Reply to VMS4.1 upfader issue!

so I've had my 4.1 for quite a while now and i love it, its a tank! but i ran into a problem with my channel 1's upfader at a gig recently, upon testing it, I discovered that the fader feels loose and it won't adjust volume when i move it both in line and analog settings. My question is, is the fader itself actually broken or do i just need to clean the inside of the fader?