Model M - Membranes stuck together?

[njm]

I opened up a Model M (1390120) last night in preparation for a bolt mod, and found that the membranes are quite firmly stuck to each other and to the back plate. It's almost like they were glued together, and I don't know if I could separate them from the back plate without damaging them. I don't think I really need to separate them, but just found it curious. Is it common for the membranes to be stuck to the back plate?

IMG_3404.jpg (2.96 MiB) Viewed 1804 times

[PlacaFromHell]

My Wheelwriter has te same issue, maybe all model M's with that kind of backplate have this. I took it apart just using brute force and is fine. Also some warm water should help, but if it's not necessary to do it better leave it like that. Really nasty glue by the way.

[njm]

Ah thanks, good to know. I'll leave them attached.

[clickykeyboards]

I would also recommend to leave it in place and do no harm.

I have seen the layers glued together in many of the earliest model M keyboards like the 1390120's and 1390131's from 1986. Later models from 1988 - 1999 never had this as a build feature. (I might have two or three from 1987).

Good news is that it helps to protect against the conductive traces from oxidizing and helps keeps them sealed and everything aligned as a single unit.

Bad news is that if you do need to remove and separate the three layers from the shiny rainbow plate is that you risk damaging the traces by either the physical pulling work or by any liquids used (volatile fluids, alcohols, water).

[njm]

Good news is that it helps to protect against the conductive traces from oxidizing and helps keeps them sealed and everything aligned as a single unit.

That makes sense, thanks for the advice. Interesting that they only did it on the early models. I'll definitely leave the layers attached.