I've been rebuilding a 3DR Y6 DIY. Flew a first flight yesterday and everything was performing great.

Goal:

• My next project is to get the Tarot 3D gimbal up and running.

Summary:

• I wired in a BEC/voltage regulator to power the Tarot gimbal, and all my 3DR 20Amp ESCs get super hot sitting still. What am I doing wrong?

Details:

• 4S (so 13v to 16.5v) lipo battery.
• Using the 3DR power module to supply power to my pixhawk
• I was connecting all three wires (ground, positive, signal) from the ESCs to the 3DR Power Distribution Board (PDB). The ESCs all have 5V/2Amp BECs 
• I'm using a dimension engineering DE-SWADJ 10W step down adjustable switching regulator as my BEC.
• I built a harness that takes the power leads (20awg black and red wires) from the PDB.
  • positive is connected to VIN pin on the BEC
  • ground is connected to GND pin on the BEC AND GND on the connector leading to the Tarot
  • VOUT on the BEC is connected to the positive 
• With the above setup, with the battery plugged in and the DE-SWADJ installed, all six of my ESCs would get hot 'just sitting there.' No throttle to the motors, unarmed, only power draw is the Pixhawk pulling power from the 3DR power module
• I removed all of the ESC signal/BEC wires from the PDB (so the ESCs are getting power directly from the battery, but the ESCs aren't wired into the circuit) and one of the ESCs still gets super hot, but the other 5 stay cool.
• One ESC still gets hot, even with the signal/BEC wires disconnected.

Questions:

1. Is my overall circuit/connection wired incorrectly?
2. If my circuit is bad, is there a really easy/foolproof setup to get 12v power to my gimbal?
3. Anything fundamentally wrong with having the 3DR power module (which is a BEC of sorts), 6 ESCs with BECs, AND this dimension engineering voltage regulator installed on the same circuit?
4. For the one ESC that still gets hot even w/o the BEC wired up, is my assumption that that ESC is 'toast' correct?
5. For the other ESCs that got hot with the ESCs connected but now stay cool w/o the BEC connected, are those likely okay?

Thanks in advance for any help!

-Justin