Jim - I believe the tech found that too much gas was being provided (excessive pressure) causing the periodic ignition of the additional propane (which created the "booming" after burner type noise). In any case, the regulator at our propane bottles was adjustable. This is an adjustment which should definitely be conducted by a qualified tech, while observing a manometer gauge hooked into the propane system at the stove unit. Some regulators are not adjustable and would require replacing in a similar situation. Good News: Problem Solved, without having to replace costly electronic boards or propane supply hardware. Hope this info helps others and thanks again to all for their input. - Steve