MMV6178AAW Maytag Microwave - Instructions

1. I went to the internet to find the service manual for the Maytag microwave.
2. I opened up the oven and started measuring the resistance of the diode, capacitor, transformer, and magnetron between terminals and then to ground. The transformer and magnetron were well within the resistance limits. The diode was shorted in both directions(+-). The capacitor was fully open in both directions -- high resistance.
3. I ordered the 2 parts, installed them, and ran the oven. Worked perfect first time.
4. Reinstalled oven and worked ever since (1 week so far).
5. The secret was that the transformer had a load hum. I figured the transformer was OK. The magnetron had no short between filaments and ground to filaments. The only two left were the diode and capacitor. The first two are about $200 -- almost the value of a new microwave. The $70 repair was well worth it. If the first two were still bad, then tempted to buy a new oven.

Remove top grille (2 screws), undo control panel (1 screw). Tilt down control panel, switches are on the left. There are actually three switches that are involved with the door, two horizontally mounted, one vertically mounted. This would be an EASY REPAIR, but it took me a while to figure out which of the three switches was bad, and also took a while to figure out that there is a plastic rod that inserts through the hole in the switch body. Once i figured this out went like a breeze. Lower horizontal switch was the bad one, but since the kit came with two switches i went ahead and replaced the upper horizontal one as well. IT appears that the horizontal switches are probably more likely to fail than the vertical switch based on the position of the switch and force angles. Works great now!

I looked up the #1 reason for no heat for my microwave on the site , and using my model number found that 92% of the time it was the Black Sleeve Diode. Ordered the $15 part, and installed it within 30 minutes. Most of the time was used for removing the built in microwave and removing the cover. Replaced the diode by finding it on the diagram that I printed from this site (free). Very relieved that we don't need to have our custom cabinetry re-sized to accommodate a new microwave. Thank you!

After determined the problem on one of the websites...I received the part I needed... removed the control panel and installed the new main fuse In about 15 mins!

Bought new plate.

Once I got the replacement bulb, the repair was
easy. I needed to unscrew one side of the lamp assembly and pop the new bul in.

My problem was getting the right light. The local hardware store didn't carry quite the right halogen lamp and the one I bought burned out the wires that hold the light. THis was a costly repair --- about $100. So I was delighted when Part Select had the lamp I needed. They were prompt in sending it out and I was very satisfied.

I removed the unit from the wall. Took the cover off. Set the unit on its side. It revealed the working parts. Removed the old micro switches. Put in the new oness. Presto, it worked. Very easy for me.
The parts was delivered almost before my notice they were shipped.

removed various screws on tp, bottom and back to remove cover. Thermostat is behind control panel held in with metal tabs. Just bend the tabs straight and remove, install new thermostat in reverse order.

removed the cover with a phillips screwdriver and replaced filter

1. Removed cabinet screws (10-15?). 2. Removed cabinet. 3. Removed top interlock switch which actually was not defective. The press clip connection appeared as if it had been arcing for quite some time and the corrosion created resistance sufficient to prevent the current from getting through the switch. 4. Replaced switch anyway but broke plastic retaining clip despite every effort not to do so. Reset broken clip with super glue. 5. Reassembled cabinet and appliance is in good working condition.

Problem would come and go. Found service schematic inside unit. Perform all the suggested tests. One possible solution was the primary interlock switch shown on the schematic and a check found the switch stuck. It would free up some times but would stick again in the open position. Ordered switch which was a simple plug in unit.

Removed case,
Discharged HV capacitor and removed cooling fan.
Unscrewed ground end of HV diode and unplugged from HV capacitor.
Installed new diode by reversing the order. In my case, the problem was the magnetron was bad, so I replaced it as well.

Unplug microwave! It's NOT necessary to remove microwave from above stove. Removed two Philips head screws on top front of unit to remove front grille. Removed one screw to remove control panel, letting it hang down. Found inline fuse in cabinet where line cord wires come in. Pulled out blown fuse with thumb and forefinger. Snapped in new fuse, replaced control panel and grille with the three screws. Plugged in the microwave. -Worked great! Good opportunity while grille was off to clean it and replace the charcoal filter inside the cabinet.

Pulled unit out, pried the bottom plate off the unit. Mine was not screwed in, but designed to be pried off, and then replaced. That was a surprise, but not very difficult. Unscrewed the motor, unplugged the electric connection, replaced it with new part . Replaced the bottom plate and tested the machine.

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.