🚀 go-pugleaf

Pennywise@DerryMaine.Gov wrote:
>  Al <bigal.nz@gmail.com> wrote:
> 
>> Hi Guys,
>>
>> I have got a mobo here that is dead. I have done all the usual stuff
>> like trying new PSU, bench testing etc. Its dead - as in no fans, no
>> nothing when you hit PWR button - PSU doesnt even come on.
>>
>> I connected the ATX molex from the PSU and shorted Green (PWR ON) with
>> GND on the molex and the PC came on. All seemed fine.
>>
>> I think there is a IC on the motherboard between the PWR BTN headers
>>from the power on switch and the ATX header on the mobo that tells PSU
>> to start up.
> 
> Or the power supply,
> http://www.pcguide.com/ref/power/sup/funcPowerGood-c.html
> 
> Monitor the Gray wire (+5V & +3.3V is ok).
> 
> -Also-
> 
> You short purple (not Green, Green is the wrong wire).
> 

You can get official wire colors, from the Intel specifications
stored on the formfactors.org site.

http://web.archive.org/web/20030424061333/http://www.formfactors.org/developer/specs/atx/ATX_ATX12V_PS_1_1.pdf (page 27)

http://www.formfactors.org/developer/specs/atx/ATX12V_1_3dg.pdf  (page 30)

http://www.formfactors.org/developer/specs/ATX12V_PSDG_2_2_public_br2.pdf  (page 37)

PS_ON#, the signal you ground to start an ATX power supply, is green.

The purple colored wire is listed as "+5VSB" and you don't want to
short that. It is a power output, not a control signal.

*******

To drive PS_ON#, doesn't take a massive driver. The specs above, list
a sinking current requirement of 1.6ma. In cases where there is a
problem, it could be causes by the power supply being out of
spec on that parameter. On the reference motherboard schematics
I have here, some of the driving solutions could handle
a lot more current than that, so whoever the designer was, they
didn't take chances.

    Paul