RAMPS 1.4 Mega 2560 Keeps Frying!!! (3 replies)

hello everyone,

So for some reason my first ramps board decided to fry, for no reason what so ever. So i ordered a replacement Arduino and ramps board, once wired correctly i powered it on and the LCD didn't turn on, then after about 5 seconds, i was greeted with MAGIC SMOKE from the mega, it looks like the voltage regulator on the mega had fried as it had a burn mark. So after much door kicking i ordered another mega, but after connecting THAT FRIED again! After reconnecting my door to its hinges i then, looked into why it was frying for the next 3 hours, and found nothing that could help, So i came to the conclusion that my ramps board was defective, so ordered a whole brand new kit. But, surprise surprise, this FRIED ASWELL!!! Please, what is happening here!

All the connections are correct and are not shorting out
I have soldered D1 onto the board correctly
Bed resistance is correct
Stepper drivers are in correct
my ATX psu is outputting about 12.2V, which should be fine

I have tried removing D1 so that the Mega is powered via a USB connection, but again i get no LEDs no nothing.... However when disconnected from the ramps board the mega powers up fine...

So here i cam with 3 fried megas, and 3 currently useless ramps boards, please what do i do...