Nano acting differently when powered via VIN

I have a clone Nano (with the 5v regulator from a genuine nano) which I am trying to power from a 19v supply with a 12v regulator to VIN. My problems is are:

When powered via usb alone, the SPI screen works perfectly and voltage reading from the analog pins are accurate
However, when I plug the 19v supply in (whether usb is connected or disconnected), the screen just stays white and voltage readings only read 0.00v!

I believe my genuine nano had the same issue before it broke

The 12v regulator is a reliable output and the onboard 5v reg should be better than the AMS1117 I replaced.

Any clues?

There are two common pinouts for 3pin regulators. Did the replacement regulator pinout match the original regulator that was on the board?

Now that is a good question.. I was not aware that there was a possibility of having different pinouts.

The genuine regulator is marked as an ST Electronics LD50 F703, however I cannot find the datasheet for this so i cannot confirm! All i can find are similar ST regulators marked LD1117.

The clones original regulator is marked AMS1117 5.0 S1718E

The datasheets of the AMS1117 and the LD1117 show an identical pinout. I will swap the regulators back and report back

UPDATE: After swapping, it mysteriously works now? I dont understand why because when i changed them i checked pinout with the multimeter... it is the same. You could tell that the sketch was running by looking at the LED but it seemed to be just SPI that was broken. Both regulators were outputting a solid 5v but the genuine one is known to be more reliable under 12v input. So backwards..