How to Troubleshoot & Replace Ge AP4412060 / WB27X11033 Capacitor High Voltage

Instead of wasting time troubleshooting, I purchased the 3 components suggested that could be the cause for the issue (magnetron, diode and capacitor). Replaced all 3 components and now I once again I have heat. Job was really easy except for trying to install the screws around the magnetron - kept getting sucked up by the magnet. Great website and parts arrived as quickly as advertised. 

Bought some fuses and found step by step instructions on internet to narrow problem down. Mine said diode but bought capacitor just in case. Drained charge on capacitor and replaced both. Working fine now. Finding problem took about hour fixing about 10mins. 

I had to order a small set of TT20 bits to get the security screws out of the back. I ordered them from an online retailer. Once the security screws have been removed and the Phillips screws, the cover can be lifted off and away. My cover was stuck in the front. I had to wiggle it to get it to break loose from the tongue and groove seam. I had ordered a Magnetron, a fuse, a HV Capacitor, and a Diode. It did not take that long to replace the parts. I figured if I was that committed to get into it I would replace all of the parts. It's back together and it heats like New???? I did not realize how noisy the Magnetron had become over time. Now it's quiet. For half the price of a new one, it's up and running like New! Go for it. 

First step was to make sure capacitor was discharged before touching other components.Used multimeter (VOM) to check out components, diode, capacitor, and magnetron. Ordered all three as readings were not consistent with expected. Started by replacing magnetron. Tested with cup of water. Viola microwave was heating the water. Returned the other parts. Super service. One caution is to make sure capacitor is discharged before doing any work as it contains high voltage. Safety first. 

This was much easier than I expected. First and foremost discharge the capacitor, google has the instructions. The diagnosis was also easy, really just 3 parts, the Magnetron, the Capacitor, and the Diode. With a simple multimeter measuring the resistance I was able to determine the Magnetron had shorted out and the diode was bad. I replaced all three components which fixed my issue. 

Ordered at 5pm, on my front porch by 930 the next morning. Very impressive!! Installed and working by 10:15. Would have been in shop for at least 5 days. Not sure which part was bad, Dont really care at this point. Probably magnetron but kept old parts. Might be handy some day. 

Swapped Magnetron. Pulled microwave by removing the 4 mount set screws into cabinet by opening unit door. Turned off breaker. After sliding mw out, removed top cover plate 2 screws only. Once cover removed, Magnetron clearly accessible. Take a picture of wiring. Removed insulated wiring terminals from each side(2 sides). 1 pair on magnatron, 1 pair on thermostat. A magnetized phillips screwdriver is almost required for this job to remove the 4 screws mounting the magnetron and to remount. Screwdriver should be at least 8-10 inch or longer flex type. Dismounted small button type thermostat and mounted it on the new magnatron. Reinstalled magnetron, replaced wiring, replaced cover, tested microwave before reinstalling in cabinet. 

First off this appliance is 16 years old. The replacement machine is no longer made in the color we need, also the new ones rated very poorly. After taking the appliance apart I discovered the high voltage capacitor had been leaking, probably the odor I had been noticing. I had decided in advance to replace as many parts that made sense to restore it as close as possible to its original state. Replacing the turntable motor was very easy. The magnetron, capacitor and diode was a little more time consuming but not to tricky. Be sure to use needle nose pliers with good rubber handles to discharge any stored electricity in the capacitor. Do this before before disconnecting the magnetron. You will also need a security torx bit to remove the cover, regular torx bits won’t work. It took a little longer as this appliance is built into a wall cavity. 

Replaced transformer, magnetron and capacitor. Helpful tip ......take lots of pictures on phone cam to make reassembly a piece of cake. Saved $2000 or so replacement cost 

Replaced capacitor and diode.