After watching a youtube video, I disassembled the front cover on the cooktop (be sure to turn off the power supply). I then switched the potentiometers on two burners. The burner that was not working now worked and the burner that did work did not. Easy to find the culprit....ordered a new potentiometer from here and though I only got regular shipping, it was actually delivered the NEXT DAY! 5 minutes, put in the new part, and all burners work. Great site, thanks for the help!