ATX power supply wiring

[BP]

I pulled an 350w ATX power supply from a discarded computer figuring I could
use it as a test bench unit. I've been using a very old 200W unit that has a
simple hard wired off/on switch. I plugged it in and jumped the green wire
on the 20 pin connector to the black ground but the unit did not come on. Do
I have the jumpers right? Or is this a dead unit?
I can hear a high pitched whine when I plug it in. I also recall that some
ATX supplies will not come on unless there is a load. Or is that a load?

 

[Roby]

I pulled an 350w ATX power supply from a discarded computer figuring I
could use it as a test bench unit. I've been using a very old 200W unit
that has a simple hard wired off/on switch. I plugged it in and jumped the
green wire on the 20 pin connector to the black ground but the unit did
not come on. Do I have the jumpers right? Or is this a dead unit?

I have tested several ATX supplies this way. Grounding the green wire
started them without any external load.

I can hear a high pitched whine when I plug it in. I also recall that some
ATX supplies will not come on unless there is a load. Or is that a load?

Maybe some need a load. Try plugging in a spare hard drive before powering
up.