Why MEMORY LOST When turned on?

Discussion about the new DM41X calculator
HPMike
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Location: DFW, Texas

Re: Why MEMORY LOST When turned on?

Post by HPMike »

rprosperi wrote:
Thu Sep 22, 2022 2:31 am
As soon as you see the power-level is not 100%, change the battery (connect the USB cable to preserve power, and also remember to save your state file first).
So, are you saying that the calculator can be operated on USB power w/o a battery ?
DM15L, S/N 00548. DM42, SN: 00159. DM41X, SN: 00973.
rprosperi
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Location: New York

Re: Why MEMORY LOST When turned on?

Post by rprosperi »

HPMike wrote:
Thu Sep 22, 2022 2:54 am
rprosperi wrote:
Thu Sep 22, 2022 2:31 am
As soon as you see the power-level is not 100%, change the battery (connect the USB cable to preserve power, and also remember to save your state file first).
So, are you saying that the calculator can be operated on USB power w/o a battery ?
NO, you should not do that, however connecting the USB cable/power will preserve memory contents while you change the battery (machine should of course be OFF). If you change the battery quickly, this is typically not needed, but it's prudent to do so as you never know what can happen, like dropping the new battery, phone-call, etc. which can delay the replacement and lead to ML if the delay is too long without power.
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
Chumango
Posts: 10
Joined: Sat Apr 10, 2021 6:00 am

Re: Why MEMORY LOST When turned on?

Post by Chumango »

If this is the case there should be a disclaimer in the manual that says the battery indicator is only a general indication not to be trusted, and memory may be lost unexpectedly with no prior indication other than the battery indicator is not at the full 5 bars. But will even that be enough? Might this happen before it goes to 4 bars? Apparently there is no way to know.

This makes the DM41X inherently less reliable than I had previously thought.
redglyph
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Re: Why MEMORY LOST When turned on?

Post by redglyph »

It's concerning indeed. Has SM said anything about it?
rprosperi
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Location: New York

Re: Why MEMORY LOST When turned on?

Post by rprosperi »

The issue is not the reliability of the 41X, but rather one of poor quality CR2032 batteries. The circuitry in the 41X can only read and report the voltage the battery provides, and when the battery's voltage drops off a sharp cliff in almost no time, there is nothing than can be done. Using good quality batteries (e.g . Energizer) will allow continued operation with the gauge well below the top level, because the drop-off is not as steep.

There are numerous reports here for both DM42 and DM41X of similar 'failures' which ceased when the owner switched to higher quality batteries, so this is not just arm-waving. My advice to change batteries annually is simply prudent and allows one to spend less effort/focus on monitoring the battery level, especially if using cheap/poor quality cells.Hope this clears this up.
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
Chumango
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Joined: Sat Apr 10, 2021 6:00 am

Re: Why MEMORY LOST When turned on?

Post by Chumango »

Nothing from SM that I have seen, but I have not really been looking. Perhaps the question should be whether they even know about it. Apparently it is not just my calculator.

It displayed MEMORY LOST a couple of times this morning when turned on. So I found a screwdriver (at the office) and replaced the battery with Energizer. I also removed a couple of modules from active use.

Robert - this is the battery that came with the calculator from SM. If it qualifies as a poor quality battery then SM should change their supplier.
rprosperi
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Re: Why MEMORY LOST When turned on?

Post by rprosperi »

The cells SM uses are good quality, though of course there are variations in all large lots. How long have you owned the 41X, do you use it without USB connected when doing large amounts of Flash-intensive operations, do you use programs with very long run-time (e.g. many minutes) also not on USB?. If over a year and USB is never used for these situations then cell consumption is not abnormal, but if the unit is quite new and none of those things have been done, then it is of more concern.

Let me know about the above and I'll discuss it with Michael.
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
redglyph
Posts: 117
Joined: Sat Dec 22, 2018 11:45 am

Re: Why MEMORY LOST When turned on?

Post by redglyph »

rprosperi wrote:
Thu Sep 22, 2022 2:45 pm
The issue is not the reliability of the 41X, but rather one of poor quality CR2032 batteries. The circuitry in the 41X can only read and report the voltage the battery provides, and when the battery's voltage drops off a sharp cliff in almost no time, there is nothing than can be done. Using good quality batteries (e.g . Energizer) will allow continued operation with the gauge well below the top level, because the drop-off is not as steep.

There are numerous reports here for both DM42 and DM41X of similar 'failures' which ceased when the owner switched to higher quality batteries, so this is not just arm-waving. My advice to change batteries annually is simply prudent and allows one to spend less effort/focus on monitoring the battery level, especially if using cheap/poor quality cells.Hope this clears this up.
No worries, I don't know how much you are involved with SM but I'm not questioning the reliability of their DM41X (that I don't even own yet).

All I'm saying is that I would find it concerning not to know when the battery is about to fail, since it's a likely explanation. :)

Backup is a good safeguard policy but the USB requirement and my general laziness make that I don't do it very often. Regardless, that's what I would advise on top of the regular battery replacement. EDIT: saving the state in Flash would be enough, no need for USB.
Last edited by redglyph on Thu Sep 22, 2022 4:14 pm, edited 1 time in total.
Chumango
Posts: 10
Joined: Sat Apr 10, 2021 6:00 am

Re: Why MEMORY LOST When turned on?

Post by Chumango »

I received the unit on April 9, 2021.

I have never used it connected to USB.

I have not used flash-intensive applications. Every now and then I have used a program in an installed module (the standard modules that came with it).

I have not used large programs, just short ones used for solver or integration. Nothing more than a few seconds run time. Not very often.

I am an engineer who uses a calculator in the normal course of my day, but nothing heavy or specialized. No big programs or deep dives into computer science (chemical engineer). Most days I use a calculator at some point, some days more than others. I use this DM41X along with two other calculators (HP-41CV, HP-35S) so actual use time is split between them. Early on the other two saw more use while I was working from home, but over the last maybe 4 months I have used the DM41X most of the time since I carry it with me.
rprosperi
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Re: Why MEMORY LOST When turned on?

Post by rprosperi »

Chumango wrote:
Thu Sep 22, 2022 3:33 pm
I received the unit on April 9, 2021.

I have never used it connected to USB.

I have not used flash-intensive applications. Every now and then I have used a program in an installed module (the standard modules that came with it).

I have not used large programs, just short ones used for solver or integration. Nothing more than a few seconds run time. Not very often.

I am an engineer who uses a calculator in the normal course of my day, but nothing heavy or specialized. No big programs or deep dives into computer science (chemical engineer). Most days I use a calculator at some point, some days more than others. I use this DM41X along with two other calculators (HP-41CV, HP-35S) so actual use time is split between them. Early on the other two saw more use while I was working from home, but over the last maybe 4 months I have used the DM41X most of the time since I carry it with me.
Thanks for the detailed reply. Yes, well over a year of use can lead to battery depletion, so it's probably as simple as that. Depending on usage, some batteries can last 2 years or more, but a year is not unusual, which is why my advice is to change it annually.

I hope this clears it up and your confidence in the DM41X is restored.
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
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