PSU failure and flashing green light? Find a hair dryer
So how’s this for a nightmare situation: you turned the power to your server off last night, to allow some electrical work to be done. Next morning, you turn the server back on and… nothing happens: nothing lights up, none of the fans are turning, everything seems dead – except for a solitary green light flashing away next to the power inlet. Pull the power plug out and the light stops flashing: plug it back in and the light’s flashing again, but the machine still won’t turn on.
Yes, everything important is backed up (or at least I think it is), but what do I restore it to? Thankfully my desktop PC still connects to the Internet, so in desperation we do a Google search on ‘psu failure flashing green light’. The result: a whole bunch of references to hair dryers, which all sound totally crazy, but what the heck, I’ve got nothing else to try. Unsurprisingly, no-one in the office has a hair dryer to hand, so it’s a quick trip home to borrow one. But what’s totally amazing is that it actually works!
What you do is take the side panels off the server box and then plug it into the mains, so the green light is flashing. Then play the hot air from the hair dryer around the light and around the power supply area with the object of generally raising the temperature of the metal. It takes some time for the heat to permeate into the internal electronics, but just as I’m thinking WHAT AM I DOING THIS IS CRAZY, the green light stops flashing. I press the power switch and the server boots up as if nothing’s happened. And it’s still running now, 12 hours later.
It’s all to do with the fact that the server hadn’t been switched off for such a long time for years, and the temperature within the power supply had dropped causing metal components to shrink, and brittle solder joints to crack. Heating it up caused the metal to expand and the solder to soften, restoring a broken connection somewhere. It’s only a temporary solution but it gives me time to get a new server, or think about moving it all out into ‘the cloud’.
So if you find yourself in a similar situation, go find a hair dryer before you do anything more drastic.