Asrock Z170 EXTREME4 Strange behaviour

[krsta]

Got the motherboard free of charge because it was not powering on.

8 pin CPU power connector is not shorted, and all pins are acounted and ok.
So i put the Pentium G4400 inside presed the MBO power button and still nothing.

5VSB is present and 3.3V also.

Now the strange part.

If i press and hold power button for few seconds nothing happens but if i press it again (1 short press) after the long press the mbo starts and i see the 19 debug code on display.

I then power it off (long press).

After this procedure the motherboard starts and boots to windows, works normally.

When i shutdown, the cpu fan stays on indefinitely.

The comp will turn on normally untill i disconnect it from outlett and leave the capacitors to discharge. Then the whole procedure needs to be done again.

No bulged capacitors or leakage noticed.


Any ideas?

[captainKKK]

Re: Asrock Z170 EXTREME4 Strange behaviour

FORCE a reflash of the BIOS and clear the NVRAM

[krsta]

Re: Asrock Z170 EXTREME4 Strange behaviour

FORCE a reflash of the BIOS and clear the NVRAM

Flashed both bios chips with latest 7.50 bios version -> same symptoms.

Then flashed the same version of Intel ME FW (11.8.50.3425) -> same thing.

I noticed when installing drivers that LAN card cant be installed and it has
"Error while starting" so i disabled it in bios, and now everything WORKS(except LAN card).

No more 19 error on debug display,
no more fan spinning when MB is off,
i noticed that when MB hanged with 19 error main bios led was lighted properly, and secondary was dimming.

Am gona take a look on lan circuit.