Power RPi3 from GPIO pins?

[John Public]

I faulty power source broke down with sparks an all on when connecting it to Rpi3 miniusb connector. The Raspberry looks ok with no visible damage after careful inspection. I connected a good power source but I could not get the RPi3 to boot up: no lights, nothing.
Since it looks ok I suspect the usb has shorted and not working. I'd like to try to power it up from GPIO instead. Are there any caveats to that? I do not want to break the other RPi if a short someshow causes the a short in the working RPi. What about amperage? I have an Orange Pi with a 3A power source and I might piggy-back power from it's GPIO.

[davidcoton]

Depends what broke. PSU fault, or fault on the Pi? Did you try plugging in a live supply? (Bad idea, prone to shorts and disrupted startup.)

Possibly if the PSU produced overvoltage the polyfuse has tripped, it will reset over a period of a day or so.

Powering from the GPIO bypasses all the protection circuits, do it at your own risk. Particularly if your PSUs are flaky (the "official" Raspberry Pi supplies are good).

I do not know how much power an Orange Pi uses, but the recommendation for a Pi3B (allowing for normal peripherals) is 2.5A. So a 3A supply may not power two SBCs reliably, or could be fine.

However, I do not recommend supplying your Raspberry Pi from Orange Pi leftovers. You could cause psychological damage.

[John Public]

After inspection with powerfull magnifiers it appears that a black "thingy" next to where the microusb is connected appears burn out. So I powered it via 5V pin 2 and ground and lo and behold! it works again. I just love these SBCs!

[pws]

Don't forget Mr. Cotton's advise:

"Powering from the GPIO bypasses all the protection circuits, do it at your own risk. "

[davidcoton]

After inspection with powerfull magnifiers it appears that a black "thingy" next to where the microusb is connected appears burn out. So I powered it via 5V pin 2 and ground and lo and behold! it works again. I just love these SBCs!

WHICH black "thingy"? What is the label on the board? Attach a photograph with the part marked if you are not sure.
(Obviously you have a working solution, but idenmtifying the part may help us work out what happened and how to avoid a repeat).