I'm trying to set up a new APM2 and have an issue with the input power rail. I suspect I'm doing something wrong.
I'm powering my FC using the power from an ESC's BEC on the output rail. Coming from the BEC I see 5.1 volts. The board seems to power up fine that way. If I don't have a receiver attached to the input rail, with a DMM I measure 4.9 volts across the +/- pins on the input rail. If I attach a receiver that voltage drops to 3.2 volts and isn't enough to power my receiver. If I power the board through the USB port, I see 3.6 volts across the input rails with nothing attached, 0.7 volts after I attach the receiver. The power jumper is on.
I've tried this with 3 different receivers and get the same results. I've checked that I have the +/-/S pins correct about a zillion different times.
I'd really rather not remove the power jumper and have to worry about powering both sides separately.
Has anyone seen this behavior before? I spent a bit of time searching the forum and haven't seen any other postings like this.
Thanks
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