Fatal1ty Z170 Gaming-ITX/ac failed to initialize

marcos wrote: Hi All, Maybe you can help with some advise in regard my problem to find out whether the problem is in the motherboard, PSU or case. I press the case's power on button just for an instant, the system powers on and everything works. Running Passmark tests several times with no problem at all. However, the mobo does not initialize correctly when doing like this: 1.- Turn off the computer. Just a regular Windows shut-down. After shut-down, I do not swith off the PSU power switch. 2.- Press case's power-on button, I keep it pressed, let's say for 1 second. I can not see BIOS screeen (no signal in monitor). I can see case fans working (not at the speed set up in BIOS, but faster), CPU fan stopped!, HDD spins, VGA with power (VGA fans working).  The only way to continue is to switch off the PSU, and keep the system with no power for some seconds. If I wait for some seconds, and then switch on the PSU and press the case's power on button (no matter whether I keep it pressed or I press it for an instant), the system works correctly. If I do not wait those seconds, and I switch on the PSU without waiting, I find the same problem. In this example, I do not need to press case's power on button, the system tries to power on by itself, but find the same problem. My config: - Fatal1ty Z170 Gaming-ITX/ac - Fractal Design Node 304 (FYI, no reset button). - i7 6700K (no overclock yet) - 2x8GB Gskill F4-3000C15-8GVR (no overclock yet) - 960 Pro NVMe SSD. - WD HDD. - Be Quiet Pure Power L8 500w. - MSI geforce 970 gaming - Windows 10 Pro. Many thanks in advance, Marcos

What reason or purpose do you have for pressing and holding down the case power button for one second when the PC is in a shutdown state and the PSU is on? What do you think should happen?

When a PC is on and running and you are in the UEFI/BIOS, if you press and hold the power button down the PC will shut off, and be in the shutdown state.

When a PC is on and running and you have booted into the OS/Windows, if you press and hold down the power button, the PC will also shut off, but it takes longer since the PC has been sent a power off signal and the OS performs a normal or quicker shutdown.

The power button on a PC case is not like a switch used to turn lights on and off.

When it is not being pressed, the PC power button circuit is "open", just like a light switch is when it is in the Off position. There is no connection in the circuit between the mother board and the PC case switch.

When you press the PC case button, the power button circuit is "closed" or completed. That can be considered a short circuit.

Pressing the PC case button for an instant is used as a signal to the PSU and mother board. How the PSU and mother board react to that signal depends upon the situation or state that the PSU and mother board are in when the signal is received.

If the PSU is on but the mother board is in the Off state, that signal will cause the PSU to come out of its standby state, and send power to ALL parts of the board and all the parts connected to the PSU. The signal sent to the PSU is really from the mother board itself, which is reacting to the signal from the PC case power switch.

The momentary pressing of the PC case power button actually has a defined time span, in fractions of a second, of how long the circuit is closed. The mother board "knows" a signal within the time span is a signal from the PC power switch. After that amount of time, the mother board must consider the next signal from the PC power switch to mean to change the PSU to the opposite state that it is currently in. That means if the PSU is fully on and making the PC work, then this signal means shut off the power to the PC and go into the PSU standby mode.

I may not have explained this well enough for you, but the main thing to know is pressing and holding down the PC case power button when the PC is in the shutdown state, and PSU is in the standby state, causes the mother board to receive a turn on signal and then a turn off signal so quickly that the mother board's control of itself and the PSU become confused.

The rules or standards for the signals a mother board receives are broken in this case, and the result is a non-normally working PC. As you know, you must remove power from the PSU (and the mother board too) which allows both to be set to their off state without confusion.

I really do not understand why you think what you are doing should be fine, or that something is wrong. Some PC case switches might be fool proof, and only short themselves for the amount of time to give the board a signal. The switch on your case does not have that feature, so if you hold it down too long at the wrong time, you will get the results you do.

How do you think the switch should work?