the monitor says 'check signal cable' but my pc is on and the cable is plugged in.

Diagnosis

The "Check Signal Cable" error on the Samsung Odyssey G7 (LC32G75T) occurs when the monitor's internal logic board fails to detect a handshake signal from the GPU. While this often looks like a dead cable, it is frequently caused by "Input Auto-Switching" failure, where the monitor remains locked on a dormant port (like HDMI) while your PC is sending data via DisplayPort. Because the G7 supports high bandwidths (up to 240Hz), any slight voltage drop or timing mismatch in the handshake process causes the monitor to default to this error message rather than attempting to sync. Another common root cause is a "Refresh Rate Mismatch." If you recently updated your NVIDIA or AMD drivers or changed your Windows Display settings to 240Hz, but your cable is a lower-spec HDMI or an older DP 1.2 cable, the monitor will fail to sync the signal. The monitor doesn't see a "bad" signal; it sees "no" signal because the data stream is corrupted by the bandwidth limitation, triggering the "Check Signal Cable" prompt even though the hardware is physically connected.

How to Fix It

To resolve the handshake failure and force the monitor to recognize your PC, follow these precise steps:

1. Locate the JOG button (the small joystick) centered on the bottom edge of the monitor bezel.
2. Press the center of the joystick to bring up the On-Screen Display (OSD) menu.
3. Move the joystick to the right to access the "Source" menu.
4. Manually toggle through the options. If you are using a DisplayPort cable, explicitly select "DisplayPort." Do not rely on "Auto," as the G7 often hangs on the wrong port.
5. Once selected, press the center of the joystick to confirm.
6. If the screen remains black, perform a "Hard Power Cycle": Unplug the power cable from the back of the monitor AND the power outlet. Hold the power button (joystick) down for 15 seconds to discharge the capacitors. Plug it back in and restart the PC.
7. Boot into Windows. Right-click the desktop, select "Display Settings" > "Advanced Display," and ensure the refresh rate is set to 144Hz first. Once you have a picture, you can attempt to bump it up to 240Hz.

If That Didn't Work

• Reseat the GPU: In high-end gaming rigs, the weight of the graphics card can cause "GPU Sag," which slightly pulls the DisplayPort pins out of the PCIe slot. Power down the PC, remove the GPU from the motherboard, blow out the slot with compressed air, and reseat it firmly. Ensure the locking clip clicks into place.
• Swap to a VESA-Certified DP 1.4 Cable: The LC32G75T is notoriously picky about cable quality. Cheap "Amazon Basics" or bundled cables often fail at 240Hz. Purchase a VESA-certified DisplayPort 1.4 cable with a bandwidth of 32.4Gbps. Avoid cables longer than 6 feet (2 meters), as signal degradation occurs rapidly at high refresh rates.
• Disable CSM in BIOS: Enter your motherboard BIOS (usually by tapping Del or F2 during boot). Navigate to the "Boot" tab and disable "CSM" (Compatibility Support Module). Enabling UEFI mode ensures the GPU sends a modern signal that the Odyssey G7 can recognize during the initial POST sequence.
• Test the "Cold Boot" Sequence: Some G7 units have a bug where they won't wake from sleep. Turn the monitor on first, wait for the "Check Signal Cable" box to appear, and then boot the PC. This forces the monitor to be in "Listening Mode" when the GPU sends its first handshake.

Heads Up

• Avoid HDMI for 240Hz: While the monitor has HDMI ports, you will almost never achieve the full 240Hz refresh rate or G-Sync/FreeSync stability over HDMI on this specific model; always prioritize DisplayPort.
• Firmware Updates: Check the Samsung support site for firmware updates for the LC32G75T. Many "No Signal" bugs were patched in later firmware versions via the USB service port on the back.
• Avoid Power Strips: Plug the monitor directly into a wall outlet. High-draw gaming PCs and 32-inch curved panels can cause voltage dips in cheap power strips, leading to intermittent signal loss.
• Check for Pin Damage: Inspect the DisplayPort connector for bent pins. Because DP cables have locking latches, forcing them out without pressing the release button can bend the pins, causing the "Check Signal Cable" error.