Originally Posted by tc3wins
what type of standoffs are you using for the board?
Funny thing you should mention standoffs. Quick story here:
I received my QuaRino board a couple of weeks ago and it went out on me withing the first few minutes of use. I worked with Colin on the issue and ended up sending the board back to him. He found a blown diode, replaced it, tested it, and sent it back to me. I just got the board today, mounted it, connected only the Signal line from the ESCs to the motor pins, and powered the board via a BEC connection to the Rx. When I attached my flight battery...nothing. The board didn't lite up, neither did my Rx. I removed the power lead from the Rx to the board, connected the flight battery again and the Rx lite up. Reattached everything, powered up, nothing again. I pulled the board off the standoffs, attached the battery, viola, the board lite up. I did a little more investigation and found a test point very close to the rearmost mount hole. The standoffs I'm using...ALUMINUM! Apparently the standoff was shorting the ground plane of the board and whatever the test point connects to.
To fix, I grabbed some old servo vibration isolators, cut off part of the end piece, installed the rubber isolator between the board and the aluminum standoff. When I attached the flight battery...everything lite up fine and I was able to get some trim and control adjustments in with no problems. Well...almost. I think the same diode blew again as the board won't power up with a Rx battery attached to the motor pins. Colin had sent me some spares, just in case, and it looks like I'll need to use one. That's not a biggy unless you power the board from the motor pins...which I'm not.
So...moral of the story, use either plastic or rubber standoffs OR install some sort of insulator between the board and the standoffs if using metal standoffs.
FWIW (everyone)...have you read how the board reacts to Rx failures? If the board is powered via the motor pins OR the Vin pin and you lose the Rx the board will continue to fly the quad...uncommanded. That could be a safety issue...a flyaway quad. If you power the board via the Rx pins and lose the Rx the quad will quit and drop like a rock. I'd hate see see a crash, but that's a lot safer than a flyaway quad IMHO.