HP41 Long term storage

[Steve Hunt]

Hi Folks,

I now seem to have accumulated 4 HP41s of various flavours - not sure how that happened, but it should ensure that at least one is working long after senility sets in :)

I find I am using two of them on a regular basis - one in my office and one in my radio shack. My question is: how best to keep all four in good working condition?

All 4 currently have batteries in; would it be better to remove the batteries from the 2 that are unused, and pack them away against the day one of the other 2 fails? If so, is it advisable to exercise them now and again? Or would it be sensible to "rotate" them all on a regular basis, say every week or every month.

Grateful for any views.

Regards,
Steve

[Raymond Del Tondo]

Quote:

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All 4 currently have batteries in; would it be better to remove the batteries from the 2 that are unused

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Yes, of course. Nearly every battery will leak after a certain time, and the HP-41 battery contacts are very sensitive against battery acid. Once the acid has reached the metal under the coating foil, the battery contacts will not be repairable anymore. If you see greeninsh particles on the golden battery contacts, carefully remove that residue, or it will move farther into the foil.

Additionally, the acid-filled gas will move into the inner case of the calc, starting to destroy the metal on the pcbs.

For the machines you use: Check the condition of the batts and contacts about every three months, and you should be able to find any leakage or acid attack before it's too late...

HTH

Ray

[Luiz C. Vieira (Brazil)]

Quote:

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Check the condition of the batts and contacts about every three months, and you should be able to find any leakage or acid attack before it's too late...

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Nothing else to say!

[Steve Hunt]

Yes, I know the battery leakage problem - I already lost one HP41 that way!

So, I should store the 2 spares with batteries removed and never power them up until one of the others fails?

Steve

[db (martinez, ca.)]

There is a theory that some electronic parts need current occasionally. I forget which. You could power them up every year, say on the Polish independence day, without doing any harm.

[Luiz C. Vieira (Brazil)]

Hi.

Matter of fact, no PERFECT electronic device needs to be occasionally powered, but such thing does not exist. Polarized capacitors, mainly the electrolytic type, are the ones prone to 'reorganize' themselves in terms of chemical mix inside of them, but after some time they usually need to be replaced after all. The other ones - ceramic, polyester, etc. - are more stable.

In any case, any electronic component suffer from chemical reactions, either inside of them or outside - atmospheric composition, oxygen included.

It is a good idea to power the 'little ones' from time to time. I'd give 6 months to one year resting time tops, but this is just a 'rule of thumb', cannot think of any scientific reason for the time period.

Hope this helps a bit.

Cheers.

Luiz (Brazil)

Edited: 27 Sept 2012, 9:53 p.m.

[db (martinez, ca.)]

Hi Luiz; Since the 41 IS perfect, or the CL is anyway, i guess that it would never need to be powered up at all.
But who could go a year without just a couple of calculations on any 41?