Unsolder what's left of the pot, purchase another pot and solder it on. It should be a 5k ohm. (look for some numbers on top of the metal ring: for 5k there should be a 5 and a 3)
Last time I had My Newwish apart, the Pot is soldered to the traces of the board in 3 places.
if you point the laser lens to the LEFT and the Pot (or in your case where the Pot was) facing you...
There should be 3 solder points, 2 on the "Bottom" or 6 o'clock position, and one on the "top" or 12 o'clock position.
Now here is where we will need a bit of help......
To jumper the pot, where should a wire be strung?
Without taking mine apart and metering it, we are going to need someone's help....
I have played with mine quite a bit, and found that the APC was really the controller in this circuit.
Like I said..the whole unit was only 26 bucks...so get another on order, and then you can experiment with this one all you'd like!