HP 41C TALL KEYS repairing questions

[aurelio]

Hi all, I've a 41C which needs to be restored.

When I bought it on TAS was defective: the internals were dirty and there was a principle of corrosion on the PCB, the block was completely damaged and also the zebra connector. I found both the spares (thanks to Diego and thanks to Dave).

I cleaned all the internals and replaced the faulty parts and reassembled the calculator and it worked, at least for a week..........altough:

a) the toggle "ON/USER" key was lazy, I mean that was necessary on the ON/OFF side to keep it pressed for a while to work
b) the ENTER key was broken (the hinge), but anyway working

I decided to keep it "as is", thinking that at least it works, but today, when I plugged in the batteries the calculator didn't wake up, Tried also with another pack (rechargeable): the same result.
Opened it and checked. externally the PCB seems ok both the viewable sides (main and keyboard), tighted properly the four screws while reassembling (there are no broken posts), so that I think the problem could be a bad contact in the toggle, finally gone.

Now I would like to disassemble the keyboard and check better, a chanche to reach and repair (or replace) the enter key too.

May you tell me if to remove the keyboard needs to cut just the plastic rivets (unfortunately a lot) and how may I restore it (glue?); then i ask if somebody has a enter key for replacing or knows where may I buy it; on TAS were for sale month ago but I think there aren't now.