JNM 1855 Microwave oven is 3-1/2 years old. I heard a strange sound (muffled popping noise) when I hit the cook button yesterday. The unit and control panel work fine however; the microwave will not heat the food. Any suggestions?

Sounds like the inverter (power supply for cooking) or the magnatron which does the work----neither are cheap parts.

see for the turn table obstacle of any screw or something else.

replace the door hooks and door release button.
if this is broken the switch will not close very well, and NOT start the microwave.

God bless you

Hi,
Here is a tip that will help you to figure out what is wrong with yourMicrowave Oven....

Microwave Oven Basic Troubleshooting Tips

heatman101 ;
'';

If the sound is a bit like angry bees but muffled, then the magnetron is on its way out.
Sorry.

Hi,
Here is a tip that will help you to figure out what is wrong with yourMicrowave Oven....

Microwave Oven Basic Troubleshooting Tips

heatman101
hjdhjd

We just had the same problem - spark, loud noise, and then dead. At first I replaced the ceramic fuse and the same thing happened immediately. A local appliance store tested the transformer and found it was "bad." I purchased a used transformer from the store for about $35. I installed both of these myself with little effort.

Spacemaker XL 1400 worked for 7 years.Yesterday, no more heat. Also plastic door damaged.
will try Panasonic or something commercial

It could be a loose fan.

I would say the high voltage diode blew.

If you or a friend decide to look into it, we have critical safety and disassembly information at our site, linked here on Fixya: http://tinyurl.com/yzjozk

You can get Sharp parts from Tritronics at http://www.wehaveparts.com

If it's not the high voltage diode, reply back for further help.