In the USA, contrary to Jaka's comments, Hitec and Futaba are 100% compatable and you can safely mix eithers transmitter and recievers as long as the Hitec receivers are also negative shift (Hitec makes both positive and negative shift receivers). Your problems sound more like a bad crystal in the receiver, especially if you are sure the battery is fully charged and the switch and associated wireing is good. Have you tried plugging the battery directly into the receiver (bypassing the switch and its wires)? Remember, in dual conversion receivers, there are two crystals, the one you can change and one other. If your receiver has been in a crash or suffered severe shock from any source, either crystal could have been damaged and you can only repace the one. You would need to have the other replaced by a licensed tech or shop such as the original manufacturer or some one like Radio South, preferably the manufacturer if the second crystal is the bad one.