First post here -- although I've been lurking around for a while
I recently acquired a 1991 1391406 Model M. It was very dirty, so I spent a good 4 hours looking after it and restoring to a very good condition. Luckily it doesn't have a single scratch and the keys are perfect. Looks mint now!
I tested all the keys individually and they work perfectly well. I decided to use it for a few days and realised that the Ctrl+C combination wasn't working, which is annoying. Both keys register perfectly when pressed individually. Other combinations such as Ctrl+X, Shift+C, Alt+C also work without any issues. Combinations that don't work include Ctrl+D, Ctrl+E, Ctrl+F2, Ctrl+F3, which leads me to believe that there is something wrong with that membrane row. When Ctrl+C is pressed, only Ctrl registers and fires normally.
However, I don't want to do something as invasive as a bolt mod for now, especially because this particular one still has all its plastic rivets holding strong, which is surprising to me.
Did anyone ever deal with something similar?
