Powering 5v Pro Mini withc 12v psu

So I finally managed to transfer a project from a breadboard to a protoboard and a pro mini. Its only a couple of reed switches and a relay to power a solenoid. I have some 12v power supplies I intended in using with pro minis but I can't seem to make them work. The barrel jack is connected to raw and ground on mini. When I try to power the board with the psu the on light on the mini flashes for a second then it dies down. It works fine with ftdi - usb connection to pc. I tried with 12vdc 1a adapter and a larger 12vdc 6a one.

What is the actual voltage output of the power supplies? I.e measure it with a multimeter. If it is an unregulated supply the voltage will be higher when the load is small

Are you sure you have the barrel jack wired correctly? And did you solder the connections?
With a multimeter, while the PSU is connected and powered, measure the voltage between the Pro Mini “RAW” and “GND” pins, to ensure that you actually have the connections right.

What else is being powered from the 5v regulator?

Could it be that the load is too heavy for the shitty regulator on the pro mini to handle? Most pro mini's use a regulator in SOT-23-5 package, which can't dissipate that much heat, so the current you can pull from it is severely limited.

Alright i think i fried the voltage regulator on 3 of my minis. They are cheap ones from aliexpress. Barrel jack is soldered correctly. Multimetar reads 12.45v on raw and ground but no lights whatsoever. They work fine on ftdi so regulators are dead I guess. What am I doing wrong?

The voltage regulator on the mini is normally something like a mic5205 which can provide 150ma max. It is a linear regulator so the higher the input voltage the more heat it produces. At 12v it could be producing quite a bit and unless it's tab is soldered to a nice large ground plane it will overheat and die.
I would recommend you search for "lm2596 buck" on eBay and get one of those and adjust it to 5v. It will give you far more power to play with if you need it.