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I just bought two raspberry 4s (1Gb and 2Gb of RAM) and am unable to get the slightest video signal out of them. I tried every combination of the following components:

  • Raspbian buster lite/desktop

  • 5V 3A USB-C power supply / 5V 3A micro-USB with USB-C adapter

  • Amazon Basics micro HDMI cable (mentioned as compatible on the raspberry website) / GoPro compatible micro HDMI cable (by JVC)

  • two different 7 inch touchscreens / a desktop screen (all three work fine with pi 3s)

  • Using HDMI ports 0 and 1

NONE of these produced any image, just a "no signal" on the display. The PI appears to boot normally with the green LED blinking intensively at first. Now I'm tempted to conclude that my raspberry's are defective but they are from two different vendors and the chances of that seem minuscule.

The config.txt has every line commented, except a few near the end :

# Enable audio (loads snd_bcm2835)
dtparam=audio=on

[pi4]
# Enable DRM VC4 V3D driver on top of the dispmanx display stack
dtoverlay=vc4-fkms-v3d
max_framebuffers=2

I can SSH into the PI but I see nothing unusual in the syslog. With my desktop screen on port 0, running "tvservice -l" gives me:

1 attached device(s), display ID's are :
Display Number 2, type HDMI 0

Running "tvservice -s -v 2" gives me the output:

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

So if anyone could suggest other things to try I would greatly appreciate it.

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  • First thing first is to remove the two different 7" touch screens. There is 50% chance that the old stretch driver won't work with buster.
    – tlfong01
    Commented Jul 27, 2019 at 1:08
  • post the content of your config.txt file
    – Jaromanda X
    Commented Jul 27, 2019 at 9:37
  • @JaromandaX I've updated the question
    – schmop
    Commented Jul 27, 2019 at 17:22
  • @tlfong01 I'm now only testing on a fresh raspian buster install and on a regular HD screen (that works fine on my pi 3s)
    – schmop
    Commented Jul 27, 2019 at 17:24
  • enable ssh, ssh into the pi with the monitor connected, and check the logs for any errors. and check tvservice -l - then using the two display numbers (2 and 7?) what's the output of tvservice -s -v 2 and tvservice -s -v 7
    – Jaromanda X
    Commented Jul 28, 2019 at 2:23

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