What battery and connectors are you using?
Start by eliminating possibilities, it's possible something is drawing down the BEC so hard that it can't reset.
First, inspect ALL the servo leads VERY closely along their entire length. If there's any damage anywhere, fix that first. Second, check your battery connections very carefully, they should fit tightly.
When power goes out, use a voltmeter and see if the ESC is seeing any power from the battery on the B+ and B- terminals.
If all of that is good:
Unplug your servo, transponder, and fan, you should just have your ESC connected to the receiver, motor and battery. See if power still goes out and never comes back.
If the same symptoms are there, disconnect the motor and try again [keep the phase wires separated].
If everything seems good, plug in the servo and track test, if possible.
If it's good from there, add the transponder back.
If it's still good, try the fan again.
If the symptoms come back when you add a component, try a replacement, if possible.
If nothing seems to fix it, try another receiver.
Troubleshooting isn't a black art, figure out what does, and doesn't work, as methodically as possible, and you'll save time and money fixing your problem.