Microwave magnetron shut off after 3 second

If it consistently runs for exactly 59 seconds, and shuts off, it's probably the control panel.

If it runs approximately that length of time, you might have a defective thermal protector on the magnetron, or the magnetron is running too warm for some reason.

If you need further help, I’m available over the phone at https://www.6ya.com/expert/david_29ad5d1dd86564b0

check the high voltage section or replace magnetron

If your microwave has been worked on then possibly the nuts securing the magnetron has not been properly tightened

The thermal fuse that protects the magnetron is defective or the magnetron is getting to hot causing it to shut down, if the fan is not running cools the magnetron it will shut off.

I would say that when the microwave is switched on to cook, the magnetron heaters take about 3 seconds to get the magnetron to draw current and that would coinside with a poor connection in the mains power plug or fuse holder in the machine.
Seems logical to me.

metal cannot absorb the microwaves, the microwaves bounce around inside the oven. Eventually they reflect back to the magnetron, which is the part that produces the microwaves. The magnetron can overheat and be damaged.

you need a new magnetron and inverter board, this is an expensive repair, unit can be replaced with panasonic parts or replaced with same size panasonic unit

This is almost always due to a defective or loose magnetron causing electrical interference and disruption in the control circuit board.

Details are in their bulletin here.

If your magnetron was recently replaced, it may have loose mounting nuts or bolts or maybe the wire mesh RF gasket was not installed or got pinched.

NOISY MAGNETRON TEST (c) 2009 William E. Miller [email protected]

One way to test it is to do the following:

1. Unplug the microwave or turn off its breaker.
2. Open the door, then detach the control panel as shown in the video at http://www.microwavedisplay.com and swing it down, but without disconnecting the wires. If you have any trouble getting the grille off once the screws are removed, slide the hood vent grille to the left about 1/4", then then pull it forward. On Samsung models there are L-shaped clips that fit into a slot to hold bottom of the vent.
3. Plug the microwave back in.
4. Make sure neither you nor anyone else reaches in behind the control panel. There will exposed high-voltage connections.
5. Put a few cups worth of water in a microwave-safe container and place it inside the microwave.
6. Shut the door.
7. Run the microwave for about 1 minute or so on full power. (Time Cook > 1 > 0 > 0 > Start, e.g.)
8. If it does not fail, try it several more times.
9. When the water boils, change the water and try again.

NOTE: If your model does not have a door handle, you will need to unplug the oven and reattach the control panel to be able to open the door.

If it still does not fail, I would recommend that you put it all back together and keep using it until it fails more consistently, then repeat this test.

While a microwave should never be left running unattended under any circumstances (as your owner's manual will tell you) it's even more important when one is exhibiting a failure or any odd behavior. So play it safe and stay with it while it's running!

If you or someone you know want to replace the magnetron yourself, you will need to remove the oven from the wall.

If so, the installation instructions are very handy, and it's best to have two people since the microwave can be heavy and awkward.

You can download GE owner's manuals and installation instructions here.

There should also be a "mini-manual" hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting.



You can find helpful exploded view diagrams and order parts by entering your full model number here.

If it's within the magnetron portion of the warranty (usually 5-9 years) but out of the original full warranty (usually 1 year), then your manufacturer will cover the part cost, but not the cost to visit you or the labor charge to do the work.

Sometimes they will send you the magnetron to do it yourself. Call them at 888-239-6832.

Be persistent. You may have to speak with a supervisor.

If it is not within the magnetron warranty, you can find helpful exploded view diagrams and order parts by entering your full model number here.

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In most cases when the microwave stops @ 23 seconds it's the Magnetron which has failed, and is shorting to earth.

Either that or the magnetron isn't getting the right signal from the inverter board. It gives it 20 seconds to get the right signal or it shuts itself off.

If the digital programmer circuit / controller does not get a feedback signal from the inverter for a period of 3 seconds, the controller will stop the cook cycle.

The oven will also strop after 22 seconds if there are certain problems with the inverter or magnetron.

In most cases, this is a problem with the inverter or a bad magnetron.

Due to the lethal voltages used and produced, I do not recommend that an inexperienced person work on these.

I would recommend that you contact your nearest Panasonic-authorized servicer.

We're happy to help you and we'd appreciate your thoughtful rating of our answer.