Rasberry Pi 4 and No Signal on some monitors

  • Hi,

    New to Kodi and LibreELEC, not new to Linux. I purchased a Pi 4 to run Kodi on and I am really struggling with most monitors/TVs not detecting HDMI signal. I can unplug from one monitor at my desk to another and the display is fine. The monitor I'm using to get Kodi up does not work nor does the TV that I will eventually use. If I use my RPi3, the same monitor works fine.

    This tells me:

    • the HW is working
    • the cable is good
    • LibreELEC and Kodi are up and running
    • the monitor is not the issue

    I've made changes to the config.txt to force modes and hot plug, etc., but nothing is working and I need some more ideas. What more info would is needed to help me troubleshoot and solve this? I'm not seeing any errors in my log file other than freedesktop.UPower service file not existing. What tvservice output would be helpful, if any, for me to provide?

    Thanks!

    Mike

  • Hi Da Flex,

    Thanks for responding.

    Yes, I have tried hdmi_safe=1 and both HDMI sockets. I also have hdmi_force_hotplug=1. Even when the monitor shows no signal, I disconnect the cable from the monitor and connect it to a different monitor, it works fine. I'm guessing the monitor is not sending the right data to tell the Pi what mode to use.

    Here is what tvservice -m CEA shows:

    Here is the status:

    Code
    tvservice -s
    state 0xa [HDMI CUSTOM RGB lim 16:9], 1920x1080 @ 60.00Hz, progressive

    I just did a tvservice -n and it shows the model number of the monitor that it's connected to. So there is communication.

    Code
    tvservice -n
    device_name=VIZ-E241i-B1

    I saw a page somewhere that I can't find anymore where I hardcoded modes and resolutions into config.txt and it didn't help. I don't know the tvservice command at all so I don't know if the output above is what's reported from the monitor or if it's what the Pi supports.

    I am using a case that routes the ports to the back of the case, and I have tried direct connecting. Since it works on another monitor, then it must be something in how monitors are communicating with the Pi.

    Other suggestions?

    Thanks,

    Mike

    Edited once, last by loveridgem: Added tvservice -s Added tvservice -n (November 25, 2020 at 11:48 PM).

  • Try this config.txt (enforces CEA mode 16):

    Those settings work for many users with older monitors.

  • No joy on using the config you gave above. :(

    I'm going to try Pi OS and maybe Pi Ubuntu to see if it's some odd driver issue. I see that this seems to be a common theme for Pi 4 users. I can try the official OS and if it doesn't work, I can follow the troubleshooting there. It may lead me to a solution for LE.

    Thanks!

    Mike

  • Yes, I'm at a complete loss on this. I'll try the color spaces later today.

    What I have learned is the tvservice is returning the name of the monitor and its resolution. So there is communication and it should be showing me something. But I get nothing. Even during the basic boot to a new OS. I never see the Pi color splash before the OS loads.

    I would think it was this one specific monitor, but it doesn't show on the TV either which would be CEA versus DMT. The fact it works on my Acer monitor leaves me scratching my head and really bummed the Pi 4 is having these issues.

  • I also experiment the same issue using a new Smart TV Philips 43UPS8505.

    When Libreelec9.2.6 boots on Pi4, I only see on the TV the name `Kodi` next to the HDMI port 1 but nothing will be displayed and theTV finally reports "Please check the HDMI connection or HDMI parameters of the HDMI source. The cable is plugged to the HDMI port of a Pi4

    Here is my config.txt