RE: Airtronics MX3X
I have an Airtronics MX3 sport which came with the 524 receiver. In The manual it states that 524 receiver doesnt have an bec in it. If you dont have the manual for your radio I would suggest you contact Airtronics and they can help you figure that out. I had an older xl2p receiver and I plugged a new 6 volt battery into it backwards and fried it. They fixed it for $15.00 which I thought was very reasonable. Michael J