New z77 extreme4 won't power up with switch - sort of

[bluthndr]

Just assembled a new build with an extreme4 z77 mobo. Wouldn't power on at first. Checked the psu by jumpering the green and black wires (4th and 5th ones in on the 24 pin connector). PSU checked okay. Forgot the jumper was there and plugged it in with psu off and unplugged. When I power on the psu, case fans come up, I/O panel illuminates, and the power switch then will fire everything up.

Jumper can be removed with system up and running and all remains well. Loaded windows, several restarts went fine. However, when fully shut down, the system will not power up again without jumping the 2 wires long enough to hit the power (on) button.

No codes at all on the debug panel, and the "on (mother)board" power button acts the same way as the button on the case. Once up and running everything works fine, but when shut down fully (not shutdown-restart) it will not power up without the jumper being there - as soon as you press the power button the jumper is no longer needed.

System specs are:
3570k
Corsair H100 cooler
Z77 extreme4 (asrock)
2x4gb corsair vengeance ram
Tx750m Corsair PSU
C70 Corsair case

What am I missing? Help!

 

[markwp]

Sounds to me like you have the on/off switch reversed with the reset switch. Check you switch leads to be sure you have the front panel buttons on the correct headers.

Mark

 

[bluthndr]

I switched the RESET and POWER two pin connectors on the front header panel just to see, and it's the same result.

Just to clarify, from a powered-down state, without the jumper, it is like nothing is even plugged in to the wall. Jumper the green and black wires in the 24-pin just long enough to press the power button, and everything runs fine until powered down completely the next time.

 

[markwp]

Just on a whim, try a cmos reset.

 

[bluthndr]

No joy on the clr CMOS.

So far I have tried:
Clr CMOS
Unplugging and reconnecting all power connections
Moving fan plugs around so that cpufan1 and cpufan2 have both had at various times: The H100 Pump connection, a 4-pin pwm fan, or a 3-pin fan.
Trying it with and without a video card installed.
Moved the power and reset connectors to every reasonably possible positioning on that part of the header panel.

It continues to operate completely normal after it's on, including flawless shut-down restarts during the install process, but requires that I "jump start" the PSU whenever it has been powered off after a "real" shut down.

Does anyone know how the PC/mobo "tells" the PSU to come on? The power button must work as it does have to be depressed once after the PSU is jump started, before the PC will actually power up. For some reason the PSU is not coming to life, but I can't tell if that's because it just won't on it's own, or the mobo is not telling it to. Are there PSU pins or mobo pins at the 24x or 8x connector to diagnose the problem? AsRock's "manual" is pretty weak on that.

 

[markwp]

Do you have a different psu you can try to rule out a psu sensing issue?

 

[bluthndr]

Do you have a different psu you can try to rule out a psu sensing issue?

Swapped out the Corsair TX750M for an old Antec 650 that is too small for the system to run full power, and the Antec powers right on when I hit the button. Looks like the Corsair TX750M PSU is off for repair/replacement, and I will wait for my new one to arrive.

 

[markwp]

Outstanding. Persistence pays off!

Mark

 

[bluthndr]

UPDATE: Just received my replacement TX750M from Corsair new in box - even with shrink wrap. All told, it was probably a 2-3 week turnaround after figuring in my delay in shipping it. On the negative side, who can afford to be without a PSU for 2-3weeks? On the plus side, no hassle from them, and they went above and beyond sending a brand new (complete) PSU with cables, when all I sent them was the core unit by itself with no cables.