My microwave oven model no.jem23k004 want heat up food and makes a lod noise

Chances are you have a shorted high voltage diode or magnetron.

Here are some links you or someone you know can use (in order given) for test help, but read the safety warnings first:

http://www.gallawa.com/microtech/diode.html
(if it is NOT shorted or burned looking, it's probably fine)

http://www.gallawa.com/microtech/mag_test.html
(continuity can be good even though mag is bad!)

The owner's manual will tell you how long your magnetron warranty is.

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 GE will cover the part cost, but not the cost to visit you or the labor charge to do the work.

If it's under magnetron warranty, GE 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, again you can find helpful exploded view diagrams and order parts by entering your full model number here.

If you prefer to arrange service by an authorized service center, GE Customer Service is here.

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