I needed to test the Nixie Tube Power supply, but I didn't have any 12V wall plugs, so it was the perfect excuse to finally finish my ATX benchtop power supply so that my little desk top circuit lab could have a decently regulated 3.3V, 5V, and 12V source (not to mention Ground and a bonus -12V). I followed a tutorial from this great video (I am not affiliated with them at all, it's just an easy to follow guide), where he does a very thorough walkthrough on creating a nice bench top power supply out of an old ATX power supply. I used a red LED on mine to show that it had AC power connected, and a green LED to show that it was switched on and delivering power to the screw terminal. I accidentally shorted out the first power supply that I attempted to do this to, because I forgot to connect the ground from the AC adapter back to the ground on the bottom of the power supply and I moved the top shell into contact with one of the heatsinks inside, shorting out the power supply and welding the top of the case to the heat sink. It wasn't worth saving so I trashed it and used a second old power supply I had laying around.