Magic Chef CMV1000B Microwave Oven - Answered Questions & Fixed issues

This sounds like a thermal protector is turning the microwave off. If I were to hazard a guess, it would be the magnetron (produces the microwaves) is overheating causing the shutdown. If the fan was not running it would create the same condition by causing the magnetron to overheat.

There are typically 2 fans in these units. The fan that cools the magnetron and then the vent fan that intakes from the top of your stove then vents the air out or away from the unit. Are the lights that shine on the top of the stove working?? Sometimes if a bulb blows violently it can blow a trace off of the back of the main circuit board and that trace may also supply power to the fan

take it to an appliance repair shop for a proper diagnosis and quote

Sounds like it is ready for the dump!
Without anymore information and diagnostics, it is not possible to diagnose further.

Sounds like the magnetron is over heating. Try putting a 4 0z cup of water in the oven along side the popcorn bag. See if this helps. Usually, the oven only runs 2 to 2.5 minutes for a bag of popcorn. You may have to experiment with the slightly different cooking time...

http://www.ehow.com/how_7614605_replace-chef-microwave-light-bulb.html Here is one link that i've found. It didn't mentioned the exact model but i hope this one helps...

The plug should be located in the small cabinet above the stove. Leave it unpluged at least for 10 minutes. Mine does it occasionally when it gets hot. I haven't had a problem since I turn the fan on when I run it.

check fuses

CONTROL PANEL OR DOOR SWITCHES

When it 'popped and died' that sounds like the high voltage capacitor shorted and blew the line fuse. If the diode shorted, it would just make a LOUD growling noise in cook mode. You need an ohm meter and you need to know how to use it. Be sure to use an insulated screwdriver to short across the two terminals on the high voltage capacitor, first, always before proceeding with any troubleshooting procedure. This sounds redundant but it is a MAJOR safety issue when working on microwave ovens. Developing this habit could save your life. If you can't reach across both of the terminals, touch the tip of the screwdriver to the metal frame or body of the microwave first and then to the terminal of the capacitor that has the diode connected to it. The diode is usually black and is either rectangular or round and one end is attached to ground on the frame or the body (chassis). Of course, the other end is connected to the high voltage capacitor. The problem could be something else but this is most likely the problem. Be sure to replace the HV cap with the same value ie; .94uF 2100 VAC.

http://www.partselect.com/microwave+replace-fuse+repair.htm

No solution but keep it unplugged until you find one. Some units can cause a fire.

the low fan relay on the circuit board is faulty

see this steps and fix it. God bless you This is where you must be able to read a wiring diagram and do some "live" checks on parts. First easy check is to make sure power is coming off your control board at the MW relay. Make sure of the wires and test here, if you have 120 volts at this point, you have ruled out a lot of parts that could be the problem. You have now ruled out any switch problems, control board problems, or a thermostat or 2.If you do not have power from that MW relay on the control board, you must trace the wiring back to see if the proper voltage is going through your switches, any thermostats, and arriving at your control board. Your wiring diagram on your sheet will show you where and what to test. Below is a general switch test troubleshooting guide. If the proper voltage is coming into your control board and you are not getting voltage at the MW relay, then you need to replace the control board. If voltage is interupted by a thermostat or switch from your testing to the control board, then replace that part.Now, testing from the MW relay on to your transformer, high voltage capacitor, magnetron, and diode. Do not do any voltage reading from the secondary side of the transformer on, this can be a deadly microwave oven repair if you do not follow directions. This can result in electrocution and the "blowing-up" of your voltmeter, only do OHM testing with the power off and the capacitor discharged. Someplace in this circuit, usually before the transformer, you will have another thermostat to test. It is usually mounted on the magnetron. Do a quick OHM test to see if it is open or closed.Now to test either the transformer, high voltage capicitor, magnetron, and diode, you must test each part separately. A good rule of thumb, if your capacitor is bad, change the diode also. Another note, if you are working on an OTR model and you have determined to be one of these "heating" circuit parts, you can not test these parts until you take the unit down. If you don't have the parts with you and you have to order them, order the magnetron, capacitor and diode and you will have a 90% chance of solving the problem. If it is an older microwave, order the thermostat also, most times you can return un-used, un-opened parts. Check with your parts supplier. This way you only have to take the unit down once.To test these parts, scroll down this page and you will see a chart with component tests. Follow the instructions to find which part(s) are defective in your microwave oven repair.

definate short as the prise is so low to replace its not worth the repaire

Why don't you return it? I think this is a common problem. We returned ours to Home Depot with no questions asked.

The problem will be a bad relay, a component that drives the relay, or a broken trace on the circuit board.

This blown trace happens a lot when the cooktop lights blow.

We regularly repair such control units for customers nationwide by mail for $39.95 postpaid in about a week with a one-year guarantee.

Feel free to contact me directly (and please remind me of your full model number) for more information & help or see our Web site.

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

William E. "Ed" Miller, AS-EET
[email protected]
http://www.microwavedisplay.com

The problem is in the magnetron the heart of the system, or the inverter board, if microwave oven is 7 years old or less.

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 would refer you to Magic Chef Customer Support.We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.