I've been flying my Phantom 1 for a couple years with no problems. This year I charged up 4 batteries for a flight. As usual I powered up the receiver, installed a battery in the Phantom, lights went thru the powering sequence as usual. When I pulled both joysticks down to the left the propellers started turning slow and erratic. I tried 3 more batteries and the same thing, props turning slow and erratic My last flight (last October) with the Phantom was without incident, perfect flight as usual using all 4 batteries running and flying perfectly thru all 4 batteries. Can anyone help?