Reply to wobbly/loose volume fader vci-100 se

hi all, I have a vci-100 se and I love it to death.. I have noticed though that my left volume fader/slider is a fair bit looser then the right one... I am no device expert so I was wondering if it would be possible to tighten this up with a screw somewhere or would i have to take bits off and tighten something else...

to help give more details the slider knob can bit slightly lifter and moved to the left/right... the one on the right hand side is form and only goes up and down..

appreciate your help.. best controller on the planet!!