My PC powers on and all the fans spin, but the monitor suddenly reports "No video input" and enters standby mode. If I unplug the DisplayPort cable, the monitor correctly detects that the cable is disconnected, so it still appears to be functioning. I tried different ports on the graphics card, an HDMI cable, another monitor, and connecting the monitor to another computer. The monitor worked with the other computer, which points to a problem with my PC rather than the display. I also tried the motherboard video output, though this system uses an Intel Core i5-12400F, which does not have integrated graphics. The computer had worked normally for about three years. What hardware should I check, and is the likely failure the graphics card, motherboard, or something else?
2 Answers
Since the monitor works with another computer and a second monitor also fails on this PC, the issue is probably inside the PC. Power it down, unplug it, remove the graphics card, then firmly reinstall it in the PCIe slot. Also disconnect and reconnect every PCIe power connector on the card. A card can gradually sag or lose good contact in the slot, especially after years of use. A support bracket can help prevent it from happening again.
It’s still worth confirming the monitor is set to the correct input and testing another known-good cable or display. Some monitors stay locked to an input that no longer has an active signal. However, because another monitor also failed with this computer, those checks are less likely to be the underlying problem. Also, the motherboard video ports won’t produce an image with an i5-12400F because that processor has no integrated graphics.
That solved it. I removed and reseated the graphics card and reconnected its PCIe power cables, after which the display came back. I’m going to add a GPU support bracket as well.