Microwave cooking time has slowed?
 

We have a GE built-in microwave above the range and all of a sudden the
cooking times needed to heat food have drastically increased. Is it
possible for a microwave to gradually wear out? This unit is only 7 yrs
old. I was under the impression, they either heated or didn't, and didn't
think there was an in-between.

Anyway to check it?
Any thoughts?

Tired of 10 minute, lukewarm leftovers!

Thanks,

JJ wrote:
We have a GE built-in microwave above the range and all of a sudden
the
cooking times needed to heat food have drastically increased. Is it
possible for a microwave to gradually wear out? This unit is only 7
yrs
old. I was under the impression, they either heated or didn't, and
didn't
think there was an in-between.

Anyway to check it?
Any thoughts?

Tired of 10 minute, lukewarm leftovers!

Thanks,

Hi,

We have a GE built-in microwave above the range

Model#?

all of a sudden the
cooking times needed to heat food have drastically increased.

There are a few things that can weaken and slow down the cooking but
the magnetron itself is most common for taking longer and longer to
warm something up.

I was under the impression, they either heated or didn't, and didn't
think there was an in-between.

You where wrong ;)

Low output. Occurs as cathode emission decreases from long use.
Symptom: Reduced cooking power.

Anyway to check it?
How long does it take to boil 1 cup of water?
Something below may help...
http://an.hitchcock.org/repairfaq/sam/micfaq.htm

jeff.
Appliance Repair Aid
http://www.applianceaid.com/

It will do this when it gets dirty. Clean it out real good and even
take off the cover and see if anything needs cleaning. In so far as
magnetrons wearing out I wouldn't know.

A one cup Pyrex cup of water now takes 9:30 to boil.

GE Model # VM2403V 001

Thanks
Manufacture date of 1995.
"Appliance Repair Aid" wrote in message
oups.com...


Model#?

all of a sudden the
cooking times needed to heat food have drastically increased.

There are a few things that can weaken and slow down the cooking but
the magnetron itself is most common for taking longer and longer to
warm something up.

I was under the impression, they either heated or didn't, and didn't
think there was an in-between.

You where wrong ;)

Low output. Occurs as cathode emission decreases from long use.
Symptom: Reduced cooking power.

Anyway to check it?
How long does it take to boil 1 cup of water?
Something below may help...
http://an.hitchcock.org/repairfaq/sam/micfaq.htm

jeff.
Appliance Repair Aid
http://www.applianceaid.com/

ok wrote:
A one cup Pyrex cup of water now takes 9:30 to boil.

GE Model # VM2403V 001

Thanks
Manufacture date of 1995.

10 year old OTR would be approx 600watts, which would likely boil a cup
of water under 4-5 minutes.
Since it -will- somewhat work...certainly sounds like the mag is sour.

jeff.
Appliance Repair Aid
http://www.applianceaid.com/

Appliance Repair Aid wrote:

JJ wrote:

snipped

I was under the impression, they either heated or didn't, and didn't
think there was an in-between.


You where wrong ;)

Low output. Occurs as cathode emission decreases from long use.
Symptom: Reduced cooking power.



Hey, maybe you can jolt a magnetron cathode with a short burst of
filament overcurrent to boil off junk and revitalize the cathode surface
like we used to do with B&W CRT cathodes back in the 50s?

Remember those little autotransformer CRT "boosters" they used to sell?

Thanks for the mammaries,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

JJ wrote:

We have a GE built-in microwave above the range and all
of a sudden the cooking times needed to heat food have
drastically increased. Is it possible for a microwave
to gradually wear out? This unit is only 7 yrs old.

The maximum output of a magnetron tube drops about 1-3% a year in
average use, probably because the coating on its cathode wears out and
its permanent magnet weakens (sometimes even cracks). You can measure
the power of an oven by heating some water and measuring the amount of
temperature rise.

Fill a glass or plastic container with exactly 1 quart of cold tap
water, and measure its temperature in fahrenheit by stirring a
thermometer in it. Call this temperature T1. Set the microwave for
full power (100% power), and heat this water for exactly 60 seconds.
Immediately measure the temperature again by stirring, and call it T2.
The power in watts = 37 x (T2-T1).

For the metric version, measure temperatures in Celcius and use exactly
1 litre of water. Power = 70 x (T2-T1).

Most magnetrons are warranted for 5-10 years, probably parts only, but
someone _very_ familiar with electronics repair could change the
magnetron tube for as little as $35-50, provided it's bought from the
right source (prices vary greatly, MCM Electronics is good). For
another $25-30 the high voltage capacitor, high voltage diode, and
magnetron thermal cut-off can be replaced (worthwhile with an overhead
oven, which is hard to remove and reinstall). This work is dangerous
be cause magnetrons work at thousands of volts (capacitor can retain
voltage indefinitely after AC cord is unplugged), and an incorrectly
installed magnetron tube can let strong microwaves leak past its brass
braid gasket (can cause cataracts, even skin burns). Do not operate
the oven until its metal cover has been completely reinstalled, to
protect against an exploding capacitor or the worst of the microwave
leakage. See www.repairfaq.org for more information and precautions.

Jeffry Wisnia wrote:
like we used to do with B&W CRT cathodes back
in the 50s?

Remember those little autotransformer
CRT "boosters" they used to sell?

*I* wasn't around in the 50's :D

jeff.
Appliance Repair Aid
http://www.applianceaid.com/

Appliance Repair Aid wrote:

Jeffry Wisnia wrote:
like we used to do with B&W CRT cathodes back
in the 50s?


Remember those little autotransformer
CRT "boosters" they used to sell?


*I* wasn't around in the 50's :D

jeff.
Appliance Repair Aid
http://www.applianceaid.com/


Then you missed a great period in America's history. G

The "boosters" were just little autotransformers with a tube base plug
and a tube socket wired to them. When placed between a CRT's base and
it's socket connector they boosted the filament voltage by about 20% so
the "picture got bright" again for a few more months before the filament
finally burned out.

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"As long as there are final exams, there will be prayer in public
schools"

On Wed, 30 Mar 2005 18:19:06 GMT, "JJ" wrote:

We have a GE built-in microwave above the range and all of a sudden the
cooking times needed to heat food have drastically increased. Is it
possible for a microwave to gradually wear out? This unit is only 7 yrs
old. I was under the impression, they either heated or didn't, and didn't
think there was an in-between.

Anyway to check it?
Any thoughts?

Tired of 10 minute, lukewarm leftovers!

Thanks,

You're positive the power level is set to full? The reason I state
this is because it happened to me on a GE ...so I'm not calling you
stupid unless I include myself in that :-). Some have a defrost
button, etc. Mine did not and finding the power level setting was not
so obvious.

JJ wrote:

We have a GE built-in microwave above the range and all of a sudden the
cooking times needed to heat food have drastically increased. Is it
possible for a microwave to gradually wear out? This unit is only 7 yrs
old. I was under the impression, they either heated or didn't, and didn't
think there was an in-between.

Anyway to check it?
Any thoughts?

Tired of 10 minute, lukewarm leftovers!

Thanks,


http://an.hitchcock.org/repairfaq/REPAIR/F_micfaq5.html

Bob

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