Rpi4: no video output

[alexxx]

I bought a Rpi4 to upgrade my Rpi2b that runs Kodi connected to my projector (Optoma hd142x), but after installing LibreElec, I saw no output at all on the projector.
Without SD card in, it does the correct LED blinking pattern, so the hardware seems to boot ok.
I tested both HDMI outputs on the Rpi4, without success.
I tried switching on the monitor both before and after the Rpi4 boot - no effect.
I set hdmi_force_hotplug=1 in config.txt, again nothing.
I connected an old LCD portable display and an old 14'' monitor, both of which always succesfully worked on previous Rpi models, and again I have no HDMI.
All the hardware was bought at an official store, and the power supply is the correct one for the Rpi4.
One detail, I dont know if it's important: given the choice between an HDMImicro-to-HDMI cable or adapter, I choose the adapter - there are perhaps issues with those?

[B.Goode]

given the choice between an HDMImicro-to-HDMI cable or adapter, I choose the adapter - there are perhaps issues with those?

There should not be a generic issue with that choice. But maybe the specific adapter you have bought is faulty? Or is not fully inserted into the hdmi0 socket?


You don't mention trying to boot your new hardware from a newly created microSD card containing a current version of the Raspbian Buster Operating System. A card containing a Raspbian Operating System from prior to the release of the RPi4 in mid 2019 might not be compatible.

[alexxx]

Thank you for your reply!
The adapter if fully inserted, I rechecked it multiple times...
The microSD was bought with the Rpi4, it is 15GB and I copied libreElec on it by the dd command, with the usual precautions (unmount it, use bs=1m and conv=sync, unmount it again before extracting it...).
I also tested the latest Raspbian as you suggested, but the behaviour is the same: no output, with the red LED constantly on while the green LED blinked showing that the Rpi4 was apparently booting.

[FTrevorGowen]

...
I also tested the latest Raspbian as you suggested, but the behaviour is the same: no output, with the red LED constantly on while the green LED blinked showing that the Rpi4 was apparently booting.

Are you able to enable / have you enabled SSH for Raspbian via the "dummy" ssh file method (option 3 here: https://www.raspberrypi.org/documentati ... /README.md ) ? If so, can you remotely login via SSH (perhaps via your, hopefully still working, P2B) and post the output of these tvservice commands which may give us a further clue or two:

Code: Select all

tvservice -n
tvservice -m DMT
tvservice -m CEA
tvservice -s

Trev.

[mahjongg]

did you use the correct HDMI port, the left one?

[alexxx]

did you use the correct HDMI port, the left one?

yes - though I tested the other too just to be sure...

[jamesh]

did you use the correct HDMI port, the left one?

Although port 0 has slightly better performance (4kp60), both should work out of the box.

[alexxx]

Are you able to enable / have you enabled SSH for Raspbian via the "dummy" ssh file method (option 3 here: https://www.raspberrypi.org/documentati ... /README.md ) ? If so, can you remotely login via SSH (perhaps via your, hopefully still working, P2B) and post the output of these tvservice commands which may give us a further clue or two:

Code: Select all

tvservice -n
tvservice -m DMT
tvservice -m CEA
tvservice -s

Trev.

I'll try it immediately, I'm just not sure how to also enable wifi to my local network, if I'm not yet able to access it... do you think that this instructions work on the Rpi4 ? https://desertbot.io/blog/headless-rasp ... wifi-setup

[B.Goode]

Are you able to enable / have you enabled SSH for Raspbian via the "dummy" ssh file method (option 3 here: https://www.raspberrypi.org/documentati ... /README.md ) ? If so, can you remotely login via SSH (perhaps via your, hopefully still working, P2B) and post the output of these tvservice commands which may give us a further clue or two:

Code: Select all

tvservice -n
tvservice -m DMT
tvservice -m CEA
tvservice -s

Trev.

I'll try it immediately, I'm just not sure how to also enable wifi to my local network, if I'm not yet able to access it... do you think that this instructions work on the Rpi4 ? https://desertbot.io/blog/headless-rasp ... wifi-setup

That third-party information might work, but why not simply use the documentation provided by Raspberry Pi themselves -
https://www.raspberrypi.org/documentati ... eadless.md

[alexxx]

Are you able to enable / have you enabled SSH for Raspbian via the "dummy" ssh file method (option 3 here: https://www.raspberrypi.org/documentati ... /README.md ) ? If so, can you remotely login via SSH (perhaps via your, hopefully still working, P2B) and post the output of these tvservice commands which may give us a further clue or two:

Code: Select all

tvservice -n
tvservice -m DMT
tvservice -m CEA
tvservice -s

Trev.

