Sounds like you have one of the newer convection units that has the inverter. With the unit running for a short time then shutting down, the problem is typically with either the inverter or the magnetron. The mag on most of these units are under warranty for 5 years. If the trouble turns out to be with the inverter, prices can vary greatly on them from 35.00 - 140.00 The question as to whether it is worth repairing is totally up to you. How much did you pay for it originally?? If you paid 400.00 and it cost you say 150.00 to fix it...is that worth it to you?? Some people don't want to spend more than 50.00 to repair a unit. Thats great if you have an 80-100.00 microwave. if however you have a more expensive convection microwave, I would consider a repair up to about half the cost of a new one, providing the rest of the unit is in great shape.
James Bennett / A.C. & M. Service
May 2007