What they said. Touching the board with your finger, or holding onto something metal (like the end of an alligator clip while probing with the other end) is a great way to find a pitch bend. Along with what computer at sea said (removing trimmers) it's also possible to, if a resistor is what keeps the pitch where it is, simply remove the resistor and replace that with a potentiometer. It's always good to try different values, as some values will be to large and cause "dead space" when in some positions.
It's a good idea to keep a good stock of different sized pots around. I keep plenty of 1M, 500K, 100K, and a bunch of lesser values ranging from 1K to 10K. With those (and a little selection of trimmers and resistors) it's always easy to find the perfect value for whatever bend you need.