lolalola
Posts: 9
Joined: Tue Aug 02, 2022 1:19 pm

No HDMI signal - RPI 4 model B

Wed Aug 03, 2022 1:47 pm

Hi,
I've been using a Raspberry Pi 4 model B as a desktop computer for about a year now, and there's been a lot of trouble with the HDMI signal ever since I got it. At first I couldn't get any picture from the Pi whatsoever, then I somehow got it to work by editing the config.txt. Then there's been periods when the screen has been flashing on and off A LOT, and some periods where it's been working perfectly fine. The screen has also been flashing every time any lamp or device in my home is turned on (?).
The other day it stopped working again completely, I just get a "NO SIGNAL" message on the monitor. I've tried using both a DVI-D monitor (with an adapter) and a HDMI TV. I've tested two HDMI cables.
I've also tried to edit the config.txt but it doesn't seem to help.
The red light on the Pi is steadily on.
Does anybody know what the problem might be?
Thanks

aBUGSworstnightmare
Posts: 5632
Joined: Tue Jun 30, 2015 1:35 pm

Re: No HDMI signal - RPI 4 model B

Wed Aug 03, 2022 2:11 pm

lolalola wrote:
Wed Aug 03, 2022 1:47 pm
Hi,
I've been using a Raspberry Pi 4 model B as a desktop computer for about a year now, and there's been a lot of trouble with the HDMI signal ever since I got it. At first I couldn't get any picture from the Pi whatsoever, then I somehow got it to work by editing the config.txt. Then there's been periods when the screen has been flashing on and off A LOT, and some periods where it's been working perfectly fine. The screen has also been flashing every time any lamp or device in my home is turned on (?).
The other day it stopped working again completely, I just get a "NO SIGNAL" message on the monitor. I've tried using both a DVI-D monitor (with an adapter) and a HDMI TV. I've tested two HDMI cables.
I've also tried to edit the config.txt but it doesn't seem to help.
The red light on the Pi is steadily on.
Does anybody know what the problem might be?
Thanks
bad cable or adapter is the most often root cause for such, followed by wrong EDID send by monitor.

What is the resolution of your monitor? Are you able to connect to your Pi via SSH (to figure out if it's booted at all)?

lolalola
Posts: 9
Joined: Tue Aug 02, 2022 1:19 pm

Re: No HDMI signal - RPI 4 model B

Wed Aug 03, 2022 3:42 pm

Okay, I also thought the adapter or cable was the problem but then I tested it with the TV and it still didn't work despite not using an adapter. I guess the HDMI cables could be bad, they both came in the RPI kit. The resolution of my monitor is 1680 x 1050.
How do I know if wrong EDID is sent by the monitor?
I haven't tried to connect via SSH because I don't know how to do that, will try as soon as I figure it out!

aBUGSworstnightmare
Posts: 5632
Joined: Tue Jun 30, 2015 1:35 pm

Re: No HDMI signal - RPI 4 model B

Wed Aug 03, 2022 4:29 pm

lolalola wrote:
Wed Aug 03, 2022 3:42 pm
Okay, I also thought the adapter or cable was the problem but then I tested it with the TV and it still didn't work despite not using an adapter. I guess the HDMI cables could be bad, they both came in the RPI kit. The resolution of my monitor is 1680 x 1050.
How do I know if wrong EDID is sent by the monitor?
I haven't tried to connect via SSH because I don't know how to do that, will try as soon as I figure it out!
hmm, would start with a test first, swiching back to FKMS

Force 1680x1050 resolution by adding below to config.txt (in boot directory, you can do that on your PC/MAC as well or via SSH on the Pi.

Code: Select all

hdmi_group=2
hdmi_mode=58
search config.txt for the line 'dtoverlay=vc4-kms-v3d' and change to

Code: Select all

dtoverlay=vc4-fkms-v3d
save and reboot. Report back.

P.s. Documentation is your friend: https://www.raspberrypi.com/documentati ... ote-access

lolalola
Posts: 9
Joined: Tue Aug 02, 2022 1:19 pm

Re: No HDMI signal - RPI 4 model B

Wed Aug 03, 2022 6:34 pm

aBUGSworstnightmare wrote:
Wed Aug 03, 2022 4:29 pm
lolalola wrote:
Wed Aug 03, 2022 3:42 pm
Okay, I also thought the adapter or cable was the problem but then I tested it with the TV and it still didn't work despite not using an adapter. I guess the HDMI cables could be bad, they both came in the RPI kit. The resolution of my monitor is 1680 x 1050.
How do I know if wrong EDID is sent by the monitor?
I haven't tried to connect via SSH because I don't know how to do that, will try as soon as I figure it out!
hmm, would start with a test first, swiching back to FKMS

Force 1680x1050 resolution by adding below to config.txt (in boot directory, you can do that on your PC/MAC as well or via SSH on the Pi.

Code: Select all

hdmi_group=2
hdmi_mode=58
search config.txt for the line 'dtoverlay=vc4-kms-v3d' and change to

Code: Select all

dtoverlay=vc4-fkms-v3d
save and reboot. Report back.

