Just assembling a new build this afternoon. First time I've tried water cooling (just an AIO, the H115i). Felt like I'd connected everything up properly, and turned the power on for the first time. Okay, some LEDs are on, the pump/cooling unit is lighting up properly, and...WHAT ON EARTH? Black smoke was coming from the USB-to-mini-USB cable connecting the motherboard to the pump. I killed the power as quickly as possible and the wisps of smoke thankfully stopped, but...that cable was VERY hot, and I could see some of the plastic had melted from the black wire in particular (see photo 1).
I've built several PCs before but have never seen anything like this, and I don't even have a first instinct for what the culprit might be. Cable? Motherboard? I was assuming I could use either one of the board's USB headers quite happily (see photo 2 for where I was connecting it).
