Roland RS-09 organ 2’ slider no sound

Just got this today pretty good shape the mk 2 version with colored buttons, everything works ok accept the slider for organ 2’ no sound at all , please let me know if anyone has an idea what the problem is

Do you know if that pot is directly soldered to a circuit board, or else has a wire connected to its contacts? A wire may have broken off or a PCB contact solder point may have lifted off trace or broken off. Either may be repaired by resoldering the break. Otherwise internally the wiper contact in center of slider may not be making clean contact with the other conductor which may be a conductive carbon strip. Pot contacts can commonly get dirty or oxidized, especially if they are open construction, and can typically be cleaned with spray contact cleaner (deoxidizer) and repeated full range operations. Or also blow out any suspected dust or debris with compressed air tube.