I had a pop bumper that appeared to have its skirt get stuck on occasion thereby keeping current flowing and would blow my slow-blo fuse to the solenoid circuit. That's what I thought anyway.

I had my local pinball tech come by and take a look. We couldn't recreate the 'stuck skirt' no matter what we did. But... he noticed that the diode on the solenoid of the pop bumper (or maybe it was the diode on the pop bumper switch) was not fully terminated on one end. In fact, it went through the hole on one end but didn't appear to be fully soldered. So that would mean an intermittent connection as it rattles around during gameplay.

My question is, does it make sense that an intermittent connection of the diode on the solenoid or switch of the pop bumper would cause the slow-blo fuse to blow? Or would it instead simply cause intermittent operation of the pop bumper itself?

Again, we could find nothing wrong with the pop bumper skirt and could not make it stick ourselves. I guess I'm looking for a better understanding as to what the impact would have been of a loose diode as it relates to the slow-blo fuse and if this may have been the problem all along? If terminated properly, current flows one way through the diode, I get that. If not terminated, wouldn't it stop current from flowing at all? Say I simply removed the diode, what would happen during gameplay? How would current make its way back to the slow-blo fuse?

Thanks for the replies, appreciate learning about the theory. I'll be up in there again soon and check the diode for replacing.