As its out of warranty it might be worth opening up and checking if there’s anything obvious going on connection wise before you send it for repair. One of the guys on here recently opened up one of the silver boxes (forget if it was MD or MM) and managed to do a simple fix. Hopefully they’ll see this and jump in with advice. http://www.elektronauts.com/t/how-i-repaired-my-monomachine-mk1-pics-of-internals-included/10880
Turned out to be a loose cable connection…