Am I correct in saying that the BEC is a 5 volt source only, and it is used to power up the receiver ?
Therefore it's best to get it from the best source, ie, a good speed controller, and that it is fed to the centre pin of the three wire plug ? I assume then that the centre pins of all the sockets on the Receiver are joined together, so any socket will do.
The main reason for disconnecting all the other BEC lines is a clash of voltages from different sources.
Ken
Well, not quite, Ken.........
The BEC (Battery Eliminator Circuit) is usually based on a small semiconductor called a regulator. This has the voltage from the main drive battery applied across its input and ground connections, whereupon it gives forth with a lower voltage across its output and ground connections. The "spare" is dissipated as heat through the metal tab. There are a couple of capacitors in there to calm things down, and that's about it. The most useful type of regulator is a "low drop-out" type, which only requires an input voltage of about 0.5v higher than the output one. If your BEC doesn't have that then you'll need a supply of at least 2v higher than the required output. (I hope you're taking notes; there's a short written exam at the end....
). If the input voltage drops below the threshold voltage required by the regulator then the BEC stops............dead. This can cause problems unless you keep the main drive battery well charged up.
The centre connection of a three-wire system is USUALLY the battery Positive, although there are some systems which have a Negative centre pin. The White or Yellow wire is the the one which carries the signal pulses to the servos, ESCs etc so they have to be separate. It's the Red and Black pins which are common to all Rx outputs.
A speed controller doesn't have to have BEC to be any good. In my experience
that's the bit that causes the most problems, in so far as often you can't see just from looking at it whether or not an ESC has BEC fitted and, even if it is clear, you can't see whether or not it's ON or OFF. IMHO it's better to have a separate BEC unit so at least you can see it's there. That way if you don't want BEC then simply don't fit one in circuit - easier and less mind-numbing than having to pull little sockets out of plug shells to disable the thing.
You were about right about the voltage clash, though.............
FLJ