No Power Whirlpool RM278PXL Built In Oven Microwave Combo

[freedomfive]

Hi guys! So, today is officially the first day of taking our property maintenance and repair business full time. Well, I've been doing it full time for a while now but my husband has finally made the leap and left his other job (I'm so proud of him- it takes a lot to start up on your own like most of you have done!) I am so thankful for this forum and the help I have received here so far, and I look forward to learning more and having my experiences help others. Here is the situation I am requesting help on for a call I am going on tomorrow:

Early 1980's built in microwave/oven combo Whirlpool RM278PXL. The microwave was acting up (overheating things?) and then today no power to either the microwave or oven. Owner checked and no gfci or circuit tripped. What should I be looking at/ testing? I have looked at RepairClinic and there still are some parts available.

Thanks in advance,

Natasha

[Samurai Appliance Repair Man]

Hi Natasha,

Congrats on the Big Leap! It's a scary but exciting time-- there's nothing like being your own boss. And you actually have more job security being self-employed than you do working for The Man because you're more in control of your own destiny.

Do you have the tech sheet or wiring diagram for this unit? There has to be a thermal cutoff that's tripped and killing power to the unit. Also, have you checked the incoming power supply with a meter?

[RegUS_PatOff]

... no power to either the microwave or oven.

no power to either Oven ?

then it's a connection box OR house power problem

[NCARepair]

There should not be any cut outs to the oven portion of this combo. Check breaker for 220 volts first then the supply line behind the unit.

[freedomfive]

Hi Guys,

Thanks for the suggestions (and encouragement!)

Today will be my first time on site so I will look at the power supply and see....

Natasha

[freedomfive]

Alright...life is never what it seems When I went on site I found out that the original info I had was wrong: the oven is working just fine, it is only the microwave that is having problems. They said it started this last week: one time it really overheated water- they said the water was in the regular amount of time but when they drank it, their mouth was burnt. Then it didn't work.

When I arrived the display read "000" and the light worked when I opened the door so it obviously had power. I put in a wet dishrag and turned it on. It ran and the rag was heated. I guess it's one of those things like the symptoms always disappear at the Dr's office

So, what should I be checking?

Thanks in advance,

Natasha

[Budget Appliance Repair]

I never heard of a microwave heating too much!!!!

Probably operator error, put in a much longer time then they meant to and didn't realize it.

[Samurai Appliance Repair Man]

I never heard of a microwave heating too much!!!!

Me neither! I think they left something in there too long and, coincidentally, one of the HV components failed later. There may be no connection between the "overheating" and component failure.

Here's how to troubleshoot the microwave using the Divide and Conquer Method™ ==>

[freedomfive]

Thank you for the responses. I hadn't seen the the microwave "divide and conquer" method yet- that will be very helpful!

Thanks again,

Natasha

[NCARepair]

This microwave has a broken stirrer belt. Part #311958. Drop down the control panel and reach up to the left above the cavity. Work the belt around the pulley with one hand while keeping tension on it so it stays on then hook it to the small pulley on the blower motor. When this belt breaks you will have hot spots in the oven. Easy to see how this works if you purchase a magic light bar from your supplier. They are about $5.00.

[Budget Appliance Repair]

NCARepair, very good thought. I forgot about that, not many microwaves use a belt to turn the stirrer fan anymore. Most are turned by the air flow from the cooling fan or just have a mica wave guide cover now days.

If there is a stirrer fan in a microwave and for some reason it doesn't turn NCARepair is absolutely correct that you will have hot spots and if the item being heated happens to be just in that spot all the microwave beams hit it directly instead of being dispersed evenly around the microwave cavity

Edited June 6, 2012 by Budget Appliance Repair

[RegUS_PatOff]

Whirlpool RM278PXL c.1982

Belt # 18

click on picture

[freedomfive]

Great sleuthing- thank you for the replies! I will go ahead and order that part from RepairClinic since it costs less than the gas back and forth to the site I'll keep y'all posted...