soon as I turn on the breaker, the microwave sounds like it is running

Hi @irene46841

Here's the mini manual for the microwave that will help.

Check that you replaced the switches correctly as they are not all the same type.

The Primary and Secondary door interlock switches will both test short circuit i.e. 0.00 Ohms, when the door is closed and open circuit i.e. OL or infinite Ohms when the door is open and the Monitor switch tests open circuit when the door is closed and short circuit when the door is open.

See p.5 of the manual for their location.

Be safety aware when working inside microwave ovens. The HV capacitor can store >5000V DC for months, even if the power has been disconnected for this length of time. This amount of voltage can seriously injure you. It needs to be correctly discharged as soon as it can be accessed after the cover has been removed and before commencing any further work in the oven