IBM Model M Keys not working issue

[NeonBacon]

Hey guys,

I've got a model m 1391406 that's having some issues. the esc, tab, 1, q, a, and grave key have stopped responding. This happened once before but i revived them by mashing them repeatedly. Though today, after a move they've gone again. Anyone got any suggestions on what the issue may be? I won't be able to get the right tools to open it until tomorrow.

Thanks.

[templanet]

I have the same problem with one of my keys. I took the keycap off and can make the key activate by pressing the spring down with a pen. Also the key sounds a little different to the other keys on the board when I press it, so I figure I need to do a minor bolt or screw mod. There are instructions somewhere in the forums here for bolt or screw mods.

Here's some advice from the clickykeyboards people:

Have you tried to remove and re-seat the backspace key.  Sometimes realigning the metal buckling spring within the tube that the backspace key actuates resolves problems where a single key is misfiring.  Problems of one key not firing is usually not a PCB electronics controller board or voltage problem.

You may also want to try to remove the backspace key and replace the position with a keystem from another position.  Observe if the problem is resolved with a new keystem.  If so, the problem may be with the plastic of the backspace key and you can try to clean it, lubricate it with a light machine oil, or perhaps sandpaper the surfaces to make it smooth.

Otherwise, if the problem continues after re-seating the keystem and replacing the keystem, the problem is likely internal to the keyboard and is either electrical where the connections of the internal membrane are bad or mechanical where the buckling-spring needs to be replaced.  Either would require a bolt mod.  The process is not impossible, but the process is slightly destructive and time consuming to drill out all of the plastic melted rivets and replace with M2 x 6mm screws or bolts.

[E TwentyNine]

You don't need a bolt mod just yet.   You have a trace that's either broken or losing its connection to the controller.  All those keys are on the same trace.

Open it up and reseat the membrane connectors in the controller.  The trace in question is on the larger connector.

This thread has a picture of the matrix (of an SSK) and what the connectors look like.

https://deskthority.net/workshop-f7/model-m-matrix-teensy-t8149.html

Your trace is the third one in, so if reseating doesn't work - do it a few times - see if it has corrosion on it but don't go scrubbing it, they are delicate.

As it's an inner trace and not one on the edge I'm guessing it's not broken, but that's a possibility as well.  You'll have to inspect it if reseating doesn't work.

[NeonBacon]

You don't need a bolt mod just yet.   You have a trace that's either broken or losing its connection to the controller.  All those keys are on the same trace.

Open it up and reseat the membrane connectors in the controller.  The trace in question is on the larger connector.

This thread has a picture of the matrix (of an SSK) and what the connectors look like.

https://deskthority.net/workshop-f7/model-m-matrix-teensy-t8149.html

Your trace is the third one in, so if reseating doesn't work - do it a few times - see if it has corrosion on it but don't go scrubbing it, they are delicate.

As it's an inner trace and not one on the edge I'm guessing it's not broken, but that's a possibility as well.  You'll have to inspect it if reseating doesn't work.

Cheers for the info, I'll pop to the hrdwre store tomorrow & try the fixes.