DJQuick

I have the same problem. The air fan won’t turn off. I recently had to replace the carbon brushes in the fan motor as they had worn down. This caused a arc on the motor which blew the component on the board that controls it (triac) I also replaced the triac and all was good again. Well at least for 10 mins of running. Speed was ok and it turned off and on. But now it won’t turn off anymore. The green light goes off on the control pad but the air pump continues to run albeit at a lower speed and there is no way I can stop it. I will be replacing the triac opto isolation chip on the control board next.

I have the same problem. I have recently replaced the carbon brushes in the fan motor and the triac on the control board that controls the fan motor as that had also gone. It ran great for 10 mins and everything was fine. Speed control and on off etc. Then I went to turn the fan off and it is now just staying on. I am going to try to change the triac driven opto isolator chip next to see if that works. I would love a circuit diagram for this thing. Did you manage to fix yours if so how?