I have had this cooktop for 17 years and have been very happy with it until recently. When one burner is on, after several minutes, there is a popping, snapping sound and one or more of the igniters on the other burners starts sparking. I have had a repairman out three times. He has replaced the potentiometer, the spark modulator for all 4 burners. I have one burner that I can reliably use, one of the low BTU units. Before I replace this cooktop which is in excellent shape, I thoughts would see if any one has solved a similar problem. Also, if I do replace the cooktop, will the newer unit use the same vent, or will that need to be replaced as well? Thanks!