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DM-15L current draw problem
12-28-2015, 06:35 PM (This post was last modified: 12-28-2015 11:10 PM by Katie Wasserman.)
Post: #1
DM-15L current draw problem
I have a DM-15L board -- the one with the bad buttons -- and decided to measure the current draw on it. It's quite low except when a button is held down, then it's 10mA. But even worse is that it's still 10mA when the calculator is turned off! So if you have a button that is being pressed down when the calculator is in a bag, pocket, whatever, you'll deplete the CR2032 in short order.

Can someone confirm if the newer boards have the same high current draw when a key is held down.

-katie

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12-30-2015, 01:27 AM
Post: #2
RE: DM-15L current draw problem
Yep. I had a replacement board and it shows 11mA when any key is pressed, whether on or off.

Thanks for the heads-up - I'll be careful to make sure it isn't squashed when in my bag.
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12-30-2015, 06:06 PM (This post was last modified: 12-30-2015 06:07 PM by Harald.)
Post: #3
RE: DM-15L current draw problem
(12-28-2015 06:35 PM)Katie Wasserman Wrote:  I have a DM-15L board -- the one with the bad buttons -- and decided to measure the current draw on it. It's quite low except when a button is held down, then it's 10mA. But even worse is that it's still 10mA when the calculator is turned off! So if you have a button that is being pressed down when the calculator is in a bag, pocket, whatever, you'll deplete the CR2032 in short order.

Can someone confirm if the newer boards have the same high current draw when a key is held down.
Hm, I wonder if there is a software fix for that. I would assume there are no external pull up/down resistors on the board. So it shouldn't be too difficiult to change the configuration of the internal ones in sleep mode. But maybe the "ON" key isn't treated differently and is an issue?
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12-30-2015, 06:37 PM
Post: #4
RE: DM-15L current draw problem
I wonder if the ID card-sized calculator variants have the same problem.

Greetings,

Matthias


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12-30-2015, 07:57 PM
Post: #5
RE: DM-15L current draw problem
Just checked my DM41 unit. There is a small increase when keys are pressed in off state, but only 50uA. A minor problem compared to described behavior of L variants (cannot check for myself due to calculator hobby budget screams no no no at the moment) as additional current draw is so low and foil keys are hard to press even incidentally.



(12-30-2015 06:37 PM)matthiaspaul Wrote:  I wonder if the ID card-sized calculator variants have the same problem.

Greetings,

Matthias
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02-04-2016, 09:10 PM
Post: #6
RE: DM-15L current draw problem
I asked Mr. Steinmann on this issue. He told me that it was solved in the latest version.
@Katie Wasserman / @BruceH: Did you use the latest firmware (V16) on the machines?

Regards
Bernd
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02-05-2016, 12:58 AM
Post: #7
RE: DM-15L current draw problem
(02-04-2016 09:10 PM)Bernd Grubert Wrote:  I asked Mr. Steinmann on this issue. He told me that it was solved in the latest version.
@Katie Wasserman / @BruceH: Did you use the latest firmware (V16) on the machines?

Regards
Bernd
Bernd,
Could you ask Mr. Steinmann if he is aware of any key scanning issue in the firmware? Refer to the following thread:
http://www.hpmuseum.org/forum/thread-5621.html
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02-05-2016, 07:42 AM
Post: #8
RE: DM-15L current draw problem
(02-04-2016 09:10 PM)Bernd Grubert Wrote:  I asked Mr. Steinmann on this issue. He told me that it was solved in the latest version.
@Katie Wasserman / @BruceH: Did you use the latest firmware (V16) on the machines?

Regards
Bernd

Yes, my tests were done with firmware V16 installed, I'm perplexed.

-katie

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02-05-2016, 07:48 AM
Post: #9
RE: DM-15L current draw problem
(02-05-2016 12:58 AM)Steve Simpkin Wrote:  Could you ask Mr. Steinmann if he is aware of any key scanning issue in the firmware?

I did already. Smile
See post #9 of the thread:
http://www.hpmuseum.org/forum/thread-5621.html
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02-05-2016, 07:51 AM
Post: #10
RE: DM-15L current draw problem
(02-05-2016 07:42 AM)Katie Wasserman Wrote:  Yes, my tests were done with firmware V16 installed, I'm perplexed.

I will inform Mr. Steinmann about this.
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02-05-2016, 09:27 AM
Post: #11
RE: DM-15L current draw problem
(02-05-2016 07:48 AM)Bernd Grubert Wrote:  
(02-05-2016 12:58 AM)Steve Simpkin Wrote:  Could you ask Mr. Steinmann if he is aware of any key scanning issue in the firmware?

I did already. Smile
See post #9 of the thread:
http://www.hpmuseum.org/forum/thread-5621.html

Oops, I missed thatSmile
Thank you Bernd.
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02-05-2016, 08:29 PM
Post: #12
RE: DM-15L current draw problem
Please see this thread for solution of the problem.
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