New
#1
RMA’d Mobo and CPU, CPU diagnostic light always on, no BIOS/boot loop
Hi all, first time poster. Recently I bought upgrade parts for my existing computer: A Ryzen 9 3900X and a Gigabyte X570 Aorus Pro Wifi. I’m switching from Intel to AMD. I got the motherboard used, and the 3900X new, both from B&H. I install all the parts, and lo and behold, I can’t get anything. The CPU diagnostic light is lit, and there is no output from the card. After troubleshooting, I figured it was a defective used board and returned the board back to B&H. A week later, I got a new board back. Same issue. I’m about to return both board and CPU when I managed to use the Q-Flash feature on my motherboard and update to the latest bios. I return the CPU only. Today, I get the replacement CPU. Same issue again. No matter what, as long as the CPU is inserted and power is on, the CPU diagnostic light is on. After starting, the front panel buttons no longer work (power, reset), and I have to turn off the PSU to shut it down. Fans spin, but I cannot get past the CPU diagnostic light at all. There is a chipset fan that comes on every startup, but is supposed to stop after successful POST. My chipset fan stays running at full speed. The behavior is the same from one mobo to next, and one CPU to the next. I’ve tried many different configurations.
Completely bare bones (everything out), with only CPU and power. CPU light is on.
Dual RAM, single RAM, single RAM tried in every slot. CPU light is on.
Tried different PCIe slots for the GPU and removing the GPU. CPU light is on.
Cleared the CMOS. CPU light is on.
Tried without a cooler briefly to ensure mounting pressure wasn’t too high. CPU light is on.
Tested PSU with paperclip test. PSU Working.
It’s sitting on a cardboard box right now, with the PSU also removed from the case. CPU light is on.
Flashed updated bios. CPU light is still on.
M.2 and SATA slots are all empty.
I swear I’ve completely exhausted my options and I’m about to give up. Any advice?
I should note that when I tried it without the cooler, I was feeling the surface of the CPU lid and it was getting warm. So something was definitely happening inside there. But alas, the light stayed lit, even after allowing 10 minutes for the computer to run (because I read that new motherboards might need more time to index RAM).
Specs are:
EVGA Supernova G2 750 Gold
Ryzen 9 3900X
Gigabyte X570 Aorus Pro Wifi (REV1.1, then REV1.2)
Micron (Ballistix brand) DDR4-2666, 2x 8GB, BLS8G4D26BFSEK.8FD
MSI R9 390, using DVI output
Windows version would be Windows 10 Pro 20H2, if only I could get into my computer first![]()