Smoked T3.6, which part(s) most likely damaged?

[Fyod]

Excited to get some stuff working, I forgot to cut the 5V trace with an external supply on VIN.
I don't want to throw the board out and I'm fine with soldering small parts, but I'm unsure what let the smoke out.
Iirc, I think I saw smoke near the processor (between the CPU and SD slot), I think there's and Vreg there.
I now have 0.2V on the 3.3V line when plugged into USB and the fuse gets very hot in a couple seconds.
Is there any hope?

Cheers!

 

[PaulStoffregen]

Is there any hope?

Might be some small hope. Sounds like something is shorting out the 3.3V power. If that's the main K66 chip or the KL02 bootloader chip, then the board is ruined. But if there's some other path all the current is taking, through something else, if you can fix or remove whatever that "something else" happens to be, maybe you'll get back to 3.3V power and the board working. Maybe...

If other stuff is still connected, start by disconnecting everything from the Teensy. Then look around the board carefully with a magnifier and bright light, looking for anything out of place that might be shorting the 3.3V power.

But if it is ultimately either of the 2 chips, there's really no realistic way to replace those.

 

[Fyod]

Wow. Thanks, Paul. I had already had all extras removed so I pulled out the magnifier and there was a minuscule splinter of solder/wire along a capacitor.
Seems to be working great now. Sometimes all it takes is an old toothbrush.