Solved W-7 will not shut down

[idahjo]

That is now two of us anyway

Some of the suggestions elude to the 'green wire' as being the sole connection to the MOBO. If so, it has to be a control circuit allowing the MOBO to turn the PSU off and on. Got to thinking and just unplugged the 24 pin main power plug from the MOBO and the PSU still runs until it is unplugged again. To me, that would suggest the MOBO may have dodged the bullet and the PSU took it in the shorts (no pun intended) :sarc:

If the PSU output voltages are present then the control circuit from the MOBO is being negated by some sort of stuck/fried relay system within the PSU. IS that possible? If so, is the MOBO not booting because it is required for the PSU to recycle as the first step of the booting process?

Realize this is getting a little technical and probably something most do not know, but I do not want to tear down another computer to substitute a 'good' PSU so will have to buy one if what I am thinking is a possibility.

Thanks a million for any and all suggestions

I agree, sounds like a bad power supply.

Inasmuch as the 24pin main power plug has the 'single green wire' in it I would think it almost has to be the PSU. Wish I knew when/how the MOBO sent the signal thru that wire to turn the PSU on

 

[Ranger4]

As far as I know the PSU has nothing to do with shutting down a PC. This operation is controlled by the MB.

 

[Holmes177]

As far as I know the PSU has nothing to do with shutting down a PC. This operation is controlled by the MB.

True, the MB controls the power supply, but if the 24 pin connector is disconnected from the MB, and the power supply fan(s) continue to run, then that is an issue with the power supply.

 

[idahjo]

Here is the technical answer I was looking for

Hope I am not breaking the rules by posting it Isolating ATX SMPS Supply and power related faults - PC Hardware Troubleshooting

 

[idahjo]

Purple wire tells the tale

My STANDBY (Purple #9 in the MOBO main power plug) is 1.74v "Should be 5v +/- 5%- If the standby voltage is not in spec or the led(s) are not lit, your PSU may be bad or the mobo may have a short.

Conclusion: Believe the PSU switching relay is shorted, and the MOBO ON SIGNAL (Green #14 in the MOBO power plug) is latched at 4.75v. Both are probably 'fried'.