YKHMS1850SW1 KitchenAid Microwave - Instructions

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.

screwed in new bulb

Removed the three screws and replaced the with the new vent.

I removed the broken tray and ring-turn and replaced it with the new
Service was fantastic, parts were ordered one day and received the next

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.

Washed the glass tray and put in the microwave oven. Easy..

Used a philips head screwdriver to remove one screw holding the light cover. Pulled out the old bulb and inserted the new one. Replaced the cover.

Removed turntable
Place support ring in track
Place turntable on support ring.
Easy, peasy!

Unscrew lens and direct access to surface light cavity. Removed old light bulbs and replaced with new bulbs. Reassembled lens cover and turned lights on successfully. Took less than ten minutes.

Husband replaced the bulb

Replaced the supports and rack.

Spouse just screwed in the new bulb and reinstalled the light cover plate with the two screws. Took under a minute. Works great.

The part is held in place with two screws. A poor design for sure. The replacement part is a direct fit once the two screws are removed. Reuse the same screws, don't order new ones.

Repair took kess than 5 munutes.. Align plastic guides for the Screws and using a Philips screwdriver commence to tightening same .

I ordered another one and placed it inside the microwave. It works and fits perfectly. I received the order exactly as scheduled.