M122 - two keys do not send any scancodes

feltel

21 Apr 2021, 19:05

I thought I just finished my M122 Batteship after some trouble. I screw-modded it as it was in need of it. I flashed a brand new Pro Micro to serve as a converter. Much to my surprise I found that all keys do register and send scancodes when running hid_listen but two do not. It is the center key in the cursor cluster (no problem, I wont use it anyway) and the cursor-right key. :oops:

Could this be a membrane issue? I'm unsure but a broken trace should have much more impact? My M122 is a early type one which has its membrane glued onto the back plate. Could the controller board be the issue?

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Muirium
µ

22 Apr 2021, 10:30

Here's the matrix:

Image

Having any trouble with the numpad Enter key as well? That would indicate a column is out. Otherwise, I'd look at adjusting those bolts and making sure those flippers are *physically* working correctly.

feltel

22 Apr 2021, 10:53

Ouch. A bad membrane or trace would be a bummer. If I read the matrix correct the J trace (or the corresponding part on the controller board) would be the one in question. I´ll take the board apart (again) and check this.

feltel

22 Apr 2021, 17:24

I think I found a crack in the membrane. It is in the area where the membrane connector is bent over towards the controller pcb. Looking thought the membrane towards a light source you can see the J trace is cut and another is nearly broken and it is only a matter of time till it breaks.

I should source some copper foil or something like conductive paint to try to fix the cracks. As the cracks are in the most unfavorable area of the membrane it has to be a somewhat flexible fix which "excuses" some bents.

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Muirium
µ

22 Apr 2021, 18:02

Well that sucks.

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