Came in and per customer, the Oven unit was showing F4 error code. removed the top unit to work on the bottom. checked switch sequence and found the microswitch wasn't engaging. also found primary and secondary latch on the same time. found the monitor switch broke off. replaced monitor switch. also adjusted the primary switch. checked magnetron, circuit pulling 17 amps. let unit get to temp and had customer use. operation okay with no error codes showing up. I cleared all of the faults.