Most no signal error reports tied to a 240Hz monitor come down to a cable that cannot carry 240Hz or a wrong refresh-rate setting. Confirm the simple things first before assuming a faulty part.

Quick Answer

Yes, a no signal error on a 240Hz monitor is usually a quick fix: plug the monitor into the graphics card, swap the cable, and reseat the RAM and GPU. Start with that the DisplayPort 1.4 cable is rated for 240Hz and that Windows refresh rate is set to 240Hz before spending money on replacements.

First Checks for Your 240Hz monitor

Confirm the monitor is set to the correct input and the cable runs to the graphics card, not the motherboard, on any build with a dedicated GPU. For a 240Hz monitor specifically, confirm that the DisplayPort 1.4 cable is rated for 240Hz and that Windows refresh rate is set to 240Hz. A HDMI 2.0 cable often caps a 1080p panel at 144Hz, so use DisplayPort for the full 240Hz.

Drivers, Firmware, and Software

If the system posts but stays blank in Windows, boot to safe mode and reinstall the GPU driver with DDU. On a 240Hz monitor, set the monitor refresh rate in Windows Display Settings and the GPU control panel to 240Hz. A clean driver reinstall using DDU often clears display faults that survive a simple reboot.

Isolate the Faulty Part

Reseat RAM one stick at a time and clear CMOS to rule out memory and BIOS faults. Swap one variable at a time so you know which part of the 240Hz monitor chain is at fault. Try a second DisplayPort cable and a different port to rule out the cable before the panel.

FAQ

Why does my 240Hz monitor say no signal?

No signal means the display gets no valid input: confirm that the DisplayPort 1.4 cable is rated for 240Hz and that Windows refresh rate is set to 240Hz. A cable that cannot carry 240hz or a wrong refresh-rate setting is the usual cause and is fixable without new parts.

Should I plug the monitor into the GPU or motherboard?

Always the graphics card on a build with a dedicated GPU. Using the motherboard output on such a system is a top no-signal cause.

Can the wrong cable cause a no-signal error on a 240Hz monitor?

Yes. An underspecced or faulty cable is common. Try a different DisplayPort or HDMI cable and a different port before suspecting the 240Hz monitor.

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