Yes dc42 it worked fine with just the USB, both USB and 12v, and 12v only.
It's strange. I swapped a mega from another project I have and all is good !!!
So it was the mega. It worked out good because the burnt up mega works fine connected to USB only and that's how I'm using it in the other project.
Now I have end stops with only 3 wires (I soldered the 2 gnds together at the sw and clipped the other gnd wire). So late one night I don't make the same mistake.
Thanks to everyone.
It's strange. I swapped a mega from another project I have and all is good !!!
So it was the mega. It worked out good because the burnt up mega works fine connected to USB only and that's how I'm using it in the other project.
Now I have end stops with only 3 wires (I soldered the 2 gnds together at the sw and clipped the other gnd wire). So late one night I don't make the same mistake.
Thanks to everyone.