Cambridge Azur 851A Problem! Help!!

I just sold my 851 and the buyer sent me a video of the toggle on/off switch on the back is in the "ON" position and won't stay in the "Off" position. B ut it is powered "ON". I never had a problem with it before. What could it be??It doesn't make sense.. I doesn't have any speakers hooked up to it because he says" He's in between speakers right now.????