I guess you replaced the fuse? How big were the fuses you were using? Also make sure that your throttle trim is all the way down, your throttle is all the way down, and the flip switch on the right side of the Tx is towards the back (the idle up switch). It sounds more like your unit is not arming rather than the 3 in 1 is bad. Also check that the batteries in your Tx are good, the antenna is extended and the Tx is on =)