Thermador smw272y won't heat at all

The switches on the first circcuit card mounted horizontally in the space above the microwave enclosure and behind the control pannel have burned to the point that they no longer engage properly to close the power to the oven heating elements. I do not know anyone who has removed the plastic covers and cleaned them to the point of working again properly and do not recommend trying that approach. The only sure solution is to replace the circuit card that has the three switches.