Model M 122 smell?

[Avi_]

Hi everyone.

I recently purchased 3 keyboards, IBM Model M 122, terminal, years 1987, 1988, 1989. They were in bad condition, which was expected, and two of them needed bolt mods. Even before I disassembled them I noticed the smell, but after I disassembled the membrane... Well, the blankets smell of rubber, very strongly. Noticeable even outside the room where I worked. Now when the keyboards are assembled back again, the smell is softer, but still immediately obvious when I open the box with these keyboards.

This was the first time I was doing this kind of repair. Are all Model Ms 122 smell so bad? I searched for this a bit, but pages that contain both "smell" and "model M" are very rare. What if I remove the blankets completely? Apparently this should make the keyboards more clicky, but the blankets were put there for a reason.

[suicidal_orange]

Is this the sound dampening layer beneath the PCB?  If so it can be replaced by something less smelly, look at threads/guides on bolt modding and you should find some ideas what to use

[Avi_]

There is no PCB layer in this keyboard (except for the controller), I think you meant to say beneath the barrel frame. Yes, it's the black rubber mat between the barrel frame and the membrane. If it's only for sound dampening, I'd just remove it. But if it protects the membrane from direct impact of the buckling springs, it makes sense to find a replacement.

[fohat.digs]

If it's only for sound dampening, I'd just remove it. But if it protects the membrane from direct impact of the buckling springs, it makes sense to find a replacement.

I don't think that it is there for sound at all. It cushions the impact of the pivot plate ("flipper") coming down and is also an electrical insulator.

At the minimum you might cut a piece of PVC (I would think that it should be at least 3 mil) for the quickest and cheapest solution, but if you order from Unicomp you will get the new thin white latex blanket ("mat" is something different in Unicomp lingo) and that is an upgrade, in my opinion.

And the mat is not against the barrel frame, it is between the metal back plate and the bottom mylar membrane.

[Avi_]

And the mat is not against the barrel frame, it is between the metal back plate and the bottom mylar membrane.

Oh man, you're right! I assembled it incorrectly. Hence the smell: when the blanket is between the back plate and membrane, it's almost not exposed, but when it's between barrel frame and membrane, the smell reeks through the barrels.

[Avi_]

And the mat is not against the barrel frame, it is between the metal back plate and the bottom mylar membrane.

I was confused, how did I mess it up and assembled incorrectly. And searched for more information. No, I was right in the first place, the mat is between the barrel frame and membrane, not between metal back plate and membrane. Take a look at this video: https://youtu.be/L54UK5NiG5U?t=170. He removes the back plate together with the membrane at about 2:53.

So the question remains, how safe it is to remove it completely.

[fohat.digs]

Yep, I was wrong. I haven't been inside a Model M in a couple of years.