It's been a while since the modifications seen at Kaldi New Wide Roaster Modification
I've tried 2 different PWM boards and settled on one. The one at the bottom (motor governor) is the PWM board I bought 2 years ago and have been using. It turns out the knob is flimsy and even a slight touch without turning will change the level. One at the top is the latest PWM board mounted on plastic box and it behaves much better.


Mounted on the back of motor chassis (further away from the heat source).


The original PWM board shown on the old thread is now mounted elsewhere and controlling the vent fan motor.