That board (when it is new, with the old one it is a useless operation) must be calibrated - during calibration, the position of the lower stop of the regulation is set on the potentiometer (the potentiometer turned to the maximum is always the maximum power of the motor), then during regulation and after setting the value below the lower stop, the board turns off the motor (sometimes this is used for vacuum cleaners without a switch).
So, if the board settings are messed up somehow (which is probably the case), then you must first set the absolute minimum value of the potentiometer, plug the vacuum cleaner into the socket, turn the potentiometer to the absolute maximum (you can't do it with a screwdriver, a knob - it doesn't have such a range) and then return it to the minimum and turn off the vacuum cleaner - the whole action lasts for 3-5 seconds. This is how the board is reset.
After the reset, it must be set - this is done by turning the potentiometer to the maximum (the maximum deflection of the potentiometer is also the maximum power of the vacuum cleaner), inserting a knob into it and pulling it down to the minimum that corresponds to the scale, which is drawn on the plastic on the scale vacuum cleaners (no more, no less - just the minimum). After starting the vacuum cleaner and initializing the electronics (softstart will take place and so on), everything works as it should. If not, the electronics must be reset again.
TB, December 2022
