Over the years I've fixed many things, often requiring first principles, experience, reverse engineering, and yes a bit of luck here and there! I want to post some of them here, in case the processes are of interest or useful to others.
Disclaimer: I accept no responsibility for any damage or harm that may result from anyone attempting to copy anything I do or show. If anything here helps anyone to get something working again then that's all my aim is, I hate it when things don't work right!