Kenmore Microwave Repair Help

[themovieguru]

Hello All- I have a microwave repair situation that I would really love some help in figuring out.

The Microwave: Kenmore 665.60652000 (Manufactured October 2000)

The situation is as follows:

• We recently had a water boil advisory, so I was boiling water in an assembly-line style using the microwave. I did this because the stove was taking forever and I didn't want to stand there and watch it.
• I did 13 minutes at a time on high, one after the other.
• At the end the 4th run, the microwave made a loud grinding noise for several seconds, then completely shut off. There was no light on the display, and the breaker had tripped. I reset the breaker, and the clock came back on. I did not use the microwave again for the rest of that day and night.
• The next day, I went to warm up food, and the microwave made the same grinding noise for several seconds, then turned off again. The breaker did not trip this time. Nothing I did could get any power back to the unit.

Blown Fuse?

• I did some research and saw that there was a possibility that it could be a blown fuse. I ordered a new fuse and installed it. Upon installation, the clock came back on when I plugged the unit back in. Both the internal light and range light also worked.
• When I attempted to run a test, the microwave made the same grinding sound (did not trip the breaker) and powered off. It would not come back on again.

Other Ideas?

• I found my way to a post that indicated that the thermoprotector might be at fault (part information below). This is a cheap part, but very difficult to replace because you have to take the entire unit apart.
• https://www.repairclinic.com/PartDetail/Thermoprotector/8183697/903783
• Microwave Thermoprotector 8183697
• Genuine OEM Part # 8183697
• I will certainly attempt this if I get some kind of confirmation that this is the culprit, but I have no way of knowing and don't want to proceed further without more information.
• Could it be the magnetron? Or the high voltage capacitor?

Why Bother?

• The general consensus is that microwaves are not worth repairing. I completely understand the reasons why. I know this microwave is very old.
• HOWEVER- in my research of new microwaves, I've been unable to find a unit that isn't going to fail within a couple of years and/or potentially start a fire. I have zero confidence in any unit at any price point or form factor.
• The microwave died because of something stupid I did, and not due to crappy manufacturing or a defect.
• Therefore, I really want to do whatever I can to repair this one, if it is possible.
• I would rather spend the money on parts/repair than on a new microwave because I feel this approach provides a higher chance of long-term reliability. I do not feel willing to buy units every year or so and just throw them in the garbage.

So, my big questions to the community are:

• Does anyone have any ideas regarding what component(s) could be at fault here, and how I might repair them?
• Does anyone know what that grinding noise before power off means?
• Is this unit simply unrepairable?
• I greatly appreciate any ideas or thoughts you might have on this project, and will provide any additional information, as needed.

Thank you!
 

[Vance R]

1 hour ago, themovieguru said:

Does anyone know what that grinding noise before power off means?

Was it more like a arcing sound similar to an arc welder?

[CJ Pool]

My concern on a microwave  this old is any of the parts still available? 

[CJ Pool]

First off 21 years for a microwave is outstanding.  It is unlikely you did anything to cause a premature failure of your machine.  There are a couple  of causes that could cause your noise. Knowing more about the grinding sound could help narrow the cause however. Again not many microwaves  make it past 15 years and even fewer to 20. Most microwaves only have a life of about 7 to 10 years. 

So causes are likely a high voltage component (magnetron,  HV diode,  Capacitor). All can cause your noise. Also a burned wave guide can cause noise due to arcing.

If the waveguide is the culprit a replacement can usually be handmade and clean the inside of the microwave really well.  This can normally solve an arcing issue.

If your noise was caused by a HV part the fix becomes a bit more difficult dicey. First the magnetron is no longer available and if you can find one through another source you would have to remove the cabinet cover to install it. Not a small project.  Do you know your way around a multimeter? You would need one to do the appropriate testing. Also for safety reasons I do not recommend trying to repair  HV parts in your microwave unless you have experience because of the possibility of electrical shock.  The HV Capacitor  holds a charge sufficient enough to kill a person even though the power is removed from the unit.

 

[themovieguru]

11 hours ago, CJ Pool said:

First off 21 years for a microwave is outstanding.  It is unlikely you did anything to cause a premature failure of your machine.  There are a couple  of causes that could cause your noise. Knowing more about the grinding sound could help narrow the cause however. Again not many microwaves  make it past 15 years and even fewer to 20. Most microwaves only have a life of about 7 to 10 years. 

So causes are likely a high voltage component (magnetron,  HV diode,  Capacitor). All can cause your noise. Also a burned wave guide can cause noise due to arcing.

If the waveguide is the culprit a replacement can usually be handmade and clean the inside of the microwave really well.  This can normally solve an arcing issue.

