[DM42] Bug when turned on?

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keithdalby
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[DM42] Bug when turned on?

Post by keithdalby »

Good morning calculator fans,

When I first turn my calculator on after it being off for a little while (I don't know specifically how long), the screen has missing elements. It is not always the same missing elements each time this happens, but it happens every time. Here's a video of a particularly bad example:

https://youtu.be/CDtlJYWs16s

Here, when turned on, the screen remained completely blank (my 'screensaver' image is deliberately blank when turned 'off'). You can see what happens with my key presses, a number reveals some of the screen elements, but not the bit at the top.

This has become such a nuisance (having to press a few buttons to see everything) that I've actually stopped using my DM42 now. Is this a known bug? Is there a fix?

DMCP v3.18
DM42 v 3.15
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akaTB
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Re: [DM42] Bug when turned on?

Post by akaTB »

Interference from the static caused by your hairs?
:mrgreen:
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keithdalby
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Re: [DM42] Bug when turned on?

Post by keithdalby »

If folk are running the same software and not having the same issues, does that make this a hardware issue?
EM41
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Re: [DM42] Bug when turned on?

Post by EM41 »

I don't see this here also not with a blanc off screen.

edit: With the 41X, that i use most, I had to do a few serious "paperclip of death" resets because of experiments, maybe its a good idea to do that and format also the FAT disk before concluding its the hardware.
Last edited by EM41 on Thu Jun 04, 2020 9:51 pm, edited 1 time in total.
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PierreMengisen
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Re: [DM42] Bug when turned on?

Post by PierreMengisen »

keithdalby wrote:
Thu Jun 04, 2020 11:16 am
actually stopped using my DM42
Is it the same behaviour when powered by USB?
Pierre
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gduncan
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Re: [DM42] Bug when turned on?

Post by gduncan »

keithdalby wrote:
Thu Jun 04, 2020 11:16 am
When I first turn my calculator on after it being off for a little while (I don't know specifically how long), the screen has missing elements. It is not always the same missing elements each time this happens, but it happens every time. Here's a video of a particularly bad example:
You may have a faulty ribbon connector on the LCD. I had to replace my LCD screen as I was experiencing a very similar issue. I am pretty sure that my LCD ribbon was damaged due to me taking the calculator apart so many times to address the keyboard issues. Michael at SM was able to sell me the LCD only. I replaced it, and everything worked fine.
keithdalby
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Re: [DM42] Bug when turned on?

Post by keithdalby »

PierreMengisen wrote:
Thu Jun 04, 2020 9:03 pm
keithdalby wrote:
Thu Jun 04, 2020 11:16 am
actually stopped using my DM42
Is it the same behaviour when powered by USB?
Good suggestion. I've been doing some testing, and it only happens when battery powered. The battery meter on the calculator shows that it's fine 🤷 any suggestions?
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Walter
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Re: [DM42] Bug when turned on?

Post by Walter »

keithdalby wrote:
Tue Jun 09, 2020 6:17 pm
PierreMengisen wrote:
Thu Jun 04, 2020 9:03 pm
keithdalby wrote:
Thu Jun 04, 2020 11:16 am
actually stopped using my DM42
Is it the same behaviour when powered by USB?
Good suggestion. I've been doing some testing, and it only happens when battery powered. The battery meter on the calculator shows that it's fine 🤷 any suggestions?
What does 'fine' mean in volts? (I once thought this is a technical forum ... :roll: )
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grsbanks
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Re: [DM42] Bug when turned on?

Post by grsbanks »

Walter wrote:
Tue Jun 09, 2020 6:58 pm
What does 'fine' mean in volts? (I once thought this is a technical forum ... :roll: )
Keith is a physics teacher. I'm sure he is able to ascertain what voltage range is "fine" himself.
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akaTB
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Re: [DM42] Bug when turned on?

Post by akaTB »

Maybe the voltage is fine, but not the capacity.
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