deskthority

I have bought a Model M 122-key keyboard that turned out to be dead. The controller didn't send anything to a Soarer's converter when I shorted rows and columns, and the membrane was quite oxidised.

While until yesterday I had some doubts if the membrane itself is damaged, now my doubts are no more because I have accidentally damaged it while removing the plastic rivets. One strange thing I have noticed while removing the membrane, though, is this: it only had two sheets. No middle sheet with holes in it.

Is that even normal for a membrane keyboard?

its normal for a model M

How it isolates the traces, then? Some sort of coating over traces? Where I have read about M's membranes, they always mentioned 3 layers.

Does the keyboard show any sign of use?

Without the center sheet it was probably dead from the factory.

It was used (keycap wear) and filthy (storage). Anyway, after poking Phosphorglow and Unicomp (to no avail) I ended up contacting a local shop that makes industrial flexible keyboard, and they can make a replica membrane for me.

Probably will send it to them the next week.

The membrane was intact because the rivets were in place.

jafd wrote: ↑...I ended up contacting a local shop that makes industrial flexible keyboard, and they can make a replica membrane for me.
Probably will send it to them the next week.

Any chance he could help here?
http://deskthority.net/keyboards-f2/doe ... 12422.html

I'm not in the US.

Turned out the middle sheet was there all the time, it just stuck so well that I couldn't tell it apart from the other sheet.
So, well, I think the new membrane is going to be cheaper on me.

jafd wrote: ↑Turned out the middle sheet was there all the time, it just stuck so well that I couldn't tell it apart from the other sheet.
So, well, I think the new membrane is going to be cheaper on me.

This sounds more reasonable

I suggest to check for continuity of the membrane, with the keyboard open, pressing with the finger on a crossing. Check it at the contact point with the controller.

Also, clean the contacts of the membrane with the controller. A pencil rubber will do. Always do it in the direction towards the edge of the contact. You may bend the membrane if you do it the way around.

If there is continuity, it may be the controller.