I'm pretty new to raspberry pi, and it always used to work fine, but I've got a new monitor, the BenQ GW2270, and I set my raspberry pi 4 up using the micro-hdmi to my monitor's hdmi port, and when I switched it on, I saw the rainbow coloured switching on screen, but then it just went black for a few seconds, then my monitor just said no signal, and I don't know why. Thanks for helping!


2 Answers 2


Try the following:

  • Add hdmi_force_hotplug to /boot/config.txt
  • Add hdmi_safe=1 to /boot/config.txt
  • Use the old monitor to change the resolution to 640x480 and frequency of 60.00Hz (through Screen Configuration)
  • Make sure you are using the HDMI closest to the power input
  • If possible, plug the old monitor into the first HDMI and the new one into the second HDMI and see if they both display stuff.

Hope this helps you fix the problem.


If possible find another linux device and connect that sdcard with that PC. Then go for config.txt and uncomment the the hdmi_safe=1. This could fix the hdmi output.

  • 1
    You can use Windows devices too as they can see the boot partition.
    – dominic03
    Jul 15, 2020 at 16:06

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