Code 34 is listed as an abnormality in the offset-boom potentiometer circuit, so I would not condemn the boom potentiometer yet. Inspect and test the offset sensor, connector and wiring first. Confirm reference voltage and sensor ground at the connector, then back-probe the signal while moving the offset through its range. The signal must sweep smoothly without dropping to zero or reference voltage. Also inspect the sensor linkage and connector terminals; another Four-System owner cleared Code 34 by cleaning and re-crimping the offset-pot connector. I would not wire the solenoids directly to keyed 12 volts because that permanently defeats the cab-interference system. Please post the machine serial number because the wiring and parts vary between PC28UU-2 versions.