Always shut down and disconnect the mains power before removing the front panel.
To replace the Trackball on a Hog 4 or Full Boar 4 console:
Undo the four front panel screws with a 3mm allen key (plus the two thumb screws in the armrest on the Hog 4 console) , and carefully lift up the front panel from the edge closest to you and insert into service slot.
Look undermeath the front panel and locate the cable connection that connects the Trackball to the PCB. Unplug this connection.
Unscrew the 3 allen screws that hold the Trackball to the front panel (use a 3mm allen key). You should now be able to remove the trackball from the console.
Replace with a new trackball assembly and reassemble your console by performing this procedure in reverse.