The trusty Mercotan Microwave (probably at least 15 years old) is failing.
Now it takes over a minute and 45 seconds to poach an egg, when until recently, 1 minute, 12 seconds were fine every time. Hot pockets, formerly done in 1:30, now take well over 2 minutes to get hot in the center. These cooking processes require different power settings, medium and high.
In the past, I thought microwave ovens either worked, or didn’t work at all. This loss of efficiency is surprising.
Any explanations? Is it an easy repair, or is it time to hie on out and purchase a new oven?
My microwave is built in to a cabinet. It appears to have a “close-out” panel to custom fit the microwave to the hole in the cabinet. How do I replace it? Are their custom panels that go around your every-day off-the-shelf microwaves or is there a special microwave for built-in applications?
No, we had a microwave that went to hell over time. It was up to over 8 minutes to cook a TV dinner where it started out at 4 about 8 years ago. I replaced it last year and the new one was rather cheap and better than the first one was originally. I tried cleaning and inspecting the first one but it just didn’t work worth a damn anymore. The loss of power took place over about a year until I got mad at it and threw it in a dumpster.
Generally, when they fail, they do fail completely as you say. But any condition which results in either less current through the magnetron, or a lower voltage across it will result in a reduction in power. The HV circuit includes a voltage doubler which consists of a capacitor and a diode in series. If the cap starts to break down, the leakage across the dielectric will reduce the current through the tube, causing a loss of power over time, for example. It may be economically repairable, but more likely that not it would be more cost effective to buy a new oven.
My guess is that the emission from the magnetron is too low. A number of things can cause this. (See Q.E.D.'s post.) If the magnetron is bad, it may be better to just buy a new oven.
Yes, they need to be designed for enclosed operation, because regular ovens have cooling fans and blocking the vents will result in premature failure due to overheating.
Is the microwave a built in? Because if it isn’t, the price of microwave ovens these days makes them a disposable item.
My sister has a built in microwave oven. My nephew’s buddy lit some taquitos on fire after he passed out. Me personally, I usually light baked potatos on fire. Are built in microwaves a standard size? I told her she should buy a spare and store it in the garage because with my nephew, this is guaranteed to happen again.
My microwave in my condo sucks big time. It actually has an analog dial, which is so retro! It takes forever to heat something. I replaced the one at my house and it made a world of difference.
I’m thinking of checking it’s efficiency. If I stick a liter of water in it, I can calculate the amount of energy it uses to raise the temperature in say, 4 minutes. I’m thinking that it takes 1 calorie to raise 1 ml 1 degree celsius, right? 1 watt = 0.238845897 calorie/second, according to some web site.
I assume that microwave oven power ratings are measured at the plug. According to some random web site, microwave ovens are 64% efficient. Looking at the Costco web site, I see that you can buy a Panasonic 1250W microwave for $89.99.
OK,
1250W * 0.64 efficiency * ((0.238845897calorie/sec)/W) / 1000cc) * 240sec = 45.85841222 degrees celsius. If my microwave doesn’t heat up a liter of water by 45 degrees celsius, than it’s not working at proper efficiency, or I could be completely mistaken.
Unfortunately, I don’t have a thermometer, so I’ll continue to wait 8 minutes for it to heat up a cup of coffee.
Dagnabbit, my microwave just broke. Well, it worked just fine to cook my broccoli, but the START button died upon presentation of a potato. Just one potato, is that too much to ask? I’m hungry. My dinner is delayed. Damn it, it must be a Monday.
My friend’s microwave has only a functional 2 and 4. He says that this is all you need. 44 seconds for a cup of coffee, 2:44 for for leftovers. Personally, I find this annoying, but it’s his house, and at least I know what the limitations of it are. I can’t seem to adjust the power rating using only the 2 and 4, so there is not the option of using this additional degree of freedom.
It may, however, be feasible to convert the space for the built-in microwave to an open shelf you could put a standard microwave on, provided you’re careful to leave plenty of clear air space for venting.
I encourage this notion because, after years of working on them, I hate built-ins with the fire of a thousand humming magnetrons.
Absolutely. I also want to clarify the statement you quoted to avoid confusion: ALL microwave ovens have cooling fans, but the ones designed for enclosed installation have the vents positioned so as to blow the exhaust air out the front or some other unobstructed direction. Regular countertop ovens typically blow the air out the rear or the side.
