Punch in 1 min. to heat coffee. It counts down to 40, 41, or 42 and stops. I push start button again and microwave runs for 13 or 14 seconds and will kick off again. Pushing start button 3 or 4 times, the run time gets less and less. Until, it is only on one second--and then on and immediately off. These symptoms have repeated several times over last week, so I thought I would ask. Thanks Keith