You can buy replacement parts, pretty much anywhere! I use classifieds here, and also craigslist, eBay, Amazon, local hobby, ect! I price shop a lot, as I'm always tearing stuff apart! Lol, I love it, plus you'll learn a lot more about your craft, by doodling around with it!
There are only a few MAIN components!
1) your MAIN BOARD, this is the LARGE flat board under the lid of your bird ( the NAZA-m unit ) sits a top of it.
2) RECEIVER BOARD , sits just under main board ( right side, if front facing away from you )
3) ESC's ( electronic speed controls )
There are ( 4 ) all the same! If craft is older they are version 2.0, if craft is newer they are v2.1. The 2.1 say it on the white label on esc. Make sure they stay the same, or you'll have a very WIERD startup! Happened to me! Lol Muhaha ha ha!
Then the MOTORS, but as long as you put a bit of oil on the bearings or replace them, motors should be fine!
So
I'm not sure what you toasted? Could be only a esc, or could be a lot of stuff?
First does it come on at all?
If so what is it doing exactly?
Do you get the red-yellow-green gimmick with the doodle-doodle -doo-beep-beep-beep-beep?
What are each arm doing light wise?
If it starts up with turning on battery, I'd first hook to PC do a advanced IMU calibration, then a fresh compass calibration, after that try to engage motors, make note of which work and which do not, I'd start with the esc on motors that don't start, or act erratic! Your receiver board is fine if remote still make contact to craft like doing the CSC, to start motors!
Worst case new main board, and 4 esc's best case a bad esc or 2?
You'll have to check it out.
Do you have a volt meter?
You can also check voltages at solder points ( take note the clear coat the joints ) so you'll have to scratch it a bit to get connection. You should have 11.1v at main board and 5.v at esc's if not main board may be bad?
But that is how I do it!
When you do repair follow these guidelines!
1) hook Tx to RC ASSISTANT, do FULL calibration, both sticks, toggles, dial wheel ( if avail )
2) hook bird to PC ASSISTANT, do full calibration on Tx again here ( RC assistant calibrates sticks, toggles, dial wheel to Tx, PC assistant calibrates Tx to bird )
3) do ADVANCED IMU calibration ( bird STABLE, LEVEL ALL DIRECTIONS )
4) take outside, do fresh COMPASS CALIBRATION!
If all goes well ( I know it will ) you should have a shinny, stable, beautiful new bird!
I'd be glad to help if you need guidance! I have never found a schematic, I take lots of pictures, and look back as reference!
Lastly
Motors are all the same ( only different bell ) cw or ccw motor base are all the same only tops different
And wired different
Esc's all the same only wired different!
Hope this helps!
J Dot