I replaced my motherboard and power supply after my computer suddenly shut down and later showed no display with the CPU debug light lit. The old motherboard was refurbished, so I installed a brand-new ASRock X870 Steel Legend WiFi along with the new PSU. On the first startup, the CPU light stayed solid red and the DRAM light flashed yellow/orange. After letting it run for about 15 minutes, the DRAM light turned off but the CPU light remained red. I'm wondering whether the system is still training the memory or if there's a problem with the CPU, wiring, RAM, or motherboard. What should I check before replacing the processor?
3 Answers
Clear the CMOS, then test with one memory module in the slot recommended by the manual, usually A2. Try each stick separately if you have more than one, and wait a few minutes after each power-on for training. Disconnect drives, USB devices, and other expansion cards while testing. If it still stops at the CPU light, update the board BIOS using its flashback feature if available, then test with the CPU and cooler reseated.
Start with a minimal test outside the case. Place the motherboard on its box or another nonconductive surface and connect only the CPU, CPU cooler, one RAM stick, the graphics card if your processor has no integrated graphics, and the PSU. This rules out a misplaced motherboard standoff or a screw causing a short. Also make sure the 24-pin motherboard cable and the 8-pin CPU/EPS cable are fully connected. Do not use a modular cable from the old power supply with the new one.
On a new AM5 system, the first boot can take several minutes while the memory trains, especially after clearing CMOS or changing RAM. An hour usually isn’t necessary, though. If the DRAM light goes out and the CPU light stays red, shut it down and reseat the CPU, inspect the socket for bent pins or debris, and reinstall the cooler evenly without overtightening it. Verify that the CPU is supported by the installed BIOS and that the EPS cable is plugged into the CPU power socket rather than a PCIe socket.
After about 15 minutes the DRAM light turned off, but the CPU light stayed solid red, so I’ll focus on the CPU seating, socket, cooler pressure, and BIOS compatibility.
I’m not familiar with testing it outside the case, but the board is a new ASRock X870 Steel Legend WiFi and it does power on. I’ll check the standoffs and try a minimal setup.