• ** REMEMBER! **The microwave can still shock you even unplugged!!

    ALWAYS discharge the high-voltage capacitor first if you even think your hands will come close to any HIGH VOLTAGE components.

    Jeff mentions this: Anything in the high voltage ( magnetron, capacitor, diode, wires to and from ):
    ...Use a metal ( not the shiny chrome type ) screw driver with a insulated handle to short across ( touch both at the same time ) the terminals of the high voltage capacitor to discharge it.

    From Jeff's site: http://www.applianceaid.com/component-testing.php

    Jake

Jennair OTR - Works Fine But Sounds Like It Is Dying

my12by60

Premium Member
Joined
Dec 8, 2014
Messages
5
Location
United States
Model Number
JMV8000BAB
Brand
Jenn-Air
Age
More than 10 years
Our microwave is working as it always has since we built our home in the year 2000. In fact, of the set of Jennair appliances that we installed in the year 2000, the microwave is the only one that has not required even a single repair. Granted, we are not super-heavy users of the microwave, but still, 17 years is a good amount of time.

I am now hearing a loud noise during the cook cycle at times. On some cook cycles the microwave sounds fine. At other times, I hear a loud grinding noise. It almost sounds as if a bearing is failing, similar to an automotive pulley that is going bad. When I put my head under the unit during a noisy cook cycle, it does not seem as if the sound is coming from the turntable motor. I hear the sound much better when listening from the top vents, but I can't isolate the sound to the center or right side of the unit. I lean toward the sound coming from the right side.

After reading reviews of so many brand new units falling apart so quickly, I am inclined to fix our old unit if I can find still find the parts and complete the fix without electrocuting myself. I have watched a few youtubes showing how to troubleshoot a microwave safely. I have a cheap Harbor Freight multi-meter on hand and am reasonably handy.

Anybody have any ideas as to what my symptoms may be suggesting as the problem?

Is it worth trying to troubleshoot and repair this old unit, or do you recommend just buying a new unit?
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
99,892
Location
McMullen Valley, Arizona
Hi,

Rick should be here shortly, he and Jeff know microwaves inside and out.

But for know I can link you here: JMV8000BAB Jenn Air Microwave is Loud or Noisy

That link gives you a general idea of what noises could be the bad part. Growling noise would be most likely the magnetron starting to wear out. Grinding noise could be the stirrer motor.

Jake
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
33,453
Location
Murray, Utah 84107, United States
I think Jake nailed it. Sounds like the mag tube. The best way to test the components is to take the microwave down from it's installation. That way you can remove the cover and have better access to the parts and more room to work. You can still power the microwave on with the cover off for testing. The transformer, HV capacitor, diode, and mag tube make up the high voltage side of the machine. DO NOT TEST ANY HIGH VOLTAGE COMPONENTS WITH THE MICROWAVE PLUGGED IN.

With the cover off it might be easier to tell where the noise is coming from. If you still can't tell, unplug the machine and drain the capacitor. Take a long blade screwdriver and hold the tip on one of the capacitor terminals then touch the frame with the shaft of the screwdriver or use a pair of needle nose pliers and short the two capacitor terminals together. Check the resistance of the mag tube. It should be less than one ohm. It might still test good and be bad. Remove the mag tube and inspect the antenna for any burns or scorch marks

Here's how to test the other high voltage components:
C-Capacitor Test.jpgC-Diode Test.jpgC-Transformer HV.jpg

HV Connections.jpg
 

Jake

Appliance Tech - Admin
Staff member
Joined
Aug 24, 2004
Messages
99,892
Location
McMullen Valley, Arizona
Thanks Rick.:)

Jake
 

my12by60

Premium Member
Joined
Dec 8, 2014
Messages
5
Location
United States
Thanks for the help guys. I will take the unit off the wall, remove the case, plug it in and see if the noise is easily traced to a particular component. Based on the Repair Clinic link, looks like parts are somewhat scarce for this unit. The magnetron is no longer available, at least according to the link. If it is the magnetron, are substitutes available? Or is that more trouble than it is worth?
 

rickgburton

Appliance Tech - Moderator
Staff member
Joined
Jul 11, 2006
Messages
33,453
Location
Murray, Utah 84107, United States
I can most likely find you a replacement but you should price new microwaves. If the tube is bad other parts failing are usually not far behind. It might be better to invest in a new machine.
 
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