PC Power Supply - Turning On ?

[Oldskool]

I'm going to use a second dedicated PC power supply for my cab's bell and whistles, but it just dawned on me.....

Without the PC's start button, how do you get the power supply to turn on?

Do I bridge a couple of the wires that would go to the mobo?

[Sephroth57]

yeah theres 2 wires you bridge from the mobo pins.... ive seen a link to a diagram on the boards before. just not sure where. someone will probably post it for you

[civic83]

Assuming your using an ATX power supply, all you have to do is bridge pin 14 to any of the grounds (pin 14 is usually a GREEN wire, but check wiht your manufacturer), conviniently there is a ground at pins 13, 15, 16, and 17.  I just cut the wires from pin 14 and 13 and soldered a spst switch between them so i can just flick it on to power it up, also, you can run a led form one of the 5v lines to a ground if you wish to have a "power on" indicator for the second power supply, sometimes helpful in troubleshooting.

http://www.gideontech.com/guides/psu_powerup/
this link has more info

hope this helps

[papaschtroumpf]

permanently shorting the green wire to ground would cause the power supply to be on all the time. If that's the desired result then you're fine. Otherwise you would probably need to tie the green wires between the two power supplies and tie two of the black wires together, this way when the mobo shorts the green wire from its power supply to ground, it will do it for the other power supply too.

[Oldskool]

Thanks for the replies guys.....

I've just dug (the power supply) out of the basement, and the colours / connectors don't sync with what I've read so far in this thread.

Perhaps it's a AT supply.

The connectors are labelled P1 and P2, and the wires consist of 4 blacks, 4 reds, 1 yellow, 1 orange, and 1 white.  

Any help there? T.I.A.

[papaschtroumpf]

if the part that connect to the mobo is in 2 pieces of a single row of pins, it's AT
if it's one single connector with 2 rows of pins, it's ATX
(see pictures on sites referenced above)

The colors on older ATX supplies are not always right, you can always go by pin number instead (on one of my supplies the green wire is purple instead)

[Chris]

Sounds like an AT supply, so it should have a separate switch.  You can probably replace that switch with a relay and connect the relay to a power connector on the PC power supply to get it to fire up automatically...

--Chris

[fredster]

My pc has a bios setting on power interuption.  I set it to to power up by itself.  So when I plug it or power it up with the power strip, it comes on automatically.

[Oldskool]

if the part that connect to the mobo is in 2 pieces of a single row of pins, it's AT

Then it's definately AT.

Sounds like an AT supply, so it should have a separate switch

I can't look at it right now (I'm at work) but I'm pretty darn sure that it doesn't have a separate switch on the body of the power supply.

[Chris]

Sounds like an AT supply, so it should have a separate switch

I can't look at it right now (I'm at work) but I'm pretty darn sure that it doesn't have a separate switch on the body of the power supply.

It won't be on the body unless its a really old IBM supply... it'll be a set of leads (3 or 4, I think) ending in insulated quick disconnects that are meant to connect to a switch on the case.

--Chris