Those IBM relays are a punk when you suspect contact troubles. Pulling them out, visually looking through the relay body for debris across NO/NC contacts is time consuming. Pulling and replacing pins is a pain too. Worn NO/C contacts are hard to detect visually. And...got pins? I’ve seen pins x’d over (essentially shorting the contact) and wondered how the unit ran like it did. And you’re right about the relay base socket. Those copper male contacts on the base can fold up upon relay insertion. I’m sure Jim will plug his WizBang tester here if it handles this base.
Would the leveling card you mention fail at only a terminal floor?
