Question New PC posted once, now fails to boot with amber VGA LED on motherboard.

[daylen007]

Just finished building my PC. When I had everything tucked away, I powered it on and made it to the BIOS screen. I powered it off, cleaned up the table a bit, plugged in my mouse, keyboard, and USB to update the BIOS, powered it on and now I get the amber VGA debug LED on the motherboard. All fans spin on startup, GPU and PSU fans stop after a bit. Maybe normal?

Part List:

• GIGABYTE Z790 UD AC D5
• INTEL I9-13900K
• GIGABYTE RTX4080 AERO OC
• CORSAIR 32GB VENGEANCE DDR5 6000 C40 BL
• SAMSUNG E 2TB 970EVO+NVME M.2 SSD
• TOSHIBA 6TB X300 7200RPM 3.5 HDD
• CORSAIR RM1000E FM 80+G ATX3 PSU

Things I've tried:

• Boot without GPU installed
• Boot with NVME installed
• Boot without HDD plugged in
• Boot with single RAM stick in A2 (tried both sticks)
• Boot with HDMI plugged into motherboard
• Boot with HDMI plugged into GPU
• Clear CMOS pins for 10 seconds
  • When I shorted the CMOS_CLR pins, the DRAM lights up for a bit and turns back off. Not sure if that's normal.
• Unseat battery for 10 seconds and reseat
• Checked PSU cables
• Different PCIe slot.

Nothing has gotten me back to BIOS. Thoughts on what it could be or what to try next?

Initial Post

 

[helpstar]

reflash the bios

did you do the cmos reset while power was unplugged? power has to be off from the wall

 

[daylen007]

refpash the bios

did you do the cmos reset while power was unplugged? power has to be off from the wall

How do I reflash the bios without being able to access it? In the manual, I see there's a button to do it, but that button has to be enabled as an option in the BIOS.

Yes, the power was off and unplugged when I cleared the CMOS.

 

[daylen007]

Found out how to reflash bios without needing to be able to get to BIOS first. Did not resolve the issue. At this point I imagine I need to determine if it's the CPU or the motherboard. Any way to do that without a dedicated test bench?

 

[helpstar]

which bios version did you flash? F7 is the latest
are you sure that the BIOS update was running ?

disconnect and reconnect all connectors and devices

 

[daylen007]

Version F8. Came out a few days ago. The LED next to the flash button was blinking and the PC turned on when it was finished. I have no visibility to if it successfully updated or not though.

I've stripped it down and re built it, yeah.

 

[daylen007]

UPDATE: It's fixed! After replacing both the motherboard and CPU, still would not post. Out of pure curiosity I switched to a different monitor and it posted just fine. Not sure if it was some weirdness with the monitor not responding to whatever VGA check the motherboard was doing, but I'm up and running now.