If your noise was caused by a HV part the fix becomes a bit more difficult dicey. First the magnetron is no longer available and if you can find one through another source you would have to remove the cabinet cover to install it. Not a small project.  Do you know your way around a multimeter? You would need one to do the appropriate testing. Also for safety reasons I do not recommend trying to repair  HV parts in your microwave unless you have experience because of the possibility of electrical shock.  The HV Capacitor  holds a charge sufficient enough to kill a person even though the power is removed from the unit.

 

Thanks so much for the information.

In regards to the question about the noise, the best I can describe is that it was a loud grinding noise which lasted for perhaps three seconds. I'm afraid I do not know what an arc welder sounds like. I will add that I did not smell any kind of electrical burning or other abnormal odor, nor did I see any smoke.

I do not have a multimeter, and though I have seen them in operation over the years, I would not say I know my way around one enough to be able to effectively use it. I work in tech and my experience is with computer and electronics repair. I have a rule though, which is I do not do any repair that involves soldering. That being said, I can learn and be directed to do what is necessary if there is a reasonable likelihood it would result in a successful repair.

In terms of parts, I was able to locate a new OEM magnetron and high voltage capacitor from a few parts websites and Ebay.

Is there any way to narrow this down further, or perhaps test anything? Or is the only way to get this done to throw parts at it? I've definitely been there with a lot of computer/device repairs so I get that sometimes this is the only way.

[CJ Pool]

Without a multimeter  then yes you are essentially guessing  which part is bad. As inexpensive as new units are it might be cheaper to simply replace yours. That said I would start at the HV Diode. If you could find meter you can test the diode with a 9V battery.  Remove the diode and place 1 lead on the anode end and touch the cathode end to the positive terminal on the battery. Touch the other lead of the meter to the negative  terminal of the battery. The bateTurn the meter to DC volts. You read zero. Then turn the battery around and take  the reading. In 1 direction you should get zero and in the other you should get a voltage between 5 and 7 volts. If you search Google on how to test microwave  diodes there are a ton of articles and videos that can show you how. WHATEVER YOU DO. DO NOT TOUCH TERMINALS ON THE HV CAPACITOR.  IT WILL KILL EVEN WITH THE POWER DISCONNECTED.

[themovieguru]

2 hours ago, CJ Pool said:

Without a multimeter  then yes you are essentially guessing  which part is bad. As inexpensive as new units are it might be cheaper to simply replace yours. That said I would start at the HV Diode. If you could find meter you can test the diode with a 9V battery.  Remove the diode and place 1 lead on the anode end and touch the cathode end to the positive terminal on the battery. Touch the other lead of the meter to the negative  terminal of the battery. The bateTurn the meter to DC volts. You read zero. Then turn the battery around and take  the reading. In 1 direction you should get zero and in the other you should get a voltage between 5 and 7 volts. If you search Google on how to test microwave  diodes there are a ton of articles and videos that can show you how. WHATEVER YOU DO. DO NOT TOUCH TERMINALS ON THE HV CAPACITOR.  IT WILL KILL EVEN WITH THE POWER DISCONNECTED.

Thanks so much for this information; I really appreciate it. I can see about buying a multimeter, and I do have a 9V battery. I have seen some videos about how to discharge the capacitor using insulated pliers. I'm not sure if there's a better way to do it or not. Any advice based on your experience? I think that's probably the aspect of this that concerns me the most. That and getting it down from its mounting by myself.

And I really wish modern microwaves were not such junk, because I would have no issue buying a new one with new features, etc. But unfortunately they are not and it seems exceedingly unlikely that quality will increase at any point in the future. I would rather buy parts and have the repair not work than buy a soon-to-die microwave for equivalent money. But that's just my point of view.

[GoodFerNuthin]

Did you solve this?  I had to fix my GE over-the-range microwave (2003 model) recently, and the symptoms were similar.

I found the display dead one morning, and when I was reaching in the cabinet above to check the outlet, found the top of the unit hot.  I looked inside and all the food residue had burned black.  Turns out my boys had been running it empty to use it as a timer: 20 minutes at a time(!), and had done that several times.  The 110 outlet was still live, but no clock, no function.  After checking a few parts with a multimeter, I found the 20A main fuse was blown.  I replaced that, put a cup of water in the unit, and ran it.  It ran for a few seconds, then made a groaning noise and blew the fuse again.  

The troubleshooting flow chart (in an envelope tucked behind the microwave's grill) indicated that if you replace the fuse and it blows right away, test the door switches and HV transformer.  But if it runs a few seconds then blows the fuse, test the HV capacitor.  My capacitor tested bad, so I bought another fuse and a capacitor, replaced both and it's been working like a champ since.  

I'm with you about not wanting to replace a microwave with late model junk.