One of the keys on my D50 keyboard now only returns 127 velocity. I understand this is because one of two sensors/connectors under it have gone bad in some way, but that it should be simple to fix, maybe only cleaning (I hope). After opening the synth, though, I must say that it looks like I have to remove alot of things to get under the keys. Has anyone tried this? Will the whole thing fall apart when I get to the keys?

Tom, it's tricky but not too bad. The strips are usually gray rubber with a lot of bumps on them. You need to clean the brass contacts UNDER the rubber. This is only a temporary fix - the problem WILL return. Best thing to do is order new contacts from a Roland dealer and put in a new strip. If memory serves me well - the strips cover about an octave at a time.