If your GE or other Samsung-made microwave oven (usually having FCC number prefix "A3L") shuts down after a few seconds of running, then you must reset the clock and reprogram it, it's almost always a "noisy" magnetron.
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, but it's most often a failing magnetron.
I have created a test procedure to help confirm this diagnosis.
NOISY MAGNETRON TEST
(c) 2009 and posted by William E. Miller email@example.com
I the poster am the copyright holder on this and hereby grant permission to this site keep this on the FixYa Web site.
First, PLEASE do not be fooled into thinking that procedures such as this
constitute a "fix". This kind of action should only be regarded as another test method to prove that you have a noisy magnetron which must be replaced.
1. Unplug the microwave or turn off its breaker.
2. Open the door, then detach the control panel as shown in the video here
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 some 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.
If it keeps failing while the board is in the down position, you either have a very leaky magnetron or possibly another problem.
So you can then get a non-conductive plastic bag and insert a flat piece of aluminum foil into the bag and close it.
Then (with the power off) tape it over the circuit board as best you can, covering it as much as you can, making sure it does not get snagged or punctured.
Then try the oven again. Do not leave this test shield in place as a "fix". It is not safe.
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 be a "mini-manual" (tech sheet) hidden inside the unit behind the control panel or hidden on the left side behind the grille, which is very helpful when troubleshooting, testing, and locating components.
You can find links to helpful exploded view diagrams and part ordering help here
. I recommend that you bookmark that link to your favorites.
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 GE will cover the part cost, but not the cost to visit you or the labor charge to do the work.
G.E. will send you the magnetron to do it yourself. Call them at 888-239-6832.
If it is not within the magnetron warranty, you can replace the magnetron yourself by ordering it form the link above, or at least save about $75-90 by pulling the oven down from the wall and taking it to the shop yourself.
# # #