My Afton Bay exhaust fan stays on high. I can not control with reostat on rear. I was testing the voltage on exhaust motor, brown wire, which controls speed. I accidentally shorted to ground causing this problem. Removed circuit board and located Triacs that control the motor. Should I start with replacing the Triacs? Or the optoisolator which controls the Triacs? Does anyone have a schematic on the old style analog circuit board? 1997. Would make troubleshooting so much easier?