Roland Micro Cube help

Hey there all.

I'm having an issue with my Roland Micro Cube. It's been faultless all year and today it decided not to function correctly. The issue I'm having is the selection dial which allows u to change amp settings ( acoustic, Brit combo, R-Fier etc) does not seem to be working. As in I'm only getting a clean non-distorted sound out. All the other dial work just fine but I cannot get any sound change using the cosm amplifier dial. Anyone had issues with this before? I've taken amp apart and had a look but everything looks fine and I'm wondering if it's the dial that's stuffed? Picture here on link. Thanks for your help.
http://instagram.com/p/pc1RZ_Dk7g/