After a power outage both left xlo burners won't spark. Blue light comes on but nothing works. I have replaced one of the potentiometers (other is blocked by welded bracket) and the simmer control board. When I turned on the power after replacement, the rear xlo burner sparked continuously. Only way I could stop it is to turn off power at breaker. Now both are still not working. Process of elimination is telling me the spark ignition switches are bad or spark module? Any help is appreciated.