A few suggestions to improve the hardware DM41.

Discussion of hardware issues related to the DM1x/DM41. Please ensure that you specifiy whether the issue is related to a credit card size unit or a "Voyager" unit (DM1xL/DM41L).
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agusDM41
Posts: 5
Joined: Sun Oct 31, 2021 4:25 pm

A few suggestions to improve the hardware DM41.

Post by agusDM41 »

Just a few suggestions to improve the hardware of the swissmicros DM41.

The plastic between the LCD and the transparent keypad window is not necessary, it also creates problems by sticking to the LCD and giving a water print underneath due to sticking. I have removed it.

If you press too hard on the keyboard area on the battery, a short circuit can occur sometimes and the memory is erased and I think it is due to a not very good soldering of the battery box with the PCB when PCB is hard pressed.
In any case, the anti-short circuit sticker seems unnecessary since titanium is a very poor conductor and I tried to create a short between the + pole and the titanium housing without plastic sticker over battery and it was impossible produce a MEMORY CLEARED but touching with copper cable pole + and the house of screws produce a MEMORY CLEARED.

I think that the battery box and the pressure and deformation of the PCB in that area should be studied to prevent resets.
Test it without titanium housing and deform gently a little the PCB and in certain cases ... reset.

I have solved these problems with a good cleaning of the battery box and putting a conductive metal type washer between the + pole of the battery and the battery case so that there is no gap and the battery is firmly seated no matter how much pressure is applied on it from the keyboard.

Improve the soldering of the + pole with the PCB and the internal contact of the battery on the negative pole since it looks dirty even after cleaning it and does not see gold or silver.

Less glue near the domes of the keys since pressing hard sometimes they stay stuck and you have to detach the keyboard and stick it again to release them.Now is working fine to me after two times remove keyboard and put again.

Just 1mm or 1,5mm of glue grid around the keys I think would improve tactile feedback and prevent keyboard issues and noise when the key is lifted and "dragged" on the keyboard giving an unpleasant adhesive noise.

The screws 0,5mm or 1mm less long to prevent push keyboard up.
Write on the back of DM41 RESET hole to not confuse the two holes RESET ... PGM.

After all a great product and idea that can be better with some improvements in hardware.
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DM41-october-2021.jpg
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Last edited by agusDM41 on Sun Oct 31, 2021 11:00 pm, edited 1 time in total.
agusDM41
Posts: 5
Joined: Sun Oct 31, 2021 4:25 pm

Re: A few suggestions to improve the hardware DM41.

Post by agusDM41 »

A correction to the previous comment.
A short circuit does occur when touching the titanium case with the battery case.
I forgot to attach the titanium case to the battery negative to check this :roll:
I just realized right now. Sorry for the mistake.
The insulating sticker is necessary although I have put a very thin insulating adhesive strip all over the inside of the titanium case.
The rest of the comment is correct in my appreciations.
agusDM41
Posts: 5
Joined: Sun Oct 31, 2021 4:25 pm

Re: A few suggestions to improve the hardware DM41.

Post by agusDM41 »

As an additional note to say that I like this "old" type of electric welding much more for the battery house ... see attached photo. I don't know if one type of welding is better than the other.
As for the sticky sound of the keyboard, only sometimes in some key happens but is an ugly noise.

I value much more the robustness of the calculator than those small details but the tactile sensation of the keyboard could perhaps be improved with another type of adhesive that in case of loosening a little does not make a sticky noise.
Maybe a very thin layer of adhesive silicone around the keys could give it some fluffiness without sticky noise?
I don't know, for sure SwissMicros has tried the most things. I just contribute a few ideas.
It works well for me by ignoring those little details and I love the size and light weight.

A great idea to have put all this in such a small space.
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old-welding-battery-case.jpg
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johanw
Posts: 16
Joined: Sun May 24, 2020 6:41 pm

Re: A few suggestions to improve the hardware DM41.

Post by johanw »

I noticed something like this myself - my DM41 suddenly stopped working so I assumed a flat battery. I opened it - which required some force because one of the screws didn't cooperate - and saw suddenly some memory resets occuring. When I just reassembled it it has kept working normally since then, on the same battery so something must have short circuited or broken a circuit before. I've never had this with my DM15 which has the construction as shown in the last pucture.
DMaier
Posts: 16
Joined: Sun Jul 09, 2017 5:09 am

Re: A few suggestions to improve the hardware DM41.

Post by DMaier »

agusDM41 wrote:
Sun Oct 31, 2021 6:24 pm
The plastic between the LCD and the transparent keypad window is not necessary, it also creates problems by sticking to the LCD and giving a water print underneath due to sticking. I have removed it.
Hi agusDM41, I'm wondering if I might be experiencing this issue... Were you seeing something like this?
DM41 LCD issue
DM41 LCD issue
dm41 display issue small.jpg (84.13 KiB) Viewed 579 times
EDIT: Yes, I can confirm that was it. Simple fix.
agusDM41
Posts: 5
Joined: Sun Oct 31, 2021 4:25 pm

Re: A few suggestions to improve the hardware DM41.

Post by agusDM41 »

Yes, I opened the calculator and removed that internal plastic so that it doesn't make that mark on the display of the digits. You can see in the first photo on this post up right the result. See it on the edge of window digits.
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