I have a KitchenAid microwave oven, model KHMS2050SSS, which failed. The normal noise level when cooking suddenly disappeared--all I can hear is the almost silent rotation of the tray. It is still heating, but at much reduced power level. I have a home warranty through American Home Shield (AHS), and they sent a technician from Sears (A&E). He tried to heat a cup of water, but stopped it when the normal noise level was not there. He then started it again and checked for radiation leaks, and found that radiation was leaking. He pulled the plug and told us not to use it. His diagnosis: "Microwave leaking radiation due to pitted waveguide." I paid a $60 deductible for the service call, and AHS has disallowed repair/replacement because "interior linings" are not covered. I have a several of questions: How does the technician know the waveguide is pitted (he didn't physically examine it)? If I understand waveguide technology (I have radar experience from the Air Force), a faulty waveguide can disburse radiation in an unintended patern. If that is true, the interior lining is not necessarily the problem. Is my assumption correct? Is this a common problem? AHS can send a different service company out to get a second opinion, but if the same conclusion is reached, I'll pay another $60 and still need a new microwave. Should I just go out and buty another microwave? I am considering dropping AHS.

Hi there,
Things that we may want to consider are, It could be that the training or the technician's company have their "safety" guidelines and procedures that they have to follow or the technician could be afraid of the leaking radiation causing trouble for him and for you.
I also believe that a faulty waveguide would disperse radiation to any direction. However it can be the cause of the radiation leaking outside. perhaps the lining he's talking about covers the entire microwave inside and not just some part of it.
If you'd ask me getting second technician out and paying that $60 without the assurance of them replacing it, I strongly recommend that you just get a new one and let this one go.
It would ensure you a working unit and more safe environment (since AHS won't replace it).
Your question about how did he know that the waveguide is pitted I don't know how he knew it but the wand he used definitely detected a radiation leakage so I think that what caused it and how it happened should be less priority now and what you should think of is to have a hazard free home.
Hope this helps!

In your question there are many difefent matters to clear out.
First What is under your AMS is not something standard but in any case if the problem for any apliance is due to an aplaince part failure they surerly not cover it. So their is not any reason to ask for a second opinion from AHS since you will definiatly pay another 60$.
So now the diagnosis of the tecnician for a pitted waveguide it sure need a special equipment to mesure the leaks and special procedures and safety mesures but it is also possible for a very experience techician who have came across to same problem to be able to regognise from the simptoms.
So our advice is to ask from the same technician an estimation of cost to replace the waveguide with new one and if any other parts needed. You should then ask from a second technician the same repair from the phone to give you an estimated cost. Then you can check the parts cost they mention with this parts diagram and price list and make a comparison. In any case you Microwave is not a cheap one to think direclty for a replacement, all you need is good and trsuted technician to replace the foulty parts. We dont advice a DIY jop since the replacement of waveguide is much more profesonal lob than just replace the mangetron. So if the full cost is at maximum 180-200$ but with guarantee then we sugest to proceed if it is higher or without gurantee then you should start thinking for a replacement.
Here is also a side with Microwave Ovens and their Hazards which can give you an idea of what is the waveguide , what it doing and how you can check for leak.