Computer Power Supplies...a question.

[Jim O'Dell]

Will they not power up if not plugged into a motherboard? I built a housing for my cable modem and router with 2 fans in it. I thought I could use a power supply from an old computer to power them, but neither of the ones I have will work that way. I know one of them was powering this computer until I got a bigger unit for it cheap. (free!) So I can only think that it has to be plugged into a computer to power up. One of the 2 I tried has it's own switch that mounted to the front of the computer case. I kept that intact, but still no dice. But it is out of an unknown computer case and may be bad to begin with.
Right now I have my wife's tower top off with my "box of fans" for the modem and router plugged into a spare wire there, but it is an unsightly mess, and when she powers down her computer, the fans go off, and shortly thereafter, the net goes down and I'm done for the night whether I want to be or not. Any ideas on how to make this work? Thanks! Jim.

[Bob Vavricka]

Jim,
They will work without being connected to a motherboard. I used one to make a bench type power supply last year, but I don't remember the particulars. Here is a link to one site I found with a quick google search and you should find a lot more to compare it to.
http://www.wikihow.com/Convert-a-Computer-ATX-Power-Supply-to-a-Lab-Power-Supply
Have fun.
Bob V.

[paul cottingham]

You must make sure the atx power switch lead has a way to be switched. without that, the power supply will not power up.

[Jim O'Dell]

Bob, Thanks! I brought the power supply back to my computer so I could look a the diagram and opened it up. Following the wires, there was no reason the power supply switch (the one with the front case switch) shouldn't power it on. I plugged it in again, and it came on fine. Took it back to LOML's computer, and it still works fine, so mission accomplished! Thanks for the site. Without that, I would have given up for a while.
Paul, I'm sure that is why the newer one didn't power up. Luckily, the older one had it's own switch!
Jim.