Quoted from D-Gottlieb:
It sounds like you have multiple issues throughout the machine. The springs rarely get weak, what happens is that the workings get mucked up and need cleaning. The score reels need to work correctly and reset. Going through every relay and switch is what you should try next. It is pointless to troubleshoot without first adjusting the various contacts.
+1 use the systematic approach, as per Clay's EM guide. http://www.pinrepair.com/em/index.htm