What are the symptoms of a 200 amp zinco service breaker going bad? Our lights are surging when major appliances run. PG&E (power company) came out and checked and there was not a bad neutral and connections are good. Thanks for any advice.

OK need to go over the word surge, and the symptoms. Surge would mean voltage swell, or increase in voltage, and the lights would get brighter. This can be caused by a broken neutral in a 3 wire feeder, just like the feed from the utility.

If the lights are dimming when the appliance starts, that is a voltage sag, or a decrease in voltage. This can be due to voltage drop caused by a loose or corroded connection, or contact points in a circuit breaker.

Zinsco breakers are not too popular on the east coast, at least what I have seen.

I do recall an issue with Zinsco:

Zinsco Sylvania Kearney Electrical Panel and Circuit Breaker Hazards, Failures, Inspection, Detection, Repair, Replacement - Sylvania Zinsco circuit breakers and panel hazards

There are ways of confirming bad contacts in a circuit breaker, but a service electrician that has special equipment, such as a DLRO, Digital Low Resistance Ohm-Meter, or a Milli-volt-Meter, needs to test the unit.

Would be a waste of money testing a unit that already has a known problem. Money better spent on replacing the panelboard.