Reply to VCI-100 faders question

Hey guys....My left volume fader on my vci is getting really loose (having alot of play) compared to my right one. It still works but im afraid soon it will stop responding. I give this unit alot of use .....What can i do? I tightened the outside screws and that didnt help. Is there anyway to tighten from inside or do i have to replace whole thing? If i have to, where can i get replacements.

Thanks
Jay