GA-Z77X-UD5H Delay Responding to Power On Button

[sc489]

My PC is powered fully off in Windows and turned off at the mains switch. To start the PC, I turn on the mains power (the PSU switch is already on) and then press the ON button on the PC front panel.

The PC won't respond to the front panel Power On button until 10sec after turning on the XFX 850W PSU.

I changed the CMOS battery since it was only 2.7V, cleared the CMOS and loaded the BIOS defaults. However, I still have the same start up delay. I noted the following behavior of the power button / light on the edge of the motherboard (next to the alphanumeric display).

1. Power on PSU at main switch after PC has been fully off for over an hour.
2. Motherboard light stays off for 5.5 secs then flashes for 0.5 sec, turns off, flashes again at 8 secs for 0.5 sec then stays on at 10 secs.
3. The PC will only start using the front panel power button when the light on the motherboard is fully on i.e. 10 secs after switching on the PSU.
4. PC then boots to Windows 8 OK and shows A0 on the motherboard display.

Please advise:

1. What does the flashing motherboard light on power on mean?
2. Is the 10 second delay before the motherboard responds to the front panel power switch normal or do I have a problem with the motherboard or PSU?

[dmdilks]

Have you tried another PSU to seen if it is the PSU.

[sc489]

I've now disconnected the main motherboard cable and found it takes 5 secs for the +5V standby voltage to appear after the PSU is switched on. The voltage is stable at 5.14V once established. I suspect the PSU may be faulty since it should output the +5V standby sooner than 5 secs.

How long should it take generally for the PSU to establish the +5V Standby output?

[dmdilks]

I could see it do it when you turn the switch off but not on. When you turn on the PSU it should come on not wait. On all boards the lights will stay on after you turn the switch off for about 5 sec. Even if you pull the plug out it will still take time for the lights to go out.