Picture 1 - Remove two SMD resistors next to the MC144110 chip.
Picture 2 - Install the trim pot as shown. The low and wiper leads solder to the PCB and the high side of the pot is wired to a +V connection point with a small piece (~1.5") of wire.
Picture 3 - Pot shown soldered in place with new hookup wire going to +V.
Picture 4 - Pick a place to grab the +V. The SMD diode shown is a good spot for +V.