I have a Frigidaire microwave mod:# FMV156DCG. It is about 7 years old. Last week it started tuning itself off. It will run for about a min or 2 then the motor stops but the timer and light stay on. Any ideas what it wrong?

Could be magnetron failure (shorted)

From the description a major part has failed, the magnetron is suspect because it suddenly shut down in cycle, if the unit is less than 7 years old it probably has a inverter board and tends to fail, also there is the possibility the keypad control board has stopped working. The microwave in my opinion is worth getting checked out and repaired, but it will be expensive.

The unit normally draws about 13 amps of current when it's running, so it's not unusual for the wires to get warm.

A bad bottom door switch is very common in these units.

Once it's fixed, make sure no one opens the door while it's cooking. That causes premature switch failure.

Tell them to hit the "stop" pad first.

More info here:
http://031d26d.namesecurehost.com/mwd/doorsw.txt

Your model's base service manual is at our site here.

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

uplug the micro wave for the same amout of time the dector go off and see what happen if it goes off check the battery and replace them and do the same as above test to see if dector is not working properly

22 years old and you are complaining that it starts andomly, you got way more than your moneys worth for heavens sake loosen up and buy a new one. Help the economy out.

My Magic chef Microwave also starts by itself the the keyboard locks up.
We have had this unit for 4 years with no problems. I called Magic Chef and they are sending me a new brain for the unit and then someone will come to my home and repair it. NO CHARGE! I am very pleased that they are backing their product like this. God Belss America

I'm confused. If it's 6 weeks old, you can get it repaired free.

If it's 1-1/2 years old, the manufacturer will cover the part cost of the magnetron (assuming that's what's wrong) and you will have to pay for labor and any other needed parts.

Also, the subject line mentions a model LMV1630ST while your message body mentions model LMV1680BB.

For Goldstar / LG / customer service, help, call 1-800-243-0000 (M-F, 7am-8pm CT, Sat 8-5 CT) and choose the appropriate prompt from the menu or visit here.

Chances are your problem is a bad magnetron, but it may be another high voltage part.

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

Most of the time the magnetron is defective if the food is not heating up.
In some cases there is a defective low power transformer or other componenents associated with the magnetron.
I would suggest to check the owners manual under the warranty section. Sometimes the magnetron has 5 years warranty.
Good Luck.