Microwave cooking time has slowed?

[JJ]

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,

[Appliance Repair Aid]

Hi,

Model#?

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.

You where wrong ;)

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

How long does it take to boil 1 cup of water? Something below may help...

jeff. Appliance Repair Aid

[scott_z500]

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.

[ok]

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

GE Model # VM2403V 001

[Appliance Repair Aid]

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

[Jeff Wisnia]

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

[gfretwell]

Is the door closing?

[Jim Yanik]

scott [e-mail] wrote in news: [e-mail]:

They ARE vacuum tubes just like any other,and do wear out. The tube cathodes emit fewer electrons over time,as they age with usage.

[rantonrave]

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

for more information and precautions.

[Appliance Repair Aid]

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

jeff. Appliance Repair Aid

[Jeff Wisnia]

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

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

[jtees4]

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.

[IdaSpode]

I got a hammock. From eye to eye is 11'. My patio supports are about

8' wide, plus or minus. I could use an outside 4x6 support leg, and then attatch the other end to a double stud, but am not sure if the double stud would hold it, or if it would cause the stucco to flex off. I have looked and looked, and there just doesn't seem to be any place to put it where it wouldn't be in the way.

I have 2x8 rafters 24" oc, and 14 feet long. Can a hammock be hung from rafters, or would that make it fold up too much in the middle, hence folding the napping person in half? Could I use steel tubes coming down vertically from the rafters, and then use chains at an angle from the lowest point back up to the rafter?

Some ideas, please.

I'll probably just make a tube steel base for it, but that's just another thing to do and another thing to move around.

Steve

[Bob Urz]

Bob