I am quite new to arduino, so I wouldn't be suprised if this is caused by a mistake I made.
I very recently recieved my first Pro Mini's (a 5v and a 3.3v pair). After soldering on the provided headers, I wasnt sure which was which (perhaps I missed a label or some sort of mark?). So to figure that out, I tried to power one up through its Raw pin, and measure the voltage on the Vcc pin.
I connected it to my power supply, set it to 9v and enabled the output. The green LED lit up as expected, but I also noticed a red LED flashing as well (at pin 10). I thought nothing of it, and went on to measure the voltahe, but as soon as a probe touched the GND pin, both LEDs went out. Not even pressing the Reset button helped. Needless to say, I did not try this on the other one.
I read a few posts about the flashing red LED, but noone had their Pro Mini die on them.
Can someone tell me what I did wrong? Or was it a faulty unit? Any help would be much apprechiated. Thanks in advance.