Question about Microwave Ovens
I have a Quasar microwave oven, a model # YMQ9994XW manufactured in August of 1984. The serial number for this oven is NM42140099.
When I plug the unit into a wall electrical outlet, the venting fan runs at top speed and will not shut off until I unplug the unit from the wall outlet. The touchpad has no effect in either shutting the fan off completely, or even slowing the fan down. It appears that I may have damaged a switch as I was attempting to remove the back panel to the unit, and that this switch definitely has something to do with the operation of the fan. When I pull the leads from the switch and connect the two leads together directly, the fan does indeed operate when I plug it in to the wall outlet.
I went to a local repair business to try to replace the switch, only to have the lady behind the counter say that this switch is actually some kind of a thermostat, and that the part is no longer available. She let me rummage around a small box of similar thermostats pulled from other microwaves and let me take a couple home free of charge, but I am unsure of how this part actually functions in my microwave, or if indeed this really is the problem. I have tested the continuity of my own switch/thermostat, and several switches/thermostats in the box, and all of them pass electricity through the contacts.
I also require an electrical schematic drawing or photo of some kind showing which lead from the transformer goes to what contact in the back of the oven. My girlfriend was monkeying around with it and pulled the leads going from the transformer to the oven before I had a chance to label them correctly.
ANY HELP PROVIDED WILL BE GREATLY APPRECIATED.
Hopefully the hood / vent fan was always on when boiling on the stove top.
Otherwise moisture can get into and damage the keypad or control circuit board.
That may be the problem.
If this is a convection model, it may have a bad thermistor (not to be confused with a thermostat).
The full model has three more digits, in case you need more help and want to post that.
If you or a friend decide to look into it, we have *critical* safety, disassembly, and troubleshooting info at our site, and our link is at our listing here on FixYa: http://tinyurl.com/yzjozk
You can usually find an exploded view by entering your full model number here: http://www3.sears.com (the 3 is correct)
Posted on Dec 07, 2007
FIRST ,,MICROWAVE OVENS ARE REALLY SAFTY MINDED AND THATS A GOOD THING....THERE ARE USUALLY THREE DOOR SWITHCES NEXT THE KEYBOARD--THE ONE ON TOP AND THE ONE ON BOTTOM ARE PRIMARY AND SECONDARY SWITCHES,,YOUR PROBLEM SOUNDS LIKE ONE OF THESE IS NOT MAKING CONNECTION..YOU MIGHT BE ABLE TO PRESS 'DOWN" WITH A LITTLE PRESSURE ON THE DOOR AFTER CLOSING TO SEE IF THE FAN WILL START,,,IF YOU NOTICE --THERE ARE 2 LATCHES(HOOKS) COMING OUT OF THE DOOR,,WHEN THE DOOR IS CLOSED,THOSE LATCHES ARE SPRING LOADED AND MAKE CONTACT ON THOSE SAFTY SWITCHES....THIS IS NOT A CUSTOMER REPAIR--MICRO'S ARE JUST TO DANGEROUS WHEN YOU TAKE THE COVER OFF--IF THIS DOES BRING THE FAN BACK ON--YOU GOT A BAD DOOR SWITCH AND SHOULD BE A REASONABLE REPAIR
THE OTHER SOLUTION STILL WOULD BE A CONNECTION PROBLEM ON THE KEYBOARD ITSELF-THE WIRES JUST PLUG ON THE CIRCUIT BOARD BEHIND THE KEYBOARD---STILL A EASY REPAIR--GOOD LUCK TUNICA
Posted on Oct 30, 2008
You can look for parts here on FixYa,
good luck hunting, I have the same prob, with my Sharp convection M/ wave. I have been looking for 3 yrs. now and it only a 1982. Good luck DFD
Posted on Apr 15, 2009
We see (and repair) this
a lot. The problem is on the control panel, which
we regularly repair nationwide by mail for $39.95 postpaid in about a
At our Web site, you can get details of our service, plus we have a video available showing how to remove a typical over the range control panel assembly in under 5 minutes.
This light failure often occurs when a bulb goes out and the filament shorts, or when the bulbs are removed or installed without first unplugging the oven from the power line. Either can cause such a failure on the controller.
The lights fan can be inoperable or stuck on or no bright, too. Sometimes this will similarly affect the exhaust fan operation, too.
Feel free to contact me directly (and please remind me of your full model number from the tag on the unit) for more information & help.
We're happy to help you with free advice and we'd appreciate your thoughtful rating of our answer.
William E. Miller, AS-EET
Posted on May 22, 2009
you need to remove the cover and after it operates and shuts down(CAREFULLY) feel the magnetron tube sides (BE EXTREMELY CAREFUL<HI_VOLTAGE ON TUBE FROM CAPACITOR) still, then if its not too warm there is a small temp sensor held by 2 screws on the side of the tube and they can go bad and shut off current to the tube,the tube will run warm, but should never run HOT,if its hot its defective
Posted on Oct 28, 2009
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