Replaced all 3 door switches and Frigidaire Gallery FGMV175QFA Microwave STILL Trips Breaker When Turned On

[SouthBama]

First microwave internal fuse blew twice. Then I found door switch that was stuck. Kept pushing on it and it freed up. Worked for a month then tripped again. It kept tripping. Finally got some new switches, installed, set the clock, put a cup of water inside, set it for 20 seconds, it started and stayed on for 20 seconds. Water was warm. Yay! Unit’s fixed. Next morning put food in, set time, pushed start - just like it’s been doing - you hear unit begin to start then the breaker is tripped. 
What’s going on?

What do I check?

SouthBama

[Vance R]

Double check the interlocks for proper actuation. If switches are all good then unplug the 120vac wires to the HV transformer. Make sure they are not touching or near anything or each other. They try a test cycle to see if the fuse holds.