MT4155SPB - Instructions

Unplug the microwave. Remove the Philips head and safety Torx head screws along the bottom of the sides and rear of the microwave which hold the black cover on. Lift the cover up at the rear and slide it backwards to disengage the tabs on the front top. Remove the cover. Discharge the capacitor by shorting the terminals to each other and then ground. Do this with a well insulated object and be aware there may be a pop when you do this. Keep hands, etc. on the insulated part of the object (screwdriver handle, etc). There's a lot of stored energy in that capacitor. I'd advise first checking the diode to make sure its not bad. Replace it if it is. The Magnatron is held in with a couple of screws on the top and sides. Unplug the connector and remove the screws. Remove the Magnatron. Installation is the reverse of removal.

Opened Box and Replaced Part......No Problem!

After buying the (tamper proof star bit set) it only took about 15 min. You have to take the cover off to get at the latch. I found that removing the snap wire connectors made the installation easier. I made sure to mark each one, and not to force the new latch apart to much. It sure beat paying for a service call, saved about $100.

I removed the cover using a philips screw driver and a set op tamper proof torx head allen wrench set. I inspected the latch assembly and found the door latch part broken. It was easy to remove and the new part snapped into place. Repair was finished and microwave back in service in less than five minutes. Most folks would throw their microwave away and purchase a new one, the door mechanisms are usually easy to repair and parts are available. Be careful in there because of the potential of electrocution, that is why they put the tamper proof screws in place. Next time, try to repair your appliance before you decide to throw it away, may save you some hard earned money.

Remove Oven from cabinet.Remove rear outer shell, 8 screws. Loosen two screws holding receiver end of broken component which is also a gang bar for several switches. Install new door latch by inserting extended end into gang bar and one of the two rotating pins into obvious receptacle and popping the second pin into slot provided. Refastened screws holding gang bar. Cannot go wrong, holes are manufactured into receptacle which properly aligns the component. Reinstall rear outer shell, Remount into cabinet recepticle. Very simple !

Removed the microwave unit from the kitchen built in space. 4 screws hold the perimeter cover on the four corners. Unit comes out easily after unpluging from wall.
Laid the unit on the counter and removed torx and phillips screws to remove the cover that wraps around the top and sides.
Latch bracket behind the door button had one pivot post broken. Removed the old bracket. Repositioned the new bracket by pressing it in at the plastic 'ears' on the microwave. The plastic 'ears' on the microwave unit give just slightly as the new bracket pivot posts wedge into place. Replaced the cover and put the microwave unit in the built in space.

Removed outer cover

removed lower door switch

installed new switch

Wa La!

ordered a new tray

Unplug microwave. Remove the cover(mine had six screws- including 4 special screws I was able to remove the special screws with pliers. Remove the broken latch. Then you must take out the two screws which hold plastic plate that has a bunch of wires connected to it. Otherwise you can’t install the new latch without breaking the side “axle” of the latch. Once you remove the plastic plate the new latch will snap right into place. Reinstall the plastic plate w the screws and you are good to go. Note of caution. The micro cover edges are as sharp as a knife. Use gloves!

Took microwave out of builtin cabinet with 4 screws.
Put microwave on center island and removed cover.
Tested interlock switch with volt meter and it appeared ok so I put my kit back in box and sent back.
Took out magnetron unit and replace with new part.
Put cover back on and test.
All is working and installed back in cabinet. Two weeks later all still working great.

The push button door latch had broken on my microwave. After digging into the unit-which was the hardest part, getting the shell off and getting at the control panel, I was able to see an interior latch part that had one side of plastic broken off. 40. repair piece later and I was able to plug that in, put it all back together and it works, although it does not feel that solid or that it will last a lifetime. Glad I was able to fix instead of calling a repair guy.

I took the microwave out of the cabinet compartment and placed it on the counter. I removed the torx screws from the back and the two phillips head screws from each side. I then pulled the cover back and off. I removed the broken latch piece by pushing it away from me until the outside nipple was free and then pulled the piece out. I opened the door by pushing up on the latch with a flat head screwdriver. I put the end of the new part into the area behind the latch and on top of the microswitch and pushed until the outside nipple would slide into the slot. I then replaced the cover and secured with the screws taken out initially. Done.

The power on the microwave went completely out when I went to use it, but there was no power failure for the house or neighborhood. We removed the microwave from above the oven. Took out the screws on the sides and back of the microwave and slid the top back. The line fuse was located on top unobstructed, NOT behind the button panel like some microwave models. As the appliance is over 20 years old the line fuse was quite old. It was really hard to pry it out of its holder and actually broke. I used a vacuum to suck up the dust and glass and it was easier to get out the ends once the middle broke. Popped the new line fuse in, slid the top back on, put in the screws and put the microwave back in its compartment above the stove. Good as new!! We were about to spend money on a new microwave, but thankfully I came across this site. So happy I did!!

This repair was really easy. The part that took the most time was taking it down from it's compartment above the oven and putting it back up there once repaired.

Remove outside cover of microwave.Note that there are 3 unique security screws that you will need a special screwdriver to remove. There is a YouTube video that shows how to install new part. Although this was a lot cheaper than buying a new microwave the cost of $57.00 plus shipping for this 3 inch plastic part was ridiculously expensive.

The instructions on the website were incredibly easy and I saved myself a lot of headache by using this site.

-it was built in unit - so I needed to pull the decorative grill from around the outside to remove it from the wall
- removing the back of the case involved removing phillips head screws from along the side and back of the unit. the only issue I encountered on removing screws was the fact that the "torx / star" screws could not be fit with the wrench that I had (they had a pin in the center that would not allow the wrench to fit into the star). However, a pair of pliers was handy and they were removed just easily.
- I had ordered both the high voltage diode and magnetron because I didn't know which item was the problem. I grounded the diode with two screwdrivers while wearing rubber gloves to be safe. the warnings on this did the trick as it was the only scary part of the operation.
- the diode was a little hard to spot looking at the schematics, but is is found on the lower right corner of the right side of the panel and easily pulled out and replaced. I tried the microwave again to see if it worked...and it did not. So I confirmed that the magnetron was the issue.
- removing the screws for the magnetron and putting in the replacement was a dead easy and I tried the microwave again before putting cover back on. Worked like a charm. Super easy!