A while ago I fashioned a lazy-man's bench power supply out of an old computer power supply. I simply lopped off the ATX main and grounded PS_ON with one of the 7 grounds (I don't remember why I just didn't take a couple of male pins and fashion a pluggable wire).

Over time, I'd make a mistake and short it out and to get it to power on again I would have to ground PS_ON to a different ground. I don't know a ton about the internal workings on a switch-mode PSU but my thinking is that each ground has a thermal fuse, so when it goes the ground is no longer connected. Is my thinking correct or wrong? Thanks!

 

PSU has a Fuse,PTC Thermistor and a Resistor for protection.The only reason GND isn't working anymore is if you burned the trace/wire.

 

AH, thank you!

 

Take a multimeter if you have and do a continuity test.

 

I has this same issue yesterday on my Dell PSU (April 2004 mfg), accidentally shorted out my +12V and GND and the PSU shutdown immediately. Tried disconnecting from mains and reconnecting but it didn't work. So, tried disconnecting the PWR_ON(green ) and gnd and reconnected it and the PSU turned back ON. I actually just twisted the two wires since I was testing how the supply was handling different loads.

 

interesting. I'll have to give something like that a go. Thank you both steve and rialynn.