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geekhack Community => Keyboards => Topic started by: rainbowtrout on Sat, 31 March 2018, 07:16:48

Title: Help with Model M: strange key behavior
Post by: rainbowtrout on Sat, 31 March 2018, 07:16:48
I'm currently in the process of bolt-modding my Model M. After reassembly, I noticed two things:

1) The numpad-slash key only registers about half the time when pressed normally, or when I bottom out and apply additional force to the key.
2) While holding right-arrow and other keys such that the keyboard is limited by 2KRO (e.g. right-arrow, left-arrow, up-arrow), releasing the right-arrow key, instead of doing what it should do, instead presses numpad-6. This causes both right-arrow and numpad-6 to be stuck in DOWN until I press them again.
This problem only happens when pressing multiple keys at once, and each key works perfectly fine individually.

I can reproduce 2) with the following steps: Hold right-arrow, hold left-arrow, hold up-arrow (doesn't get pressed because of 2KRO), release right-arrow.
This occurs even with just the membrane connected to the controller (manually pushing the sheets together to register presses), so I'm confident it's not an issue with the springs.
I also tried looking for problems in the membrane with a multimeter, but I couldn't find anything strange.

Anyone have an idea of why this happens/steps to fix?


Title: Re: Help with Model M: strange key behavior
Post by: Myoth on Sat, 31 March 2018, 08:53:58
the first problem is sure loose rivets or no rivets at all, a bolt mod should fix it

about the second problem, I'm not really sure ...
Title: Re: Help with Model M: strange key behavior
Post by: fohat.digs on Sat, 31 March 2018, 09:01:07
You can tighten or loosen the bolts to "tune" the action. in general, I think looser is better than tighter.

But first, try re-seating the key stem several times, maybe rocking the keyboard forward or back to get the spring to flop one way or the other.

If the pivot plate is slightly out of place, that is, if the "ear tabs" are not seated fully in their grooves, you can sometimes press straight down with something like a toothpick and shift them laterally a millimeter or so to get them back in place.
Title: Re: Help with Model M: strange key behavior
Post by: rainbowtrout on Sat, 31 March 2018, 16:09:44
The issue with numpad-slash persisted after bolt-modding and reassembling, which is why I'm not sure the rivets were the problem.

Right-arrow still misbehaves with just the membrane, controller, and ps/2 to usb adapter, and I'm wondering which is most likely to cause this behavior.
Title: Re: Help with Model M: strange key behavior
Post by: Snowdog993 on Sat, 31 March 2018, 20:48:12
The issue with numpad-slash persisted after bolt-modding and reassembling, which is why I'm not sure the rivets were the problem.

Right-arrow still misbehaves with just the membrane, controller, and ps/2 to usb adapter, and I'm wondering which is most likely to cause this behavior.

Model M keyboards ARE 2KRO.

If there is an issue with the right arrow key not responding as a "key" or "sometimes" responding, are you pressing another key while doing this at all? Sounds to me like it may not be the keyboard at fault.

Otherwise, you might want to check the obvious. I found I had trouble with a keyboard and all it took was reseating the membrane into the controller. Sometimes the problem isn't what you think it is.