Early production DEVO 6 has a battery drain issue. Even with the transmitter turned off, batter would drain in about 1-2 weeks if is not plugged into the charger. I measured a drain of 3.5 mah with the radio off. Others measured 4 mah. That parasitic drain is considered quite high, and over time will deplete the battery. bytemuncher on rcgroup.com asked Walkera about a fix, and they sent him a diagram. Unfortunately, the diagram was not too clear.
I read the diagram and interpereted it as best as possible, and studied the circuit to see if it makes sense. The result was the fix worked. Here is the step by step direction.
Take out all 4 rubber grip pads. They are held in by nubs. Pull starting at the location with the notch. Pull one at a time close to the nubs so they don't break off.
5 torx screws hold the back cover on. I used a 2mm hex key to loosen the torx screws. Worked good, but be careful not to strip them.
Here is the root of the issue. Current is draining thru the voltage regulator. The voltage regulator is not used for normal operation. Is only used for controlling the voltage when charging the radio. Unfortunately, when the radio is off, and is not charging, current go reverse thru the regulator,and drain the battery. This picture came from Wakera, and the red letters was direction for the fix. It was not too clear for me.
Here is my interpertation of the fix, hopefully in easier to understand verbage.
Here is the final fix. This area is located on the left side of the transmitter once the back cover is off.
Use x-acto to cut the copper trace. Use volt meter to make sure connection is seavered, or cut several more times to make sure. Solder the jumper next to the chip.
Walkera said to use 1N5819 diode. That is the diode that is already on the board, so no need to buy another one. I used desodering braid with liquid flux to suck the solder out of the diode. Then it just popped off. Be sure to use flux with the braid so solder is wicked quickly into the braid.