I have a Pi connected to a Polaroid tv by HDMI cable in order to create a "Dakboard".

Now when initially starting the project the TV was acknowledging a signal coming from the HDMI port (ie the no signal error message disappeared) but the screen remained black. This was easily solved by uncommenting the "hdmi_force_hotplug=1" and "hdmi_drive=2" lines in the boot/config.txt file, the pi was now displaying on the tv.

I have now however added a crontab job (following the tutorial linked below) to turn the display off at a certain time then back on at a certain time by enabling and disabling the HDMI port. The port is disabled as desired at the correct time therefore leaving me with a "no signal" display on the tv, however when it's time to enable the port again the "no signal" message disappears but nothing is displayed, it's just a black screen.

My guess is that this is the same issue as when I initially started and that I somehow need to add the "hdmi_force_hotplug=1" and "hdmi_drive=2" into the crontab run .sh file.

If anyone has any suggestions I'd be keen to hear them. The tutorial I have built this using is linked here;


  • May be a bug with the script for your setup at least -It could be a hardware issue, I have heard TVs are more weird about inputs that monitors so are more likely to be annoying. Anyway (in case its not annoying hardware), can you try running the turning on command /home/pi/rpi-hdmi.sh on (via a console like SSH) please - it may give useful information if its failing somewhere (e.g. due to lacking privileges) – Wilf Jun 16 '18 at 23:32
  • are you sure that you do not have a screensaver running that displays a black screen? – jsotola Jun 17 '18 at 0:25

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