Oven doesn't heat. This is a 2002 Maytag electric microwave oven, model #MM5186AA. It no longer

Question

This is a 2002 Maytag electric microwave oven, model #MM5186AA. It no longer heats. The touch pad no longer beeps. After I put in the time and hit start the turn table turns and it sounds as if it is heating but the timer won't count down and the food doesn't get warm. When I set the clock it will not keep time. It will stay at the time which was set. I have checked the child safety lock and it is off. Had a repairman out who did all that I tried and then said I probably had a bad circuit board. He reccomended that I buy a new oven. What do you think?