Why MEMORY LOST When turned on?

Discussion around the SwissMicros DM41X calculator
Chumango
Posts: 17
Joined: Sat Apr 10, 2021 6:00 am

Why MEMORY LOST When turned on?

Post by Chumango »

I just turned my DM41X on and it displayed MEMORY LOST. The battery is fine, so that should not be an issue.

What might cause this, and how might I prevent this in the future? I'd really like to trust it to keep programs.
rprosperi
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Joined: Mon Apr 24, 2017 7:48 pm
Location: New York

Re: Why MEMORY LOST When turned on?

Post by rprosperi »

Chumango wrote:
Mon Sep 19, 2022 3:08 pm
I just turned my DM41X on and it displayed MEMORY LOST. The battery is fine, so that should not be an issue.

What might cause this, and how might I prevent this in the future? I'd really like to trust it to keep programs.
It's impossible to suggest the cause without a LOT more information, however the most likely cause is either a drop/hit which may have jarred the electronics on the board, or battery near end of life (how do you assess the battery is fine?), etc.

Did you save your state file? If so, just load it back in ([shift] [SETUP] [1] [1] and pick your state file).

What ROM configuration were you using, this can cause problems if using some combinations of exotic ROMs.

hth
--bob p

DM42: β00071 & 00282, DM41X: β00071 & 00656, DM10L: 071/100
redglyph
Posts: 177
Joined: Sat Dec 22, 2018 11:45 am

Re: Why MEMORY LOST When turned on?

Post by redglyph »

There was a similar report last winter, when it was colder as it is now, at least in Europe. The author only made 1 post (and duplicate) without any reply so I don't know what the conclusion was.

Indeed, more information would be required. Also, have you left it switched off for a long time, did it go through environmental changes (temperature, humidity)? Did it only happen once, ...?
Chumango
Posts: 17
Joined: Sat Apr 10, 2021 6:00 am

Re: Why MEMORY LOST When turned on?

Post by Chumango »

It was not dropped, and there have been no significant temperature changes. It is used on a regular basis, at least several times a week. The battery indicator says most of the battery life remains.

It has only happened once in the 17 months I have had it. I am the original owner.

I have not uploaded any unusual ROM. I have a few of the standard modules loaded, the ones that come with it. Advantage, Math, Chemical Engineering, and one other I don't recall. Otherwise it is configured in the default from SwissMicros.
Chumango
Posts: 17
Joined: Sat Apr 10, 2021 6:00 am

Re: Why MEMORY LOST When turned on?

Post by Chumango »

It just happened again. I used it briefly last night, and when I turned it on this morning it showed memory lost. The battery indicator shows 4 of 5 bars.

It first came up with a setup screen. When I exited that screen it said memory lost.

I don't know if this is important but it says no state file at the top ribbon. I have never done anything with state files.
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HP41CV
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Location: Germany

Re: Why MEMORY LOST When turned on?

Post by HP41CV »

I got also "Memory Lost" after switching on. Battery was also 4of5 so I thought it could not be the battery.

To make long story short: It was the battery! After I changed it no problem until it was again 4of5 after some weeks...again "Memory Lost"...replaced battery again...no prob...

I have no clue why 4of5 is not sufficient power on my DM41X, but it is. Now on my third battery within some months and when I switch it on it shows briefly 4 than back to 5. Usage is very seldom, only some minutes every now and then.

PS: I don't use cheap batteries...
Stephan
HP41CV/HP71B/HP48GX/DM41X
Required
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Re: Why MEMORY LOST When turned on?

Post by Required »

Is the boot process so power consuming that the cell - or some cells - can’t deliver the needed current and therefor drops the voltage so deep that the memory is lost?
I’m the Required one.

42S: 3117S03858 | DM42: 08455 | DM32: 00166 | 15C CE: 00085
Chumango
Posts: 17
Joined: Sat Apr 10, 2021 6:00 am

Re: Why MEMORY LOST When turned on?

Post by Chumango »

I don't use cheap batteries either, though I think the battery is the one that came from SM.

Do I need to replace the battery every year regardless of what the battery indicator says?
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HP41CV
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Location: Germany

Re: Why MEMORY LOST When turned on?

Post by HP41CV »

I got mine exactly one year ago, since then 3 batteries (inclusive the original supplied one from SM)...
Stephan
HP41CV/HP71B/HP48GX/DM41X
rprosperi
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Re: Why MEMORY LOST When turned on?

Post by rprosperi »

When unexpected and/or unexplained ML occurs, the first thing you should do is replace the battery, with a brand-new, high-quality battery. The extremely rapid fall-off voltage of lithium coin cells makes it difficult (impossible?) to make any kind of linear fuel gauge, as can be seen by these observations.

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).

And I'd say yes, you should plan to replace the battery every year or so, to prevent exactly this kind of situation. Of course battery consumption directly relates to how, and how much you use your device, but it's probably worth the $2/year to not have to worry about what the battery condition is.

Note: One feature in the 41X that uses more than expected power is extensive loading of modules, as this involves flash writing which consumes more power than normal calculator operation.
--bob p

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