I wouldnt think the switch/ lack there of one would make a difference, just seems like certain rxs have some bad juju with signal strengths/voltages or something like that ( recent thread with a guy from europe who had a futaba rx that didnt like the MMM- only that particular model of rx was a known issue... ). If you've got friends with different rx by speky, or an lhs near by etc, see if you can work anything out with a different rx...