteries burst inside the battery compartment.

Ouch!!! How did it managhe that? Drawing excessive current from the 
battery? 

> with an irreplaceable classic, it could be more serious.

If I bought a device that caused the batteries to explode, not only would 
I want a full refund, I'd _never_ buy anything from that company again. 
Still I knew there was a reason why I use cameras that don't need 
batteries at all...

> Do check that the batteries you use don't start to overheat!

The Compucorp 324 draws a high current (of the order of 1A I think), but 
it shouldn't be high enough to cause the batteries to explode...

-tony

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From: John Honniball <[email-masked]>
Date: Fri Apr 4 12:38:02 2003

> Ouch!!! How did it managhe that? Drawing excessive current from the 

I presume so, yes.  Or conceivably, trying to charge the alkaline
cells from the USB power input?  I didn't actually see it happen, but
I did get to clean up the mess.

> I want a full refund, I'd _never_ buy anything from that company again.

Quite agree!

--
John Honniball
[email-masked]

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From: Mark Tapley <[email-masked]>
Date: Fri Apr 4 12:38:30 2003

Everyone interested in a VAXstation 4000VLC,
	a while ago I put out an announcement about a batch of these I was
going to pick up and distribute. The pick-up trip will be this Saturday,
05-Apr. If you are not on this list:

Brian Chase, Neil Carpenter, John Allain, Paul Thompson, adrian/witchy

	I have not heard from you. If you tried to contact me, try again
harder. If I hear from you by 1700 CST = 2300 UTC, Friday, 04-Apr-2003,
I'll try to add you in.
	If you are on the list above, I'm emailing you separately to
double-check.
							- Mark

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From: Bryan Blackburn <[email-masked]>
Date: Fri Apr 4 12:38:33 2003

It is hard to imagine that the batteries could have been the problem. 
Most likely, something was charging the battery. This is common if the 
device supports rechargeables as an option (whether or not it was 
purchased with that option), and the right jumper is in place or a 
switch gets flipped. Having repaired countless consumer electronic 
items, I've seen it many times. Another likely possibility is if one 
cell is reversed in the pack, thereby receiving a charge.

-Bryan

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From: Tothwolf <[email-masked]>
Date: Fri Apr 4 12:38:40 2003

On Thu, 3 Apr 2003, John Honniball wrote:
> I presume so, yes.  Or conceivably, trying to charge the alkaline cells
> from the USB power input?  I didn't actually see it happen, but I did
> get to clean up the mess.

I'd imagine something tried to charge one or more of the cells.
Theoretically, you can (sometimes) charge an Alkaline cell, under
controlled conditions, if it is not completely depleted, but you still run
the risk of splitting its case or blowing its seal. This is especially
true with cells that use cheaply made cases (I've seen cells that lacked
vents, and some that had very bad seals) and/or if too much current is
available while charging. Now, I'd still _not recommend_ anyone try to
charge primary cells, and under no circumstances should anyone ever
attempt to charge such batteries in a standard NiCad charger...

> > If I bought a device that caused the batteries to explode, not only
> > would I want a full refund, I'd _never_ buy anything from that company
> > again.
>
> Quite agree!

If you decide to clean up after the incident, plain old vinegar will help
remove the alkaline electrolyte. Of course, you also have to completely
rinse off the vinegar, or it will begin to corrode metals too.

Still, it could have been worse... A carbon-zinc cell's electrolyte will
stain plastics orange, and will also eat away battery contacts in a fairly
short time period.

-Toth

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From: Don Maslin <[email-masked]>
Date: Fri Apr 4 12:38:48 2003

>   What type and brand of batteries were they? Sounds like good ones to avoid!

This reminds me that just the other day I saw a calculator in a
thrift, IIRC, that carried the message to remove the batteries
if you were going to run it on the wallwart for more than four
hours to avoid over heating the alkaline cells.  Sounds like a
similar problem?
						- don

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From: [email-masked] (Tony Duell)
Date: Mon Apr 7 12:40:19 2003

> hours to avoid over heating the alkaline cells.  Sounds like a

I have a couple of 4-function Commodore calculators that have a warning 
on the back to 'unsnap and remove the battery if using the PSU' (or words 
to that effect). 

Decimo VATman calculators (a popular 1970s model in the UK, so called 
because it had a % key, and was useful for working out VAT (sales tax)) 
have a 3 position power switch. Off, On, and Charge. There's a warning 
not to use the Charge position unless you fit NiCds...

Casio got it right (for once). Their machines took a special NiCd battery 
pack consisting of 2 AA cells in a plastic holder. When it was inserted, 
a peg on the plastic holder closed a switch in the battery compartment, 
enabling the charger circuitry. Of course hackers (like me), soldered a 
jumper across the switch and put normal AA NiCd cells in (a pair of those 
was a lot chaaper then the battery pack), but we can't blame the 
manufacturer for that.

HP and TI often designed machines to run off the (special) rechargeable 
NiCd pack only.

-tony