whiskeyfrank hi there
May I enquire as to what make of speed controller you are using?
The other think I can only think of for the time being is; when you come to switch everything on, are you switching your transmitter on first? Followed then by your receiver, and then, your main battery? Or, if you are using BEC are you switching your main battery on.
The reason I am saying this is, a lot of speed controllers now use a PIC/or a processor and what this basically does is search for a signal - from the transmitter. If it doesnt receive a signal, it may go into a 'shut down' mode.
Dont know if that may help.
Aye
john e
bluebird