Unexpected resets on DM41L with v22

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[DM16 V22] CHS gives unexpected results
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SparksZA
Posts: 2
Joined: Thu Nov 16, 2017 6:17 am
Location: Pretoria, South Africa

Unexpected resets on DM41L with v22

Post by SparksZA » Thu Nov 16, 2017 6:31 am

I have DM41L s/n 00223 and I am experiencing occasional resets (with full memory loss) while doing normal calculations, ie not entering or running programs.
Unfortunately the occurrence is quite rare, so quite hard to reproduce. However it's happened to me perhaps a half a dozen times over the past year that I've owned the DM41L, always under much the same circumstances, ie when doing normal calculations at speed.
As best I can pin it down, it seems to occur when entering numbers and doing operations (+,-,*,/ etc), most often when pressing keys around the 4,5,6 area of the keyboard. Most probably I am in USR mode when this occurs, however with no custom key mappings in that area. When it happens mid-calculation, I get the DM41L title screen followed by the 'MEMORY LOST' display.
This is with v22 firmware, I still need to do the v23 upgrade.

I realise this isn't particularly helpful as a bug report until I can reproduce the sequence of events that causes this to happen, however I'm just wondering if I'm alone in this or whether someone else has experienced the same.

Other than that, loving my DM41L. So good to have an RPN machine that so closely mirrors the legendary original.

Cheers

Michael
Site Admin
Posts: 236
Joined: Wed Apr 05, 2017 9:31 pm

Re: Unexpected resets on DM41L with v22

Post by Michael » Thu Nov 16, 2017 6:40 am

Please check if there is an EVA foam pad on top of the battery holder.

SparksZA
Posts: 2
Joined: Thu Nov 16, 2017 6:17 am
Location: Pretoria, South Africa

Re: Unexpected resets on DM41L with v22

Post by SparksZA » Thu Nov 16, 2017 3:59 pm

Indeed it does have one.
I see that the battery holder is on the opposite side of the PCB to the numeric part of the keypad, so a link seems unlikely.
Good suggestion though!
I can detect no sensitivity to pressure (eg loss of contact between battery and holder) on that part of the keyboard, so it looks like the cause may lie elsewhere.

I have just done the upgrade to v23 without incident, so I'll continue to monitor this issue and see how things go.

Cheers

Michael
Site Admin
Posts: 236
Joined: Wed Apr 05, 2017 9:31 pm

Re: Unexpected resets on DM41L with v22

Post by Michael » Thu Nov 16, 2017 4:10 pm

The battery holder is connected to +3V and if you press hard enough and there is no pad on top of the battery holder it presses against the housing which is connect to the GND and it shortens the battery...

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