Question about RAMPS 1.4 boards

Hello all,

please forgive if this has been asked, I searched and couldn't find anything similar to the issue I am having.
I started my quest to creating a DIY CNC machine. I went with the project Root 2 CNC multitool router 3D printed parts by sailorpete Root 2 CNC

I have the Arduino Mega and RAMPS 1.4 board with a 12V PSU.
So far I have blown two RAMPS boards out instantly upon turning on the PSU.

I have thoroughly checked my PSU and...

Question about RAMPS 1.4 boards