I hold the on button down on the fully charged battery in the solo. The leds on the battery come on from the center towards the outers, then turn off then come back on from left to right (showing charge level I think).
I then notice that propeller 4 moved slightly and then the battery goes dark.
I'm guessing that's something to do with some internal check or something?
I have nothing to go on and tech support hasn't answered a question I had last week so I figured I'd start here this time.
I'm not a solo expert by a long shot but I did some crash testing with one and found that after the motor was partially stalled when it got stuck in some weeds, one of the motor pods (aka ESCs + LEDs) was damaged and from then on it would power down shortly after powering on. I discovered which motor pod was to blame by removing the LED case, unscrewing the 4 screws below, and removing the pod. I did this for all motors and then it powered on ok, I then added them back one by one until it stopped working again so I knew that was the problem motor. The only solution was to get another motor from 3DR.
I read in the manual that you hold the Solo battery power button for 'less' than 1 second, that's what I do - let go as soon as I see the LED's light up. I'll try holding longer, maybe that causes it to shut down.
Motors don't have a lot to go wrong but I agree, it is likely a motor. Broken solder joints are often the issue for motors. Give all the motor wires a tug, or test the motors individually. Don't through out motors unless you must, but spares are always handy.
Looks like a motor. I took off #4 and Solo powers fine. Nothing looks wrong with it.
Haven't heard back from Solo since posting this. Guess I'll try to call tomorrow.
Again I don't own a SOLO just 3DR FC (Flight Controller) stuff but you could try recalibrating the ESCs. As I don't own a SOLO, you would need to look that up. For APM and PixHawk its just powering up with the throttle full, powering down, then up again then move the throttle to zero. The ESCs make at few noises at each step. It shouldn't effect the FC or the OBC.