Hi and welcome along to the forum, what type of tanks did you get and what is the problem ?.im sure the knowledge on here is good enough to point you in the right direction.
Welcome dragon the knowledgeable ones will be along shortly to solve your problems
Taigen Tiger 1 full option rctank.de special edition airbrush paint IR equipped Type 90 1/24 WSN T34
Heng long leopard 2a6
Heng long panzer 4 platinum
Heng long sherman
Grantham Light Armoured Division RCTC
I picked up a panzer III where the gun didn't go up and down. I found a loose wire, then I could see the gears twich and still not move. I opened up the gear box, turned the motor over by hand once, works a treat now.
Get a multimeter, check the power is getting through first. As for the turret going round and round, must be shorting out with the lights or something else the is powered all the time. A visual check of the connection should show a wire or solder crossing over