Was my fault, this keyboard was given to me for free, and some of the palstic rivets where break, because of this some keys where not working unless some pressure was applied, initially I have no idea that was the cause so I thought that membrane edge connectors have bad connection due silver oxidation (black color) so I use a rubber to clean, I used too many pressure and some of the silver ink was "erased" so I don't continued with the other membrane, that was the first problem
, then I learn about nut bolt mod and on that moment I realized that problem was because lack of pressure by the broken plastic rivets, I ordered all to do the mod, after 3 month of wait nothing arrived so I opted for other solution, an experiment, I use a mix of acetone and ABS plastic know as ABS slurry (
https://www.matterhackers.com/news/how-to-make-abs-juice-glue-and-slurry) to remake the broken rivets... and it WORK!!! but was a partial success, this because the eroded silver ink trace on edge connector was causing problems and some keys works but then it doesn't work, but I didn't realized that and I thought that I don't used the necesary pressure when I was applying the ABS slurry, the bolts and nuts arrived.... So I remove all the ABS slurry to do the nut and bolt mod, only to see that some ABS slurry entered between two membranes, was easy to clean but some was struk over a silver ink trace and when I remove the plastic also remove part of the trace
, I used copper foil and kapton tape, that fix that problem, I assembled all and problems was still present and the rest of this history is know on the previous post...
So Folks, for general knowledge this history is about what NOT TO DO to attepmt to fix a IBM model M keyboard, it also reafirm that bolt and nut mod is the BEST to fix problems with bad plastic rivets and show how tough a IBM model M keyboard is, afther that burden it can be fixed and work again.