How to repair Channel Select button on Dave Eden 'The Metro'?

Had this amp for a while, its Dave Eden DC210 COMBO with 210Mbx 2X10 Bass Cab, the channel switch use to work but within a month of fairly frequent usage it began to get worse and worse until now were i cannot change the channel and only channel 1 works. I would like to fix this myself as i am fairly good with electronics, also the fan went which somehow caused the amp to loose 60% of its power... any ideas what that could be? I would really appriciate any help or feedback as i need my baby back! haha

Harry Thompson
April 2013