Diagnosis
The USB-C port on the BenQ EW3270U is not a video input port; it is a service port for firmware updates and factory servicing. Your MacBook cannot send a video signal to it, which is why you get "no signal."
How to Fix It
To connect your MacBook, you must use one of the monitor's dedicated video inputs. Follow these steps:
- Identify the video ports on your specific MacBook (e.g., USB-C/Thunderbolt).
- Obtain the correct physical adapter or cable: a USB-C to HDMI cable or a USB-C to DisplayPort cable.
- Connect the USB-C end to your MacBook and the other end (HDMI or DisplayPort) to the corresponding port on the back of the EW3270U.
- Power on the monitor and your MacBook. The monitor should automatically detect the signal. If not, proceed to the next step.
If That Didn't Work
If you still have no picture, manually select the correct video source on the monitor.
- Press the 'Source' button on the monitor's bezel or remote control.
- From the on-screen menu, select either 'HDMI 1', 'HDMI 2', or 'DisplayPort'—whichever matches the cable you used.
- Also, try a different video cable or adapter to rule out a faulty accessory. Test the MacBook on another display to confirm it is outputting video correctly.
Heads Up
The USB-C port on this monitor will never function for video. Always check the port labels: for video input, you must use only the HDMI 1, HDMI 2, or DisplayPort ports located in a separate cluster on the back panel.