Satnogs Controller Board / Circuit / Power question

First off, I'm just getting started into electronics, so i'm very green!

I'm building a satnogs satellite tracker (controller board PCB, Schematics Here -

I ordered the blank PCB's and soldered all the components to it and checked for shorts, etc.

When I power it up, it burns up the arduino pro mini 5v I had. Think it may be pulling too much power and frying the on board voltage regulator on the pro mini. I know it's only capable of 150ma regulated 5v.

My question is, I'm coming into VIN via 24v and the satnogs controller is stepping that down to 12V using it's onboard power circuit. On this satnogs board design, the arduino pro mini takes the 12v in via the raw pin, and steps it down further for 5v to it and the rest of the components to use.

As a testing step, can I remove the raw pin from the circuit and instead inject 5v directly from a buck converter I have just to verify that it is indeed drawing too much power?

As far as wiring the buck converter, do I connect both grounds on the buck converter to the same spot on the controller board? Then the input side to the 12v of the satnogs controller board, and output to the 5v side on the satnogs controller board?

Do I need to worry about ground loops, or any other crazy things that might burn this up?

What all is connected to the Mini’s 5V and output pins? Can you post a wiring diagram?