If your Sunfire True Subwoofer, Signature, MK II, MK IV or Architectural, (but not the EQ, HRS, nor Junior nor Super Junior) does not adjust volume smoothly, this potentiometer can replace the worn out original. Note that the replacement part needs to be mounted upside down, so the wires cross to match the original sequence of terminals. If you are looking for other parts for repair of a Sunfire True subwoofer, I have a capacitor kit to address common power supply issues, item 236350385203.

   REPLACEMENT STEPS: 1) Unplug the amplifier and safely discharge the 200V capacitors. They present a shock hazard until discharged.  2) Remove the old volume potentiometer.  The pins for the original potentiometer can be cut flush with the circuit board, desoldered and removed individually. Then the old potentiometer can be removed without the tedious step of completely dismounting the circuit board to which it is attached. (Otherwise, in order to remove the original potentiometer with all its pins intact, the circuit board would have to separate from the aluminum panel in order to back the shaft of the potentiometer out of the panel’s opening. The soldered pins and the adjustment shaft are at right angles, so they lock each other in place otherwise.) 3) The new potentiometer can be inserted the same way: potentiometer is fitted loosely in place first, then you connect the wires to the board, since each lead now has a flexible wire instead of a rigid row of three pins.  Note how the outer two terminals' wires (red and blue) must cross when the potentiometer faces upside down--(see the photo). I now use different color wires to make it easier to trace the path of the crossing wires. 4) Next, fully insert the potentiometer and tighten its shaft in place with the nut, keeping the potentiometer's three pins away from the circuit board. 5) Lastly, attach the new knob. 

            The new potentiometer must be mounted upside down, but it will function normally, because the three wires will be reversed to track the same position they would be in if mounted right side up. Note the profile photo that shows the depth of the pins from the face or mounting surface of the new potentiometer is less/shallower, so for the shaft to protrude sufficiently, the potentiometer cannot have its pins mount into the board. The new potentiometer has a knurled shaft, rather than a flatted-D, so a new knob that matches the shaft is included.  

            (Alternatively, the knurled shaft can be filed so that the original knob fits. I have successfully modified many other potentiometer shafts with just a minute or two of filing using a large, flat, metal file. Identify which side needs to be flattened before you begin filing, so the pointer lines up correctly. Do not just snap off one half of the knurled end. A sliver needs to remain. Only about 40% of the shaft is removed to fit a flatted-D knob.).