Yep, I've got a Sylvania panel from the 60's and a Federal Pacific one from the 50's at my two houses. Where does one pick up a breaker for those?
Diagnose, then replace, if necessary, IMO. Also, one of his busses could be corroding in the area of that breaker. I had that happen in the utility area of my main panel and had to get the utility to cut power so I could manufacture a new weatherhead downfeed lug on the meter connection.
Hey, Phil our posts crossed..... figure out which circuit that breaker feeds and put a load on it and compare. Also, if you have a clamp-on ammeter, put it on each of the 110V leg wires with the breaker off and see what you read. Then, flip the breaker on (no load) and compare. Then load the circuit and read again.
If it's a late 80's 200A panel, there's a good chance you can get replacement breakers. My opinion would be to get a selection of them in case others need replacing in the future. Learn from my pain
