If this isn't the best place for this, let me know, but I figured some of you who have expensive scale slopers know the answer.

I'm setting up a 5M plane that will use a separate battery for the servos and the RX. While setting things up and trying them out, I have the following:

RX powered up with a 2400mah battery
Servos powered up with a 5000mah battery
I have a plug in channel 1 of an old RC Direct 72mHz rx that I can check each wire harness and individual servo. (I also tried a Hitec SS and it didn't change anything)

Now, when I attach the signal wire of any servo to plug I get nothing.

If I hook the servo power wires up to the plug the servo functions.

What gives?

All help is appreciated.

I got the answer from my budding and excellent builder, Justin in KS. Apparantly there has to be a common ground, meaning I had to run another wired from the negative of the servo battery (the 5000mAh battery) to the plugs negative. This means the signal wire and ground wire of the plug are used, but not positive lead.

Thanks Justin. I hope this helps someone else. George

Seems like a crazy set up George. You have doubled the chance of a battery failure taking the plane down. Get a Smart Fly Power expander and plug two batteries into that, then you half then chance of a battery failure taking you out.

^ ^ ^ That's what I was going to say!

It's not for me, it's a customers plane and that's what he wanted.

I plan on using the Smart Fly on my 5.5M ASW. Thanks for the comments guys.