Sevronaut S20 ECS issue

[Actros4160]

The S20 is pretty simple, I have one on my own and used it. Is your BEC working for the 5Volt receiver supply? Measure if you have 5volt on the plug which plugs in to the receiver but careful not touch them together then the BEC is toast.
You can check that with a servo on a different channel input and see if the servo is moving if you don't feel to test that with a voltmeter.
Do have a instruction for it? If not I can send you one.

Bernd