Hello, I am seeking assistance to replace a broken key link on an Imperial type 50, we think a 1928 model.i have removed the carriage and key assembly, but not sure how to go further. I have good mechanical knowledge and have restored many vintage machines. This is the first time working on a typewriter, it belonged to my wife’s grandmother, it has not worked for many years but we would like to get it back to working order. Access to a manual or any advice appreciated. Thanks.