[MrForbes]

Contributing to the problems Al brought up, it's a slot head screw, and hardly anyone knows that they need to hold the connector housing tightly (like with pliers, a wrench, or in a vise) when tightening the set screw. The result is that the screw was probably not as tight as it should be, which will result in a bad connection, with resulting heat cooking things and causing more problems.

I think the answer is to use crimp connectors, if you can fit them in, and have the proper crimping tool. Or make sure who ever is working on it understands how tight the set screw needs to be.

yes, we've been bit by this issue over the years....