Hello K_2yle
I have just had the same thing happen to me twice in the last month on two new tanks I ordered.The lights on the tank would flash,but that was it.The problem in both cases was the crystal in the tank that plugs into the main board.After checking each crystal on a working tank,each one in the transmitters was OK,but the other half of each set that went into the boards was bad.Also check that the one for the transmitter ( has TX on it,and the one off the board has RX on it.)You can also check that they are the same frequancy.(Now this was on new tanks) in your case if you had been running them and this happened it could be a problem some where else.But if you have another tank that you can swap crystals i would try that first before anything else.Also push on the crystals in the radio and in the tank to make sure they are not just loose,this happened to someone else here on the forum and it was just a loose crystal.Good luck and hope its just something simple. BIGMIG--


P.S. you can buy crystals from tower hobby that will work in these radio's,(RC RED HAWK BRAND)They are around $5.00 dollars a set and shipping is like $3.99--You can order several sets and the shipping is still the same price.(hope your in the U.S. --Didn't look to see where your from,price and shipping applies here in the states)