I'm troubleshooting a system with a Ryzen 5 5600, MSI RTX 3070 Ti, MSI MAG B550 Tomahawk, 2×8 GB Ballistix Sport DDR4-2666, a Noctua NH-U12S Redux cooler, and a be quiet! Pure Power 12M 750 W PSU. The Ryzen CPU had several bent pins, which I carefully straightened before installing it. The cooler was initially installed with thermal paste and connected to CPU_FAN. When I power on the system, the case fans and GPU lighting/fans start, and the motherboard's debug LEDs eventually turn off, but the monitor still reports no signal. The display cable is connected directly to the graphics card, and I've checked the 24-pin, CPU 8-pin, and GPU power connections, cleared CMOS, and reseated the graphics card. Could this be an outdated BIOS, a damaged CPU pin, incorrect cooler pressure, or something else? The motherboard has a BIOS Flashback button, so I'm also wondering whether I can update the BIOS without another processor.
3 Answers
Clear CMOS again with the power supply switched off and unplugged, then try a minimal setup: motherboard, CPU with cooler, one RAM stick, GPU, and the PSU. Disconnect storage and extra USB devices. Check that the CPU power cable is connected to the EPS/CPU socket rather than a PCIe socket, and try another PCIe power cable or monitor input if available. If it still gives no display after a BIOS Flashback and careful pin inspection, the CPU or motherboard may have been damaged during the original bent-pin issue.
The B550 Tomahawk supports BIOS Flashback, so you should be able to update the BIOS without borrowing another CPU. Download the correct BIOS file, rename it as required by MSI, put it on a FAT32 USB drive, and use the Flash BIOS port and button exactly as described in the manual. Also make sure the motherboard’s CPU and VGA debug LEDs are not staying lit; briefly turning on is normal during POST.
The CPU is the main concern because AM4 pins are on the processor. Check for pins that are still bent, touching neighboring pins, or broken off, and confirm the CPU drops into the socket without force. Reseat the RAM as well, then test with one stick in the slot recommended by the manual. If possible, test with the graphics card removed only for inspection—the Ryzen 5 5600 has no integrated graphics, so the monitor must remain connected to the RTX 3070 Ti.
Don’t run the system without the CPU cooler installed. It may shut down quickly from overheating, and testing that way can damage the processor. Use a small amount of new thermal paste and mount the cooler evenly, without overtightening it.
A BIOS update is worth trying, but it won’t fix a CPU with a broken or badly misaligned AM4 pin. Remove the processor and inspect every pin carefully under bright light before flashing anything.