GE Microwave Making Noise with Smell

My GE microwave (JE1860SB 002) made a cracking sound and stopped working. After some research, I removed the cover and checked the fuse and it was good. I then checked the thermostat flame/sensor (known as thermal cut-off or thermal fuse on other brands) and discovered it was burned out. I replaced the thermal flame/sensor and now the unit comes on but makes a loud humming sound and has a burnt smell. The next step (according to my research) is checking the diode (cable) which is attached to the capacitor. It appears I need to discharge the capacitor before proceeding? --- BEFORE replacing the sensor, the unit had been unplugged for over one week….AFTER replacing the sensor, the unit was plugged in for about 5 minutes on Jan 25, 2018.

- What is the best/safest way to discharge the capacitor? Is an insulated screw driver or pliers needed or will a rubber handle tool work considering the time it has been unplugged?

- Should I remove the two connecting wires and diode before attempting to discharge the capacitor?

- If the diode is bad should I still check the Magnetron?

- If the diode is good, what is the next item to check/test?