Off topic it is.... microwaves

burdette

Does anyone know if microwave ovens wear out? My sense is that the magnetron would wear out over time... but I don' t know.

We have an old MW.... new in like 1991... that still runs fine, but seems to take a lot of time. Don't really notice it until I do something like warm a cup of coffee at work and it is HOT, but not so hot at home after the same cook time.

Thanks.

PolkWannabie

Different wattage ?

nadams

I do believe that microwaves lose some of their power over time. The other thing is that newer 'waves are, like 1100 watts, whereas the microwave we have is about 600, i believe. :-D

wlrandall

I think they do degrade over time and the magnetrons have ben known to fail, just like any other tube. We have an ancient one here at work that is rated high wattage but like yours it takes forever to heat anything.

HBombToo

the maggie will die eventually... its just a matter of time. Can you fix a maggy??? yes if you have the tools and technology but by the time your done you could have purchased 10 ovens.

HBomb

Jstas

Like HBomb said, magnetrons do wear out. You can get them replaced but a new microwave will end up being cheaper.

The wattage difference is noticable between say 600 watts and 1,000 watts but heating an 8 oz cup of coffee to boiling point, you shouldn't see more than a 30-45 second difference. TRhe main reason is, as a microwave bombards the object it is heating, it builds up heat and movement kinda like a ball rolling down a hill. The difference in power would mean a difference in the degree of incline on the hill.

If you are noticing a 1-2 minute difference in heating times for something as simple as a cup of coffee, you can pretty much be assured that the magnetron is worn out. I would replace the microwave because worn out magnetrons can actually cause short circuits which can lead to fires. Over the years, the risk of that has been greatly reduced through better technology but it is still a possibility. Besides, old microwaves, thier radiation protection can also breakdown and may even start to leak. That ain't good. So if you have the money, replace the microwave.

weavercr

I have a 1000 watt microwave that I brought back in 1981 and its still going strong, 2 min to boil an 8 oz cup of water right from the tap.

Magetrons will die sometime, spent many years working on RADARs. They normally dont degrage in power that much, just like to die. They will drift off frequency but not enought to make a difference in microwave ovens.

Jstas

Originally posted by weavercr
Magetrons will die sometime, spent many years working on RADARs. They normally dont degrage in power that much, just like to die. They will drift off frequency but not enought to make a difference in microwave ovens.

No, the magnetron itself won't necessarily degrade but the power supply can. If the power supply starts dropping voltage, the magnetron will too. Most microwaves have integrated power supplies with the magnetrons for space and packaging purposes.

HBombToo

I agree with weaver on this 1 unless the tube springs a leak which will kill the cathode and poof... no power at all.

When we rated tubes for radars it was imperative that they not drift. Carfull design of the cavity and cathode is crucial to ensure an accurate freq over the rated life of the tube.

In uwave ovens the center freq is @ ~2.05 Ghz at whatever the rated power is. At this freq the electric fields of this rf energy is proportional to the electron valence band energy in H2o which causes motion of the electrons in this lowest energy state. That said, as movement continues friction causes the water molecule to heat up all the way through the latent heat required for boiling.

Now I'm diggen way back and have a headache!

HBomb

Jstas

I think there is a disconnect here. We aren't talking about the same thing. It's probably because, in my original post, I was being very general and simplistic about something that isn't that way at all. So, I'm done.

Just an FYI though, I'm not clueless about microwaves and magnetrons and such. I'm sitting next to a phased array of microwave antennas right now as I type this. I work with the engineers who built them on a daily basis.

HBombToo

J

I did not intend my response as an in your face thing... just sharing some of my past experience.

HBomb