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blueonblack
03-29-2008, 05:05 AM
I am having some trouble hooking up both power supplies in my new build and hoping someone with more experience could shed some light on my problem.

I did some testing with jumper wires and the main ATX cables before taking the PSU's apart and, as expected, when the first PS (I'll call it the primary) was powered on, jumping a wire from the PS ON pin on the primary PS to the PS ON pin on the secondary PS turned them both on. Easy.

I took them apart and ran a permanent jumper from the PS ON wire on the secondary to the PS ON wire on the primary. I hooked up the jumper on the ATX cable to short PS ON to ground. Both PSU's came on.

Then I moved them. One shut down. I unhooked the jumper and the secondary came on by itself, like it was finding ground somewhere for the PS ON circuit. I took them apart and checked my insulation, all is well.

The strangest thing happened. When the secondary came on by itself, I could move the two PSU's around a little and it would shut off. I shut them both off and back on and nothing happened (no jumper). About twenty seconds later, without touching anything at all, the secondary came on by itself again (again with no jumper to short PS ON to ground).

I tried putting the jumper wire inside a shielded cable, thinking I was picking up EM interference from a coil or something, no help. Sometimes (and only sometimes, mind you), I can remove the ATX cables and touch the jumper wire on the secondary to the jumper wire on the primary and the secondary comes on. But the primary isn't, so that circuit obviously isn't grounded.

I am about to go out of my mind here. This seemed like (and still seems like it SHOULD BE) such a simple operation, but I am not having any luck at all, does anyone out there have any ideas on this problem? Any input would be greatly appreciated thanks!!!

John5247
03-29-2008, 06:37 PM
Do you have any loads on these supplies. Green to ground is a momentary contact, but "power good" and "no load protection circuits" are continuous. The supplies may be firing up, then, finding no load, shutting down again. PSU's have lots of differnet protection circuits and even the same make and model will react differently due to componenet tolerences.
Get a couple of 20 watt 12 volt dichroic lamps and wedge them accross a pair of yellow and blacks on a HDD Molex.
much cheer
John

blueonblack
04-04-2008, 12:48 AM
Thanks for the help, guys, I got it figured out. Wooooo hooooo! :glasses: