The modification can be installed by yourself as you don´t need to solder anything.
- Just open the synth´s case with crosshead screwdriver,
- connect the potentiometer to a connector on the circuit board,
- put the potentiometer thru the corresponding hole
- bolt the pot to the case by tightening the potentiometer´s hex nuts with a 10mm key
- place the knob on the potentiometer and tighten it with a small flat screwdriver
- close the synth´s housing