radio volume knob not working

[smurf]

I've  recently purchased a 1999 royal star venture and have zero knowledge of these bikes and could not find a post about the volume knob specifically the rest of the radio works its just stuck at a low volume and the knob spins free hoping someone has dealt with this before and can give some insight 

[Marcarl]

Need to clean the working of the knob with some electronic cleaner I bet.