ASRock Z77 Extreme 6 not powering up

[orientalsniper]

Hello, I could use some help trying to fix this motherboard, so I get 3.4V in PWRSW and I also shorted the PSU to feed power to motherboard by force and I don't feel any heated part.

Could the problem be in the SIO chip or southbridge/northbridge?

UPDATE:

Only 5V in PIN9 (+5VSB) and 5V in PIN16 (PSU_ON#) of PSU connector.

[ReeceyBurger123]

Re: ASRock Z77 Extreme 6 not powering up

Lets rule out the psu first, do you have another psu to check the board with ?

[orientalsniper]

Re: ASRock Z77 Extreme 6 not powering up

Yeah, I've tried different PSU/processor/RAM.

[ReeceyBurger123]

Re: ASRock Z77 Extreme 6 not powering up

Ok sounds like something on the board, firstly check the board all over for any shorted pins for example on the pci slots if there is nothing obvious then I will tell you what to check next.
Also check things like the usb ports and ram slots, we need to narrow this down.

[orientalsniper]

Re: ASRock Z77 Extreme 6 not powering up

Yeah, man, I already checked those: USB, SATA, Firewire, LAN, HDMI, PCI, PCIe, RAM.

[orientalsniper]

Re: ASRock Z77 Extreme 6 not powering up

Checking resistance with ATX power connector against ground:

3.3V: 265 ohms
5V: 515 ohms
12V: 3 kohms

[ReeceyBurger123]

Re: ASRock Z77 Extreme 6 not powering up

Sounds like a short, firstly check the cpu vrm mosfets as they normally go first check all the mosfets for resistance just check them all and see if any of them check different from the majority of them.

[orientalsniper]

Re: ASRock Z77 Extreme 6 not powering up

Sorry, what do you mean by resistance? Gate/Source/Drain against ground?

I did test the coils near the vrm mosfets and so far it's not shorted against ground though.

[david38c63]

Re: ASRock Z77 Extreme 6 not powering up

I would start looking for bad caps that esr is too high on in the 3.3v supply and 5 volt stand by