That takes me back...
I had an old fan plugged into molex in my old pc, when I decided it needed some lights. So I took apart an old tec project, and wired the pcb into the molex plug (it was only providing it a couple too many volts.
Well it all worked, minus 4 or so of the LED's, so I thought that I would get a bit of solder, and make it skip over the bits of the PCB which were meant to control the flashing of the LED's. . All went to plan, and all the LED's went on, untill I moved the stick of solder, and shorted the molex connector , shorting the whole PSU. *I will note here that the PSU was a freebee, from a company I have never heard of *. Pop and off it went.
A bit later (after removing the PCB) I tried it again, it worked, so I covered the wires with a bit of tape, and the system now runs in my bothers room