The loud pop does usually indicate a bad rectifier. Make sure to 1. Turn off power to the microwave first and 2. discharge the capacitor before attempting any repairs.

- Replacement rectifier

Actually, it's a fairly simple job, as long as the safety rules are followed re: disconnecting the power and discharging the capacitor. But, if you don't feel comfortable working on a microwave, please don't. Getting shocked from a high voltage capacitor could mean serious heart problems or even death.

Rectifier is number 1 on this diagram and capacitor is number 2, right behind the control panel.

Here is a page that among other things shows how to discharge a capacitor. It's a long page and has lots of info on it, so I would suggest doing a search for the phrase How To Discharge The High Voltage Capacitor (click Control and F for search while on that page).

Thanks understood the hole. Now does the cap need to be discharged before taking a ohm reading? Didn't see any holes in the diode, but they dont give you a lot of area for working.

Didn't see the link at the bottom. Got it. Thanks