开云体育

Hello everyone, I have been reading on this board and not knowing the answers till I got to this post. I have been repairing commercial food equipment for 20 plus years and microwaves are part of that. What is going on here is the door interlock switch is worn out, the hook on the door latch has worn the plastic in the interlock switch and messed up the timing of the limit switches. The door interlock has three switches, primary, secondary, and the monitor. As the door opens, both primary and secondary must open before the Monitor closes. Primary and secondary are in both legs of power supplied to high voltage transformer, in this case hot and neutral. Monitor is across both legs, again hot and neutral in this case. This causes a dead short and blows the main fuse if either primary or secondary interlock switch is not open before the Monitor closes. Primary and secondary are normally open and monitor is normally closed. If the HV transformer burns and causes high current draw this usually blows the breaker for the outlet and leaves fuse in microwave fine. The reason for this is to prevent opening the door with magnetron putting out microwaves and cooking the person that opens the door or pacemaker interference. If we run into a unit that has a blown main fuse we automatically replace the door interlock switch, don't pass go just do it. The door hook slamming into the plastic of the interlock switch wears the plastic where it eventuality makes the primary and secondary not open fast enough before monitor closes and blows the extremely fast blow fuse preventing relay or limit switch contacts from welding closed. You need a new interlock switch and fuse.