New ATX Power Supply won't power up 2

[exnext]

I'm trying to rebuild an old PC. I purchased a Micronics M6PI mother board and a new case with an ATX 400 Watt power supply (has an on/off switch on the power supply). My problem is I have no power, no fans, no leds, nothing to indicate there is power to the mother board. I don't have anything connected to the mother board other than the power supply connector. The mother board is not shorted out against the case.
I've read through a few pages of power supply problems in Tek Tips. A few refer to an ATX-sw that needs to be shorted out located at the front of the board with the Hard disk LED, Turbo LED, reset, etc..pins. I have tried shorting out the Reset pin and the KeyLock/Power LED pins, any and all pins but I can't get the power supply to turn on. I don't think it's the power supply because I have another one that is new (without an on/off switch)and it acts the same.
I have metered out the power cord (120v AC) and the 20 pin main power connector (I have 5v DC on pins 9 and 14). I figured the power supply needed a load to have power to the rest of the pins. So I connected power to the hard drive and one fan with no results.
Any ideas what I might be overlooking?
thanks very much

 

[gargouille]

Double check the leads from the case to the motherboard.
Reversing them 180 degrees may make a difference...did you get a manual with the motherboard?

 

[ski]

Make sure the power supply's on-off switch is turned on(Been there, done that).

Make sure the power supply's voltage selector switch is set to the correct AC input voltage(115V or 230V).

Connect the PS o a wall outlet with nothing else connected, and jumper the pin with the green wire to a pin with a black wire. If the fan does not run, then check the wall outlet for proper voltage. If the outlet voltage is ok, then the PS is bad.
If the PS fan runs in the above, then check the yellow wire and a black wire for +12V, a red and black wire for +5.0V, and an orange and black wire for 3.3V. If you do not get these readings, then the PS is bad.
If the above tests ok, then make sure the power supply's connector to the MB is securely seated. Sometimes it needs a healthy push to seat all the way.
Did you jumper the MB's 'Pow-On', 'Power On' or similar terminal?

If the above do not get things running, then the MB is probably toast.

 

[paparazi]

Two things!
CMOS Clear jumper in RUN position.
And as you know, you do need to have something drawing current from the PSU for it to work, CPU fan might not be enough. Martin Please let members know if there advice has helped any.

 

[exnext]

Thanks for your responses.
I jumped out the green and black pins on the main connector. The hard drive spun and the fan came on. I had all the other voltages ski mentioned so it looks like the power supply is good. But, once I plugged the main connector into the mother board I got nothing. Assuming the mother board was bad I left the power on and unplugged the main connector, figuring I couldn't fry it twice. While I was pulling it out, the led on the mother board came on along with the fans and hard drive. Looks like a bad connection. If I push it all the way down I get nothing. If it is 1/2 way seated I get power. I'll look at the connector and see if I can repair it.
Now I'm back to where I was 6 monthes ago. I have a good power supply, presumably a good mother board and no video.
But, I'm going to post that in a new request.
thanks for your help

 

[Stealer]

Had the exact thing happen to me on a E-Machine I was working on a few months ago. No power until I pulled the power connector half way out of the main board. Ending up replacing the power supply.


Stealer

 

[mainegeek]

There might be an extra "stand Off" under the board
in the area of the power connector. It might be worth it to check and see. It might not have been a problem in the bigging but over time boards do begin to sag.