A few months ago, an RTX 4090 began showing artifacts and eventually stopped producing any video output. The motherboard's VGA diagnostic LED came on, and the 4090 was later tested in a workshop and confirmed to be dead. The power supply was also tested in another computer and worked properly. After leaving the system unplugged for about two months, I installed a new RTX 5080, but the monitor still shows no signal. I reseated the GPU and its power connectors, tried different display cables, reseated the RAM, and reconnected the CPU power cables. This time, the motherboard's red VGA LED does not light up, but the system still does not display anything. The CPU is a Ryzen 7 5800X3D, so there is no integrated graphics output to test. Could the motherboard or another component have been damaged, and what should I check next? The issue was eventually fixed by replacing the motherboard battery.
2 Answers
Testing the PSU in another working computer is a much better check than simply seeing whether it turns on, so that makes the power supply less suspicious. Since the original 4090 was also confirmed dead separately, the remaining possibilities were the motherboard, its settings, or damage caused when the first card failed. A CMOS reset and fresh battery would be sensible steps, followed by checking motherboard power, RAM, and boot diagnostics.
Since the 5080 no longer triggers the VGA light, the graphics card may be initializing correctly and the problem could be elsewhere. Because the Ryzen 7 5800X3D has no integrated graphics, you can’t use the motherboard video ports to test for a successful boot. Clearing the CMOS or replacing the motherboard’s CR2032 battery is worth trying before assuming the board is dead.
I replaced the motherboard battery, and that solved the problem. The system is displaying normally now.