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Forum Index : Microcontroller and PC projects : CMM2: Caps Lock and Scroll Lock lockup keyboard (not a bug)

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PeteCotton

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Joined: 13/08/2020
Location: Canada
Posts: 628

Posted: 10:33pm 24 Mar 2026

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I've got a weird one.

I'm in the process of making a custom case for one of my CMM2's and I found the (almost) perfect keyboard for the vibe I'm going for.

https://www.amazon.ca/MageGee-Mechanical-Keyboard-Backlit-Computer/dp/B0CP9CK5TK/ref=sr_1_9

But it's got a really weird issue. I checked, and the keyboard works fine on a PC.
But when connected to my CMM2, whenever I press the Caps Lock or Scroll Lock keys on the keyboard, the keyboard stops responding (the CMM2 is running fine - just not getting key presses). Plugging the keyboard out and in gets it working again.

Both of those keys have LEDs (on the keyboard itself) to show their status, I wonder if the keyboard is just on the hairy edge of power draw, and those LEDs push it over?

Note: I'm not looking to report this as a bug with the hardware or firmware. I have lots of other keyboards that all run absolutely fine with the CMM2s. This is very much a quirk of this keyboard. I just thought it was interesting.

My solution is that I'm going to remove those keys, and when I design my case, it will have a plastic cover over those areas. I never use Caps Lock or Scroll Lock - so no great loss, and now that I think about, it kind of adds to the retro feel of the case. Heck I might also pull the Windows keys

matherp
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Joined: 11/12/2012
Location: United Kingdom
Posts: 11215

Posted: 10:37pm 24 Mar 2026

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This is a known issue with some keyboards. Check OPTION USBKEYBOARD in the manual

PeteCotton

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Joined: 13/08/2020
Location: Canada
Posts: 628

Posted: 10:49pm 24 Mar 2026

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Oh Wow! Thank you Peter. I had no idea - and yes - that fixed the problem right away.

I was happy enough to live with it - but once again you guys are waaaaay ahead of me!

PilotPirx

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Joined: 03/11/2020
Location: Germany
Posts: 125

Posted: 11:07am 25 Mar 2026

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I'd be interested in seeing your custom case. Please post a picture of the final result.

PeteCotton

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Joined: 13/08/2020
Location: Canada
Posts: 628

Posted: 07:25pm 26 Mar 2026

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PilotPirx said I'd be interested in seeing your custom case. Please post a picture of the final result.

Oh - I definitely will.

My 3D printing knowledge has improved massively since my first case design.

This one is going to be a bit crazy. It's for a specific development project - two CMM2's in the one case. Two displays (one large, one small), and "hopefully" switchable keyboard and mouse to flick between the two.

ville56
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Joined: 08/06/2022
Location: Austria
Posts: 450

Posted: 08:23pm 26 Mar 2026

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matherp said ... Check OPTION USBKEYBOARD in the manual

Is there a different manual, other than the one included in the final release? In may manual there is no OPTION USBKEYBOARD ...

73 de OE1HGA, Gerald

PeteCotton

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Joined: 13/08/2020
Location: Canada
Posts: 628

Posted: 08:44pm 26 Mar 2026

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ville56 said

matherp said ... Check OPTION USBKEYBOARD in the manual

Is there a different manual, other than the one included in the final release? In may manual there is no OPTION USBKEYBOARD ...

There's a thread here about the manual for the latest revison.
https://www.thebackshed.com/forum/ViewTopic.php?FID=16&TID=18468

Note: you probably also want to grab the latest firmware version as well from here:
https://www.thebackshed.com/forum/ViewTopic.php?FID=16&TID=18467

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