[SOLVED] New Desktop - CPU light blinks once, fan doesn't start

[provedor001]

Hi folks,

First time building a desktop here and I'm having trouble starting it off. I've read through the troubleshooting
https://forums.tomshardware.com/thr...ng-about-post-boot-no-video-problems.1285536/

And checked all the items except (since it's not even booting):

• Did you install the system speaker
• Is your CPU supported by the BIOS revision installed on your motherboard
• Re-setting CMOS
• Don't have a working PSU to test if it is at fault - will take machine to a repair shop later this week to see if they can test for me.

Here are more detailed symptoms:

• Motherboard lights are on when I turn the PSU on
• Once I hit the power button:
  • CPU led on motherboard blinks for 0.1s.
  • The CPU fan starts off only for 0.1s too.

Things tried so far:

• Tested with 2, 1 RAM in different slots. Tested with 0 RAMs, always the CPU light that goes off
• Moved Motherboard outside the case (anti-static mat)
• Verified that CPU doesn't have any bent/damaged pins
• Verified that the 24-pin ATX is connected to the PSU
• Verified that the 8 ATX_12V_2X4 is connected to the PSU
• Verified that the CPU fun is connected to the motherboard (CPU_FAN pins)

Specs:

All brand new components purchased on Amazon

• Motherboard: Gigabyte Z390 Gaming X
• CPU: Intel i5 8400 LGA1151 (8th gen)
• RAM: Aegis DDR4 16GB ((PC4 19200) Intel Z170/X99 Platform Desktop)
• PSU: Seasonic, 650W, 80 Plus Gold

Any other ideas before I pay a visit to the repair shop and look into returning the motherboard / PSU / CPU?

Thanks!

 

[Calvin7]

Motherboard power connectors:

• 1 x 24-pin ATX main power connector
• 1 x 4-pin ATX 12V power connector
• 1 x 8-pin ATX 12V power connector

The manual shows the 8-pin ATX power connector can possibly be connected using only 4-pins. It appears you didn't read the manual and didn't connect the 4-pin ATX 12v power connector.

you wrote:

• Verified that the 24-pin ATX is connected to the PSU
• Verified that the 8 ATX_12V_2X4 is connected to the PSU

 

[provedor001]

Not sure I follow, do you mind clarifying? The cable coming out of the PSU has 8 pins:

It's not clear from the manual that I need to connect the 4-pin one:

This post also mentions that connecting only the 8-pin one is enough: https://forums.tomshardware.com/thr...n-of-4-pin-and-8-pin-power-connector.3416104/

 

[Theworstluckistg]

Had this problem a while back, be very very careful. When I hooked up my old PSU my hard drive was cooked. Try with a different power supply, but unfortunately the damage is probably already done and the power supply was likely dead on arrival. Also that 8-pin you're holding is the CPU plug, should fit somewhere around the CPU fan plug. 4 pin connectors are for older CPUs, so if you have an 8-pin slot the 4-pin is unnecessary.

 

[provedor001]

Thanks for following up. Your hunch is right, it was the PSU. I went to the repair shop and they tried with a different one and the system booted, so luckily no damage so far.
I just got a repl