power supplies blowing up

[ak5fxke9]

Hi. I have multiple computers that have worked for many years in a university lab. Now they have been taken out, and were used to set up a test network. When they are plugged in, though, they blow up. Once power is connected to the power supply, a big electrical zap occurs and they emit smoke. This has happened to four of these computers, some connected to a ups and others on different wall outlets and surge protectors. The kicker is that some of these same computers work fine in the same outlets. This has never happened to these computers before. They won't work after they've been zapped. Any clues? Thanks.

ak5fxke9

 

[neox1]

If you have any other computers that have the same power supply try connecting it to the bad computer to see if it is the computer or the power supply that is faulty.

Neox1

 

[circut16]

check the switch on the back of the power supply, make sure it is set to 115 instead of 230

 

[ak5fxke9]

Thanks guys. The power supplies are all set at 115, and the voltage from the wall is correct too. It is the power supplies, since other ones work to power on the blown computers. It is just weird that four of them blew up while others are working fine on the same electrical circuit.

ak5fxke9

 

[MplsBob]

I am not a network guru.

Having said that, I sure would want to check out that network wiring. Is there some sort of wiring error where you have a signal line connected to ground? It might be a miswired connector or a short within a connector? It might even be that something has mashed down on a wire and shorted two lines together.

Just a thought.

 

[RossGr]

Connecting a PS set to 230V to 115V lines will not damage the PS. The other way will at the very least blow a fuse, no fuse? ... no PS.

 

[Mikendi]

It's been my experience that power supplies to do travel well after being burned in. I liken it to a light bulb who's element gets fragile after months of use. It could work for a long time, but take it out and jar it and poof* - Maybe I'm loony, but I've had used PSU's go pft after being shipped, or otherwise relocated.

 

[ak5fxke9]

Thanks everyone. From what I can see, it probably is just a big coincidence that four of them blew up. We took all of them apart and then relocated them, and they were old anyway.

 

[DARRIN]

Just a thought. I have seen where you could measure between hot and neutral and it would read 115volts but the hot was actually 130volts and the neutral had 15volts on it thus a difference of 115volts. Some stuff does not like this.