Danby Microwave Ovens - Page 5 - Recent Questions, Troubleshooting & Support
Microwave stops working when heating food
Foods that are low in
density or low in moisture (such as bacon and popcorn, respectively)
can cause the magnetron to overheat.
That's because there is
not enough of either mass or moisture to absorb enough of the microwave
energy put out by the oven.
The
excess energy then reflects back to the magnetron and causes a standing
wave (like a poorly tuned transmitter antenna) and causes the magnetron
to overload and overheat.
When the mag gets too
hot, it trips
the magnetron thermostat, a protective device which rests when it cools.
If this overheating is a
persistent problem, a
stopgap is to put about 1/3 to 1/2 a cup of water in a microwave-safe
container (a Pyrex measuring cup is ideal) in a REAR CORNER
of
the microwave whenever you cook such items. This will help absorb
excess energy, but you may have to increase cooking time just a little.
And
of course I always suggest that food items be placed off-center in the
microwave, NOT in the center of the turntable, otherwise the food is
not exposed evenly enough to the microwave energy and will not heat as
efficiently as it could.
(Placing it in the
center is sort of
like stirring paint by twirling a stick in the center instead of
pulling it around in a circle in the paint can).
Such inefficient heating
wastes the energy at best, and at worst it puts a strain on the
magnetron.
If
a magnetron is repeatedly subjected to such stress, it will prematurely
fail. It will also draw excessive current, which can strain the
high-voltage transformer.
That in turn will often
lead to the
oven's drawing excessive current, resulting in a hot cord and plug, and
the fuse will blow - hopefully before the transformer or
magnetron
does!
An overheating magnetron
can be due to:
- operating
oven without cover(s) in place
- wrong
magnetron installed in oven
- an old or
otherwise failing magnetron
- cracked
magnetron magnet
- improper
power line voltage (should be 110-125VAC)
- foods low in
moisture (popcorn & bacon, e.g. - add 1/2 cup of water in rear
oven)
- failed or
inoperable cooling fan or hood vent exhaust fan
- deteriorating
foam weatherstripping seals in air ducts or on outside cover
- blocked air
vents (dust, animal nest debris, insufficient free air space behind
& around oven, etc.)
- clogged or
greasy charcoal filter or grease filter
- blocked duct
in hood vent exhaust
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