What am I doing wrong - HP42 (DM42)
10-03-2022, 04:32 PM
Post: #1
 rkumetz Junior Member Posts: 3 Joined: Oct 2022
What am I doing wrong - HP42 (DM42)
I have a DM42 HP42 clone which is very nicely made but I am having some problems
which I am sure is something I am doing wrong because I have been using an HP28C
until it recently became too intermittent to rely on.

I have the calculator in DECM mode and SCI 10 display mode.

If I do this: 10 [ENTER] 2 [DIVIDE] I get (predictably) a result of 5

If I do this: 6.022 E 23 [ENTER] 2 [DIVIDE] I get an INVALID DATA message.

What is my feeble overly excited to have a cool new calculator brain doing wrong?
10-04-2022, 02:18 AM
Post: #2
 rprosperi Super Moderator Posts: 5,855 Joined: Dec 2013
RE: What am I doing wrong - HP42 (DM42)
Some things to try, in this order, checking if it's fixed after each step:

1. Shift-SETUP-2 Load Clean State

2. Insert a paper-clip into the reset hole on the back side

3. Reinstall the latest DM42 firmware, available here:
https://forum.swissmicros.com/viewtopic.php?f=16&t=3187

If none of these steps solves the problem, it is likely a h/w issue.

How old is this DM42?

--Bob Prosperi
10-04-2022, 04:37 AM
Post: #3
 Didier Lachieze Senior Member Posts: 1,576 Joined: Dec 2013
RE: What am I doing wrong - HP42 (DM42)
(10-03-2022 04:32 PM)rkumetz Wrote:  I have the calculator in DECM mode and SCI 10 display mode.

DECM means that your are in BASE menu and are working with integers so 6.022 E23 is not a valid operand.
Press EXIT to exit the BASE menu and divide should work.

A hint that you are in BASE mode: a long press on the divide key will show BASE÷ instead of ÷
10-04-2022, 12:22 PM
Post: #4
 rprosperi Super Moderator Posts: 5,855 Joined: Dec 2013
RE: What am I doing wrong - HP42 (DM42)
(10-04-2022 04:37 AM)Didier Lachieze Wrote:  DECM means that your are in BASE menu and are working with integers so 6.022 E23 is not a valid operand.
Press EXIT to exit the BASE menu and divide should work.

Nice subtle catch Didier, thanks very much.

--Bob Prosperi
10-04-2022, 12:38 PM
Post: #5
 rkumetz Junior Member Posts: 3 Joined: Oct 2022
RE: What am I doing wrong - HP42 (DM42)
(10-04-2022 04:37 AM)Didier Lachieze Wrote:
(10-03-2022 04:32 PM)rkumetz Wrote:  I have the calculator in DECM mode and SCI 10 display mode.

DECM means that your are in BASE menu and are working with integers so 6.022 E23 is not a valid operand.
Press EXIT to exit the BASE menu and divide should work.

A hint that you are in BASE mode: a long press on the divide key will show BASE÷ instead of ÷

I restored a clean slate yesterday and that solved the problem but I have been trying over and over to duplicate what got me to the error message. Turns out this was the problem.

Thanks!
10-04-2022, 12:42 PM
Post: #6
 rkumetz Junior Member Posts: 3 Joined: Oct 2022
Swiss Micros Support
I thought I should also mention that right before I posted here I emailed Swiss Micros.
Having had my faith in email support by so many other companies I posted here as well.

As it turns out, they replied within a few hours with some steps to get me back on track.
Unfortunately I forgot to mention to them that the BASE menu was active so they
did not have the benefit of that important snippet of information.

Now that I know that Swiss Micros has good tech support I am even happier with my purchase.
10-05-2022, 02:02 AM
Post: #7
 rprosperi Super Moderator Posts: 5,855 Joined: Dec 2013
RE: What am I doing wrong - HP42 (DM42)
(10-04-2022 12:42 PM)rkumetz Wrote:  I thought I should also mention that right before I posted here I emailed Swiss Micros.
Having had my faith in email support by so many other companies I posted here as well.

As it turns out, they replied within a few hours with some steps to get me back on track.
Unfortunately I forgot to mention to them that the BASE menu was active so they
did not have the benefit of that important snippet of information.

Now that I know that Swiss Micros has good tech support I am even happier with my purchase.

Indeed, David and Michael are both very helpful but you've also seen that the community here (as well as on the SM Forum) can often be just as helpful, and the added benefit of getting answers here is that future readers with the same issues will be able to find answers.

Welcome to the community!

--Bob Prosperi
10-05-2022, 05:07 AM
Post: #8
 Thomas Okken Senior Member Posts: 1,828 Joined: Feb 2014
RE: What am I doing wrong - HP42 (DM42)
(10-04-2022 04:37 AM)Didier Lachieze Wrote:  A hint that you are in BASE mode: a long press on the divide key will show BASE÷ instead of ÷

To make matters even more confusing: it is possible to put the calculator in BINM, OCTM, or HEXM mode without being in the BASE menu, by executing the BINM, OCTM, or HEXM functions using XEQ or using the FCN catalog. In those states, number input will be in the selected mode — although without having the A through F keys available for hexadecimal entry — but the arithmetic keys will perform their usual, non-BASE functions.

And for a final twist, observe what happens when you turn on WRAP mode (MODES -> BWRAP) and then calculate 6.022e23 ENTER 2 ÷ with the BASE menu active. In WRAP mode, the BASE functions still operate on integer inputs, but instead of complaining when the inputs are outside of the range given by WSIZE, they ignore the bits to the left of the maximum word length, and that can lead to even more surprising results if you're not aware what is going on.
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