I have had it happen before but it quit when I went to a separate BEC. I think the BEC in some of the Sabertooths just break down over time and it is only a 1AMP to begin with. Try using a receiver pack with both red wires from the esc unhooked to see if it helps. I even had a bone head Idea and overloaded my stand alone BEC and had the same thing happen again and it had me baffled till I figured out what I had done. The short story, a 20 amp Castle BEC won’t run a servonaut sound system.
