KHMS2040WSS3 KitchenAid Microwave - Instructions

Followed instruction already on your website

The halogen light bulb is very tight in the socket and difficult to remove by hand. Read reviews by other customers who had the same issue and complained that they ended up breaking the bulb trying to remove it. If broken may require an on-site service technician to remove the whole assembly with additional much higher cost and time. I found wrapping some duct tape around the burned-out bulb made it easier to grip and remove the old bulb without breaking it.
Based on some You-Tube videos I watched newer models now use LED light panels which appear to solve this problem.

Put s pot under were you take the screw out.If you drop it you can get it easy

It was a bit awkward because the microwave is mounted over my stove. I had to twist around and install the bulb and then replace the cover. It was a bit uncomfortable. It took me about 10 minutes to complete.

This should be a 1 minute repair. However, there are a few issues. First, make sure you order the correct bulb. Mine is a halogen push in bulb, but the parts list showed a screw in bulb.
Remove power from the unit OR be sure that the light is turned off with the push switch.. The display will show the status as you rotate through the dim levels.
There is a single Phillips head screw holding the cover on the underside of the over stove microwave. carefully remove it. When loose the panel will drop down and you will find the old bulb in the center of the front of the opening. Remove the bulb. Now the important part. Carefully unpack the new bulb being careful to not touch the glass with your bare hands or fingers. Then insert the bulb into the socket.
If you unplugged the unit then plug it back in and push the switch to check that the new bulb works and is in the socket, then turn it back off.
Carefully lift the cover back into position and replace the screw. This is the hard part as you are working upside down and can't really see when it is lined up properly. When you have the screw back in and tight you are done. Press the light switch to enjoy your lit up stove again and put your tools away.
If you get your fingers on the glass bulb then clean it off with some rubbing alcohol and a paper towel to remove any finger oils before you put the cover back in place. Finger oils can boil with the heat of the lit bulb and cause the glass to explode. This holds true for any halogen bulb.

RATHER EASY. PHILIPS SCREWDRIVER, TORX DRIVER (FOR THE 2 SCREWS SECURING THE GEARMOTOR ITSELF), VERY SMALL SCREWDRIVER TO ASSIST IN DEPRESSING THE DETENTS ON ELECTRICAL CONNECTORS AT THE MOTOR. IF THE MICROWAVE IS ABOVE A STOVE UNIT, IT'S A GOOD IDEA TO PLACE A TOWEL DOWN ON THE STOVETOP TO CATCH ANY WAYWARD SCREW IF ONE HAPPENS TO GET AWAY. (VOICE OF EXPERIENCE)

Removal of Phillip Head screws from Top vent and Control panel. Removed Torx head screw to remove entire switch assembly. Removed three wires to switch leads. Unclipped old switch. Replaced wires and inserted New switch in to clips. Attached assembly with Torx screw. Set Control panel back into place and screwed in top screw. Replaced upper vent with 2 screws.

Removed the microwave from above the oven by loosening the two screws above the microwave. As the unit tilted outward lifted up and the whole unit came out all the time feeding the power cord through the cutout for the power cord. After it was out removed the cover and identified the capacitor and made sure it was discharged and removed and replaced the diode. tested before reinstalling and it heated up just fine. Reversed order and reinstalled . Very easy job maybe a second hand to help fish the power cord when installing and removing.

Don't waste your time with other parts stores online. Partselect sells quality parts and they arrived 2 days early. I purchase a door switch from another online store and the switch was defective.

Remove the two screws to the plastic vent strip at the top of the unit. That exposes a metal cover (upper right) held in place by two more screws. (Found that removing the screw holding the key panel in place and moving that out of the way made for more work room) Remove the metal cover. The HV diode (visible) on one end is secured to the chassis by a screw. The other end is fitted to the HV capacitor. So unscrew one end and pull the HV diode off the capacitor. The replacement fits on like the old one came off. Very simple repair. But it would be safe to short the capacitor terminals to the chassis first. Noticed that it appeared the sparking was caused by the HV diode's outer casing being worn by the asbestos covered wire next to it and laying against it. I made sure the two were not touching, before putting the covers back on. Also, the problem started with an occasional spark when the MW started. It quickly deteriorated to a full, non-stop electrical sparking. You can hear it, smell it, and see it through the top vent. You don't need to remove unit to work on it.

Replaced both filters

I measured. I leveled. I mounted hanging bracket and here's where it got tricky because you need two people to raise the microwave into position. I'd stack 2x4's In the back by the wall. I'd stackem in the front on the cabinet top then raise the back and add more. You get it front back front back until it's high enough to snag the bracket. Holes pre drilled raise it on up tighten bolts and poof you're done!! I did loosen the screws that pull the cabinets together and the bottom screw that holes the cabinet on one side. It didn't seem like it needed it the way it slipped in but maybe it slipped in because I did it. Only takes a minute. Use a minute here save an hour there. Go do it! Times a wastin!!

Take off top facing over microwave using screwdriver also protection plate for diode and capaitor. Disconnect diode from frame, bracket to capacitor then remove, disconnect wires leaving diode on capacitor for right connection, replace, rewire done.

One Phillip's screw to remove glass on bottom of unit. Pull old bulb out & insert new bulb. Replace glass & screw.

Looked up symptoms on parts select website. Ordered mag and diode. Very easy to take micro off the wall. Easily removed screws holding the skin on. Found diode. Really didn't need to replace it but since I had a new one (fairly cheap), just did so. Diode only installs one way. Can't botch it HOWEVER, MAKE SURE THE ONLY PART OF THE DIODE TO TOUCH THE GROUNDING POLE IS THE SCREW DOWN LEAD. IF THE OPPOSITE END LEAD, THAT WHICH IS THE PUSH ON TERMINAL, TOUCHES THE GROUNDING POLE, YOU'LL GET ARCHY SPARKY. The magnetron goes in very easy. Simply pay attention to how you removed it and reverse that process installing the new one. There are easy to use YouTube videos that show magnetron replacement. You can do this easily and save your microwave and $$ while doing so.