HP-41CV: Strange "Power Management"

[JurgenRo]

I own a HP-41CV that otherwise works flawlessly, except for one quirk : If the calculator is switched off for more than 12 hours (experiment under memory lost condition), it can no longer be switched on. After removing and reinserting the batteries, everything works fine again. Any ideas anyone?

Thanks in advance
Juergen

[TallKey]

(05-06-2023 05:59 PM)JurgenRo Wrote:  I own a HP-41CV that otherwise works flawlessly, except for one quirk : If the calculator is switched off for more than 12 hours (experiment under memory lost condition), it can no longer be switched on. After removing and reinserting the batteries, everything works fine again. Any ideas anyone?

Thanks in advance
Juergen

First thought is the 41 is detecting low battery and will remain off.

Is the calculator speed modded (time to complete CAT 3 is)?
Are you the original owner?
NO modules, same failure?

-Test for 1.3v or above per cell. Can't recall the min operable number, about 1.3v ought to give you good results.

[JurgenRo]

(05-06-2023 08:33 PM)TallKey Wrote:  

(05-06-2023 05:59 PM)JurgenRo Wrote:  I own a HP-41CV that otherwise works flawlessly, except for one quirk : If the calculator is switched off for more than 12 hours (experiment under memory lost condition), it can no longer be switched on. After removing and reinserting the batteries, everything works fine again. Any ideas anyone?

Thanks in advance
Juergen

First thought is the 41 is detecting low battery and will remain off.

Is the calculator speed modded (time to complete CAT 3 is)?
Are you the original owner?
NO modules, same failure?

-Test for 1.3v or above per cell. Can't recall the min operable number, about 1.3v ought to give you good results.

Calc is not modded, fresh batteries, no modules, MEMORY LOST condition ...

[rprosperi]

(05-06-2023 08:36 PM)JurgenRo Wrote:  Calc is not modded, fresh batteries, no modules, MEMORY LOST condition ...

It may not be the case, but because batteries are new/fresh does not mean they re full voltage. It's 2023, it just happens.... and a lot more often than you'd think.

I'd check the voltage of them to be certain...

[JurgenRo]

(05-06-2023 11:12 PM)rprosperi Wrote:  

(05-06-2023 08:36 PM)JurgenRo Wrote:  Calc is not modded, fresh batteries, no modules, MEMORY LOST condition ...

It may not be the case, but because batteries are new/fresh does not mean they re full voltage. It's 2023, it just happens.... and a lot more often than you'd think.

I'd check the voltage of them to be certain...

You'ne right, Bob. Installed another set of batteries yesterday and the calc switched on just a minute ago - after 14 hours! Hopes are that it just was bad batteries. Thanks again!

Juergen

[rprosperi]

(05-07-2023 06:38 AM)JurgenRo Wrote:  You'ne right, Bob. Installed another set of batteries yesterday and the calc switched on just a minute ago - after 14 hours! Hopes are that it just was bad batteries. Thanks again!

Juergen

Good news!! Thanks for confirming so here, it may inspire readers that this unlikely solution can work.

Honestly most people ignore this advice, convinced new cells can't possibly be bad; I too thought the same for a far long period of time. Among other reasons, I only buy the more expensive brands (e.g. Energizer) to minimize this, but even among these it happens.

[JurgenRo]

(05-07-2023 12:40 PM)rprosperi Wrote:  

(05-07-2023 06:38 AM)JurgenRo Wrote:  You'ne right, Bob. Installed another set of batteries yesterday and the calc switched on just a minute ago - after 14 hours! Hopes are that it just was bad batteries. Thanks again!

Juergen

Good news!! Thanks for confirming so here, it may inspire readers that this unlikely solution can work.

Honestly most people ignore this advice, convinced new cells can't possibly be bad; I too thought the same for a far long period of time. Among other reasons, I only buy the more expensive brands (e.g. Energizer) to minimize this, but even among these it happens.

I can confirm this, the bad batteries were brand new Duracells, which belong to the expensive ones. Lessons learned!!

[rprosperi]

(05-08-2023 07:16 PM)JurgenRo Wrote:  

(05-07-2023 12:40 PM)rprosperi Wrote:  Good news!! Thanks for confirming so here, it may inspire readers that this unlikely solution can work.

Honestly most people ignore this advice, convinced new cells can't possibly be bad; I too thought the same for a far long period of time. Among other reasons, I only buy the more expensive brands (e.g. Energizer) to minimize this, but even among these it happens.

I can confirm this, the bad batteries were brand new Duracells, which belong to the expensive ones. Lessons learned!!

Ouch! Another Duracell victim..... NEVER, EVER put any Duracell batteries into an HP Calculator (or probably anything else). As far back as the 71B, HP advised customers to NOT use Duracell batteries due to the likelihood that they would leak and damage the device.

[JanS]

I'm strongly seconding the "do not use Duracell" notion.
I bought A MiniMaglite AA Pro LED flashlight for around 50 Euros and was delighted to find it came with a pair of batteries included. Eagerly installed them and put the flashlight in the car's trunk for future use.
A year later: No joy :-(
The cells had leaked and expanded / bonded to the aluminum/aluminium casing, making a battery change impossible and rendering the whole thing a metal encased piece of toxic waste. Checking the MagLite Solitaire LED bought at the the same time (which also came with a single AAA Duracell) revealed the exact same thing - another piece of metal encased toxic waste. (One might presume Maglite has a clever demand generating theme here)

Morale of the story: Get rid of the Duracells, replace with good Brand Cells and (at least for Maglites / high value flashlights) even when not using, replace cells once a year to protect the investment in the flashlight.
I've switched to Eneloops and so far I like what I see in terms of charge retention over the one-year change cycle and haven't experienced a single Cell leakage. Now, to keep this HP related: Anyone know where to find 1N Eneloops ;-) ?

[JurgenRo]

(05-08-2023 07:28 PM)rprosperi Wrote:  

(05-08-2023 07:16 PM)JurgenRo Wrote:  I can confirm this, the bad batteries were brand new Duracells, which belong to the expensive ones. Lessons learned!!

Ouch! Another Duracell victim..... NEVER, EVER put any Duracell batteries into an HP Calculator (or probably anything else). As far back as the 71B, HP advised customers to NOT use Duracell batteries due to the likelihood that they would leak and damage the device.

Didn't Know that, thanks a lot for letting meine know!

[JurgenRo]

(05-08-2023 07:28 PM)rprosperi Wrote:  

(05-08-2023 07:16 PM)JurgenRo Wrote:  I can confirm this, the bad batteries were brand new Duracells, which belong to the expensive ones. Lessons learned!!

Ouch! Another Duracell victim..... NEVER, EVER put any Duracell batteries into an HP Calculator (or probably anything else). As far back as the 71B, HP advised customers to NOT use Duracell batteries due to the likelihood that they would leak and damage the device.

Didn't Know that, thanks a lot for letting meine know!

[Jonas Sandstedt]

And never do what I did - although being an electrical engineer.
I put in four A23 12V cells in a cosmetically excellent 41c I had bought in a bundle of HP calculators.
After trying to revive the calculator without success, I sent it to The Calculator Store, and it ended up that they could keep it for parts. I have written about this before, but it should be repeated since it only takes a couple of moments of “non-thinking” to destroy a fine calculator.
Best regards
Jonas