I took my PC apart while waiting for a replacement part, and after putting it back together it powers on but never reaches POST or displays an image. The fans spin, and the keyboard and mouse light up. I've removed and reseated the components twice, tried different RAM configurations, reset the CMOS battery, tested every display output, and double-checked all cables. The system has an ASUS Prime B450M-K motherboard, Ryzen 5 3600X, RTX 4070, 16GB of DDR4 memory, and a GX-850 power supply. There's a constant orange glow near the GPU slot, although that light was also present when the computer worked normally. What else should I check?
2 Answers
Since the problem started immediately after reassembly, also check for a case-related short. Make sure the motherboard is sitting only on the correct standoffs and that no screw or loose metal part is touching the underside. Try starting it outside the case on the motherboard box, using a screwdriver across the power-switch pins. It’s also worth loosening the motherboard or power-supply mounting screws slightly if they were tightened excessively; pressure or misalignment can sometimes prevent POST.
The orange light may just be the motherboard’s normal standby illumination, since the Prime B450M-K doesn’t appear to have the full set of diagnostic LEDs. Because the Ryzen 5 3600X has no integrated graphics, make sure the monitor is connected directly to the RTX 4070. Also verify the CPU EPS power connector at the top of the motherboard and the GPU power adapter are fully seated. If needed, test with only the CPU, cooler, one RAM stick, GPU, and the two main power connectors attached.
Loosening the power-supply mounting screw slightly fixed it, and the PC posted again. Thanks!