Question about Whirlpool MH1150XMQ Microwave Oven
We noticed that the oven wasn't heating things very fast. I checked the AC voltage at the outlet the oven gets its power, and I see the line voltage drop from 117 VAC to 106 VAC when the magnetron is on. I don't seem to hear any fan noise when the magnetron is on, and I recall that a fan used to be on when the magnetron was operating. If I run the oven on 20% power, the magnetron cycles on and off, and when the magnetron is off, the line voltage returns to 117 VAC.
I ran the heating test described in the repair manual hidden in the top of the oven, and for the reduced AC voltage case the oven heated 32 oz of water by more than 19 deg F in 60 sec at full power.
So, why is the oven drawing down the line voltage so much & seemingly heating food poorer than before?
LINE VOLTAGE WILL DROP IF THERE IS TOO LONG A RUN OF ELECTRICAL WIRE FROM THE SOURCE TO THE OUTLET
OR IF THE WIRING IS UNDERSIZED. THE 13 AMPS A NORMAL MICROWAVE DRAWS SHOULD NOT DROP THE VOLTAGE THAT MUCH. IF YOU HAVE A CLAMP AMP PROBE
PUT IN AROUND THE MAIN BLACK LEAD OFF THE PRIMARY
FUSE AND SEE HOW MUCH CURRENT IS BEING DRAWN WHEN THE MAG TUBE IS ENERGIZED. SHOULD NOT BE OVER 13 AMPS. IF AMS ARE O.K. SUSPECT HOUSEHOLD CIRCUIT.
Posted on Mar 28, 2008
I complement you on an exemplary report!
The drooping line voltage seems a little more than desired and you might want to try it on a different outlet, but doubtful the real problem. Microwave ovens are about the heavyist load that standard house wiring sees.
More likely the magnatron is just going bad especially if the fan hasn't been working and it has been running hot.
By the way, how old is it?
They are not too hard to replace yourself. Look on EBAY for "universal magnatron"
Hope Ya Fix it!
Posted on Jan 24, 2008
Tips for a great answer:
Feb 07, 2013 | Microwave Ovens
Feb 03, 2010 | Maytag MMV4205 Microwave Oven
Aug 11, 2009 | GE Spacemaker JVM1640SJ Microwave Oven
Jul 11, 2009 | Sharp R-510HW Microwave Oven
Jul 11, 2009 | Maytag MMV4205 Microwave Oven
Mar 25, 2009 | Sharp R-1610 Microwave Oven
Mar 06, 2009 | GE Spacemaker JVM1640SJ Microwave Oven
Oct 19, 2008 | GE Spacemaker JVM1640SJ Microwave Oven
125 people viewed this question
Usually answered in minutes!
Step 2: Please assign your manual to a product: