New Build issues

John_Canb · September 15, 2021

Hi All

Apologies if this has been asked already, trawled through posts and couldn't see anything that helped, this is my first build, most likely something I am missing but I cannot pin point it, apologies in advance if I have missed anything.

New build is confusing me, when all power connected ATX 24 Pin and 8 Pin CPU PC will not power on, no lights no CPU Fan spin, nothing, dead, and red light under 4 pin CPU Power header(sit next to 8pin).

When I disconnect the 8pin CPU power everything spins up RGB on CPU Fan, RAM and GPU all spin to life, but wont post, red light remains under 4pin CPU header.

I have split the 8pin into 4+4 and connected to the 4 pin, same result - no boot, no lights nothing.

I have undertaken the following with same result with no CPU Power connected

According to MOBO manual I need 24 pin + 8Pin connected, i believe the 4 pin CPU is only for extreme overclocking

Device Boots but will not post

-removed everything from case and set up breadboard test bed (no case fans) but still connected to case front panel.

-Reseated RAM

-Checked 24pin

-Removed RAM and tested each stick individually

-Tested with a old (but known working) PSU, same result.

-same result with brand new PSU (SF750)

-removed everything from case and set up MOBO as breadboard test bed

-tried multiple CPU power cables

-Removed and tried GPU into another PCIE slot

-tried different monitor - both work with other PCS

-Tired multiple inputs and cables (display and DP) both connections on GPU and changed input on monitor.

-Attempted to update BIOS (unsure of current BIOS version) but not sure if updated, BIOS Flash indicator didn't flash but appeared to be reading USB for 5ish minutes

-No error LEDs (Boot, RAM,SPU etc...)

I'm leaning towards an issue with MOBO, but cant rule out CPU, all hardware is new from retailers (not some hack on E-Bay).

I did previously have a faulty PSU from the box, so when PSU was sent back i also sent back MOBO and it was confirmed as working fine.

Anyone have any suggestions as to what i can try next.

Image of Red LED under 4PIN