Hi Ross,
If that's as I suspect a Chinese cheap clone of the KB controller board, there will be a row of small preset potentiometers at the top of the board ( top as shown in the pic), there will be three together marked Min, Max and Acc, these unsurprisingly set the minimum, maximum and acceleration speeds.
If the control pot is correctly connected (see earlier in the thread) try tweaking the minimum preset first, it should be possible to stop the motor, then try the maximum preset.
The control potentiometer should have 10V DC across it, the wiper should be variable from 0 - 10V, if this isn't the case check at the P1 andP3 pins for 10V DC to determine whether it's the wiring / connectors between the PCB and the control.
A VERY IMPORTANT WARNING: The control's pins on the PCB are NOT isolated and can be at a dangerous voltage, BE CAREFUL, insulated probes and multimeter plugs are essential. If any of the control leads short to earth IT WILL DESTROY THE PCB so ensure you use a plastic-shaft pot and insulate it well, heatshrink or rubber sleeving over the pot terminals. This is true of both the clones and the genuine KB boards.
Also on the PCB are presets for motor current limit and IR compensation, if you adjust these you need to a) know what you're doing and b) measure the motor current, incorrect IR comp will cause "cogging" at low speeds, current limit set too low will reduce the motor voltage when the armature current rises beyond what it thinks is the correct max current through the motor...
I hope that helps rather than confuses!
Dave H. (the other one)
