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Re: buttons that don't register well

Posted: Wed Apr 18, 2018 12:18 am
by jtucker
I just got My DM42. The keyboard inputs are somewhat iffy as some have noted. Other than the keyboard, it is a very nice design. Like many, I need a totally reliable input for work. No double strikes, no missed inputs. I will want a second unit for home as I very much rely on "muscle memory" for on the fly calculations. As a working electrical engineer, I still use a handheld calculator daily. I've been using HP 35s, but the lack of named variables is a big limitation. I keep a large amount of equations in the "solver". It would be way superior if I could name the variables. I have looked at the HP Prime as well. Nice key feel, great solver app, but the RPN implementation and the screen resolution leave a lot to be desired. But for me the keyboard is the "make or break" factor. My initial tear down indicates that the keyboard ( as noted elsewhere) is too close the the key domes. I would suspect that some type spacer is required between the key matrix and the PCB. I'm going to hold off on buying a second DM42 until this is resolved.

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 7:08 am
by Rmollov
Michael wrote:
Thu Apr 12, 2018 11:13 am
I'm sorry for this. Finally we nailed the problem with the ENTER button.
The unequal tactile feedback is caused by the upwards bent ABS housing.
Once the calculator is taken apart and warmed up a little, it can be bent back which should solve the issue.
Please give it a try. Otherwise you can send it back to me and I'll fix it.
Hi Michael,
The above may be one of the reasons, but there is another as can be seen on the photos...
Image
Image

Regards,

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 7:13 am
by Michael
Rmollov wrote:
Wed Apr 18, 2018 7:08 am
The above may be one of the reasons, but there is another as can be seen on the photos...
That looks strange. Please take it completely apart, gently press the enter button from behind and put it back together.
I hope it solves the issue.

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 8:22 am
by mcc
Hi,

I think it's not the ENTER button...the hole thing
isn't plane as it seems to me.
On the lower part of that photo take a look
at the "STO"-button and compare it with the
"R(down)"-button for example...

Only my two buttons...your buttons may vary... ;)

Cheers!
m

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 8:33 am
by Walter
mcc wrote:
Wed Apr 18, 2018 8:22 am
Only my two buttons...your buttons may vary... ;)
:lol: But seriously, this whole topic looks like a matter of production variance. :|

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 8:35 am
by Zaphod
mcc wrote:
Wed Apr 18, 2018 8:22 am
Hi,

I think it's not the ENTER button...the hole thing
isn't plane as it seems to me.
On the lower part of that photo take a look
at the "STO"-button and compare it with the
"R(down)"-button for example...
He's right :shock: , maybe some foreign object inside stopping that area of the PCB being screwed down properly?

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 11:42 am
by H2X
Zaphod wrote:
Wed Apr 18, 2018 8:35 am
He's right :shock: , maybe some foreign object inside stopping that area of the PCB being screwed down properly?
Chinese, if I am not mistaken? :-)

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 11:54 am
by Zaphod
H2X wrote:
Wed Apr 18, 2018 11:42 am
Chinese object
Doesn't have quite the same ring to it :D

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 12:06 pm
by jtucker
Yes it looks like mcc just has a a worse condition than mine. The pcb is attached to the keyboard in only two places. As a intermediate partial solution, when I re-assembled my DM42 after tightening the two screws, I backed them out a quarter turn. To prevent them from moving I used a little blue loctite on them. There is nothng to prevent the keyboard and pcb from cantilevering though. 4 screws would probably have been a good idea. I think some spacers between the keyboard and pcb with a non-permanent adhesive might work. I really want to like this...

Re: buttons that don't register well

Posted: Wed Apr 18, 2018 1:23 pm
by H2X
Rmollov wrote:
Wed Apr 18, 2018 7:08 am
The above may be one of the reasons, but there is another as can be seen on the photos...
Comment: Does the faceplate (with the printed labels on) stick firmly to the calculator all over? Seems that it might be a bit loose along the left side.