Double check the battery's first( transmitter & receiver ),next I would open it up and look for loose wires.I'm not familiar with that particular tank,but is there other controls on the tank for gun movement,or gun fire.If so do they work like they should??
Trouble shooting is a process of elimination,and it can be a real pain trying to track down the culprit.Wish I could be more help. Good luck---BIGMIG