Microwave door latch question.

[fotoobscura]

Hi. I have a Panasonic "Genius" 1300W microwave that has two door levers that snap into the microwave. One of the two broke for some reason when closing the door one day. I glued the piece exactly back into place yet for some reason the safety mechanism of the microwave still thinks the two latches aren't locked in (or one latch doesn't exist, perhaps). The microwave lights up but doesn't go on and then shuts off.

There really isn't anything else to do that I can tell and am wondering if anyone has any suggestions on how to get my microwave working again. I've tried unplugging the microwave under the assumption that perhaps it was stuck on a safety mode but that didn't seem to work. Unfortunately I no longer have the manual so not sure what else to do..

Any ideas? I don't want to go in the direction of defeating the mechanism, of course.

Thanks

[fotoobscura]

Hi. I have a Panasonic "Genius" 1300W microwave that has two door levers that snap into the microwave. One of the two broke for some reason when closing the door one day. I glued the piece exactly back into place yet for some reason the safety mechanism of the microwave still thinks the two latches aren't locked in (or one latch doesn't exist, perhaps). The microwave lights up but doesn't go on and then shuts off.

There really isn't anything else to do that I can tell and am wondering if anyone has any suggestions on how to get my microwave working again. I've tried unplugging the microwave under the assumption that perhaps it was stuck on a safety mode but that didn't seem to work. Unfortunately I no longer have the manual so not sure what else to do..

Any ideas? I don't want to go in the direction of defeating the mechanism, of course.

Thanks

[Malcolm Hoar]

There is usually a little microswitch located somewhere in and around that catch. They're typically adjustable by loosening a screw or two, sliding into the right place, and retightening. The adjustment is usually pretty critical -- the microswitch needs to be in the right position to within some fraction of a millimeter.

If you can locate that microswitch and gain sufficient access it will likely be quite easy to adjust by someone who is reasonably adept with electrical and mechanical devices.

[terry]

A warning. Be very careful who works on your microwave. They are essentially a powerful microwave transmitter (up to 1000 watts) inside a metal box. With lethal DC voltages up to 5000 volts and the ability to radiate energy, it can just as easily cook your hand as a piece of meat! Even though this is a discussion about a door latch strongly recommend that the only type of person who should work on it be an electronic transmitter technician. Also m.wave ovens are so cheap (and hate to say this in view our throw- away society) it might be best and safest to get a new one and ditch the old. Be careful; microwave ovens have sometimes been described as one of the most dangerous household appliances.

[HeyBub]

"Voltage" is not "lethal;" it's "amps." Tasers run up to 200,000 volts. What is hazardous about the voltage in a microwave (or a TV for that matter) is the reaction when you get shocked. You're liable to drop the sucker on your foot.

A microwave cannot cook your hand because YOU'D MOVE YOUR HAND when it got hot! A slab of meat can't ooze out of the way. Same principle involved in trying to microwave an ant (can't be done).

Phooey.

Safe, but not sane.

Described by those who've never had an episode with an electric can opener, a cheap electrical outlet, or a wringer washer.

[Dave Martindale]

No, the electrical hazard is that there's a step-up transformer in there that is designed to deliver about 1 kW to the magnetron at a couple of thousand volts. There's also a charged HV capacitor in there. There's plenty of energy to cause electrical burns, or stop your heart if the current path happens to pass through your chest.

The major danger is electrical, not microwave RF. However, having said that, an open microwave source is a good way to develop cataracts. Your eyes are more sensitive to heating than the rest of your body (no blood flow to carry away heat from the cornea or lens) and don't have much in the way of nerve endings to warn you there's a problem.

It's quite difficult to kill yourself with any of these. An operating microwave with the cover off just requires touching the wrong place to kill you.

Dave

[Dave Martindale]

Your "exact" gluing job probably isn't exact enough. There's a microswitch in the door latch that has to close to enable the high voltage, and your repaired lever isn't quite pressing it in the way it expects.

The right way to fix this is to replace the door lever with an unbroken part, either from the manufacturer or from another scrapped oven.

Failing that, there might be some range of adjustment in the microswitch mount inside the oven (though the several I've worked on did not have such an adjustment). Read the warnings about working inside microwave ovens at

before starting.

Dave

[HeyBub]

Okay, 500 milliamps is sufficient to cause death. That means one should turn OFF the device before working on it.

Right. "At the macroscopic level, it is demonstrated that exposure to a few mW at 1 GHz for over 36 h affects the optical function of the lens. Most importantly, self-recovery occurs if the exposure is interrupted."

Then don't operate the microwave (or can opener or electrical outlet or wringer washer) with the cover off. Duh!

[Dave Martindale]

1) The references I find say 50 mA is sufficient to cause heart fibrillation. It's fatal if you don't have someone else around to revive you via CPR. 2) After turning off the device, remember to discharge the high voltage capacitor that may still be charged. 3) If the original poster is trying to align a door switch, he isn't going to be putting the outer cover back on the oven between tests. So he'll be operating the oven, with high voltage applied, with the outer cover off. Knowing where the dangers are is appropriate.

That talks about a few mW. But the magnetron output is over 1000 W when the oven is operating - that's about a million times more power. Unpleasant things can happen faster at that power level.

Easier said than done when you're repairing the innards of one. Also, remember the capacitor that's still charged after the power is turned off.

Dave