It says Manufactured April 2010
Serial # TR 0 16 11163
Power to magnetron
Unplug microwave oven or disconnect power.
After 40 seconds, check to see whether this solves the problem.
If problem persists, you will need to order and replace the relay control board. its part # XXXXX and is very expensive. around $380.00 you can order this @ http://www.searspartsdirect.com/partsdirect/part-numbe r/Kitchenaid-Parts/Microwave-Parts/W10403040/0022/664/Model-KHMS2050SSS2/0593/0123370?keySuffixId=NA&pathTaken=partSearch&pathRender=modelComponent&documentCompId=W1203016&diagramPageId=00001&productTypeId=x&searchModelNumber=KHMS2050SSS2&subCompDesc=Control%20board%20parts&brandDesc=KITCHENAID&modelDesc=MICROWAVE-HOOD-COMBINATION&blt=11&shdMod= its part # XXXXX on this digram, hope this helps, thanks , Bryan
Didn't help. I'll call the appliance store in the morning. It's less than 2 yrs. old.