I am going to re-iterate that you FULLY understand the safety when
working on a microwave oven. The ONLY technicians that I know of that
were killed while working on some equipment were working on a microwave
oven.

Even in the off state, the capacitor will hold a total charge at a
voltage high enough to immediately stop your heart. Roughly 4.5 Joules
of energy at 1.5KV is on that puppy when charged up. The lowest
defibrillator setting used in Hospitals today is 2.5 Joules!!!!!

As a result it is my own preference to never work on a microwave oven
without a high voltage probe specially made for checking the capacitor
voltage and discharging it. With the exception of the over the range
hood microwaves, very few are expensive enough to be worth much in the
way of a repair.