P.s. Documentation is your friend: https://www.raspberrypi.com/documentati ... ote-access
Yep, I checked config.txt and it was already changed to that. Saved and rebooted anyway but still no picture...

aBUGSworstnightmare
Posts: 5632
Joined: Tue Jun 30, 2015 1:35 pm

Re: No HDMI signal - RPI 4 model B

Thu Aug 04, 2022 4:24 am

lolalola wrote:
Wed Aug 03, 2022 6:34 pm
aBUGSworstnightmare wrote:
Wed Aug 03, 2022 4:29 pm
lolalola wrote:
Wed Aug 03, 2022 3:42 pm
Okay, I also thought the adapter or cable was the problem but then I tested it with the TV and it still didn't work despite not using an adapter. I guess the HDMI cables could be bad, they both came in the RPI kit. The resolution of my monitor is 1680 x 1050.
How do I know if wrong EDID is sent by the monitor?
I haven't tried to connect via SSH because I don't know how to do that, will try as soon as I figure it out!
hmm, would start with a test first, swiching back to FKMS

Force 1680x1050 resolution by adding below to config.txt (in boot directory, you can do that on your PC/MAC as well or via SSH on the Pi.

Code: Select all

hdmi_group=2
hdmi_mode=58
search config.txt for the line 'dtoverlay=vc4-kms-v3d' and change to

Code: Select all

dtoverlay=vc4-fkms-v3d
save and reboot. Report back.

P.s. Documentation is your friend: https://www.raspberrypi.com/documentati ... ote-access
Yep, I checked config.txt and it was already changed to that. Saved and rebooted anyway but still no picture...
you're using the HDMI output next to USB-C?

Provide a picture of your setup (Pi with cables connected). Cwn you reach the Pi via SSH?

lolalola
Posts: 9
Joined: Tue Aug 02, 2022 1:19 pm

Re: No HDMI signal - RPI 4 model B

Fri Aug 05, 2022 2:22 pm

It seems I'm not able to do the SSH thing from my old macbook unfortunately, but I did a little test by sending a picture from my phone to the Pi via bluetooth and it was successfully sent so I think the problem has to do with the HDMI output... I bought a new HDMI cable but that didn't help either. Anyway here's my setup
ImageImageImage

aBUGSworstnightmare
Posts: 5632
Joined: Tue Jun 30, 2015 1:35 pm

Re: No HDMI signal - RPI 4 model B

Fri Aug 05, 2022 2:43 pm

lolalola wrote:
Fri Aug 05, 2022 2:22 pm
It seems I'm not able to do the SSH thing from my old macbook unfortunately, but I did a little test by sending a picture from my phone to the Pi via bluetooth and it was successfully sent so I think the problem has to do with the HDMI output... I bought a new HDMI cable but that didn't help either. Anyway here's my setup
ImageImageImage
prepare a fresh uSD with Bullseye, using RPI Imager. Make sure to enable SSH (see here as well viewtopic.php?p=2016918&hilit=rpi+imager#p2016918)

Your Macbook has TERMINAL installed, so the only thing you need to know is the IP of your Pi! In TERMINAL you simply need to type (example only) 'ssh pi@192.168.178.36' with 192.168.178.36 the IP address as an example and you should be able to connect.

To get to know your IP install FING on your mobile (available for iOS and Android). Search the network and it will show you your Pi's IP :idea:

when connected via SSH run below command and post the result here:

Code: Select all

DISPLAY=:0 xrandr --verbose
This is your only posting on this topic? There is another active post where OP also has issues with an HDMI to DVI adapter.

lolalola
Posts: 9
Joined: Tue Aug 02, 2022 1:19 pm

Re: No HDMI signal - RPI 4 model B

Fri Aug 12, 2022 12:39 pm

A little update on this... I had very much trouble finding out the ip of my pi (don't own a smartphone) and eventually gave up. I bought a new raspberry pi 4 model B, it wouldn't work with the DVI monitor+adapter+hdmi cable either but it did work with the Tv. So I got a DVI to micro-HDMI cable and now the monitor and the new pi works perfectly together :) My old pi also works with the monitor and the new cable BUT the picture is tinted green and it flickers.
I guess the problem from the beginning was the adapter, and perhaps the hdmi port on my old pi has gotten worn out from having to plug the cable in and out all the time to get it to work.

andrum99
Posts: 1669
Joined: Fri Jul 20, 2012 2:41 pm

Re: No HDMI signal - RPI 4 model B

Fri Aug 12, 2022 1:00 pm

lolalola wrote:
Fri Aug 12, 2022 12:39 pm
...perhaps the hdmi port on my old pi has gotten worn out from having to plug the cable in and out all the time to get it to work.
Since there are two micro HDMI ports on the Pi 4, you can just use the other one instead if the first one is a bit dodgy 👍 That's what I do on the one Pi 4 I have which has one slightly iffy port.

lolalola
Posts: 9
Joined: Tue Aug 02, 2022 1:19 pm

Re: No HDMI signal - RPI 4 model B

Fri Aug 12, 2022 5:12 pm

andrum99 wrote:
Fri Aug 12, 2022 1:00 pm
lolalola wrote:
Fri Aug 12, 2022 12:39 pm
...perhaps the hdmi port on my old pi has gotten worn out from having to plug the cable in and out all the time to get it to work.
Since there are two micro HDMI ports on the Pi 4, you can just use the other one instead if the first one is a bit dodgy 👍 That's what I do on the one Pi 4 I have which has one slightly iffy port.
Yeah you're right.. didn't think about that. Oh well now I have two working computers :roll:

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