So, these are the not-so-good-looking results:

Code: Select all

pi@raspberrypi:~ $ tvservice -n
[E] No device present
pi@raspberrypi:~ $ tvservice -m DMT
Group DMT has 0 modes:
pi@raspberrypi:~ $ tvservice -m CEA
Group CEA has 0 modes:
pi@raspberrypi:~ $ tvservice -s
state 0x120001 [TV is off]

[StuartF]

Could it be the HDMI cable?
I had the same problem using an adaptor and existing cables I had used for PI1,2 & 3.
These were HDMI spec 1.0 and spec 1.3.
I got a HDMI 2.0, which is 4K compatible, and the problem was resolved.

[FTrevorGowen]

Are you able to enable / have you enabled SSH for Raspbian via the "dummy" ssh file method (option 3 here: https://www.raspberrypi.org/documentati ... /README.md ) ? If so, can you remotely login via SSH (perhaps via your, hopefully still working, P2B) and post the output of these tvservice commands which may give us a further clue or two:

Code: Select all

tvservice -n
tvservice -m DMT
tvservice -m CEA
tvservice -s

Trev.

So, these are the not-so-good-looking results:

Code: Select all

pi@raspberrypi:~ $ tvservice -n
[E] No device present
pi@raspberrypi:~ $ tvservice -m DMT
Group DMT has 0 modes:
pi@raspberrypi:~ $ tvservice -m CEA
Group CEA has 0 modes:
pi@raspberrypi:~ $ tvservice -s
state 0x120001 [TV is off]

So, assuming that Pi (the P4) was physically connected to a TV, yes that's not good - so now we need to determine which "bit" is the problem (Pi, HDMI cable etc., TV). This entails swapping out, if you can, one part at a time. IIRC, you're using a micro-to-full-size HDMI adaptor so, remove that and replace the P4 with your P2B (try with the uSDHC card you normally use in it first and then with the card from the P4B - if the adaptor and/or the P4B's uHDMI connector giving problems then I'd expect one of the cards to boot and display something since a uHDMI connection is no longer in use). If the P2B boots at all please SSH in and run those tvservice commands again and report back any differences. Do you have any manual or model type etc. for the T.V. that either states (or can be googled) what HDMI modes the T.V. supports? This sort of "fault-finding" can be a slow and frustrating process but, hopefully, will be sorted out in the end.
Trev.

[alexxx]

Are you able to enable / have you enabled SSH for Raspbian via the "dummy" ssh file method (option 3 here: https://www.raspberrypi.org/documentati ... /README.md ) ? If so, can you remotely login via SSH (perhaps via your, hopefully still working, P2B) and post the output of these tvservice commands which may give us a further clue or two:

Code: Select all

tvservice -n
tvservice -m DMT
tvservice -m CEA
tvservice -s

Trev.

So, these are the not-so-good-looking results:

Code: Select all

pi@raspberrypi:~ $ tvservice -n
[E] No device present
pi@raspberrypi:~ $ tvservice -m DMT
Group DMT has 0 modes:
pi@raspberrypi:~ $ tvservice -m CEA
Group CEA has 0 modes:
pi@raspberrypi:~ $ tvservice -s
state 0x120001 [TV is off]

So, assuming that Pi (the P4) was physically connected to a TV, yes that's not good - so now we need to determine which "bit" is the problem (Pi, HDMI cable etc., TV). This entails swapping out, if you can, one part at a time. IIRC, you're using a micro-to-full-size HDMI adaptor so, remove that and replace the P4 with your P2B (try with the uSDHC card you normally use in it first and then with the card from the P4B - if the adaptor and/or the P4B's uHDMI connector giving problems then I'd expect one of the cards to boot and display something since a uHDMI connection is no longer in use). If the P2B boots at all please SSH in and run those tvservice commands again and report back any differences. Do you have any manual or model type etc. for the T.V. that either states (or can be googled) what HDMI modes the T.V. supports? This sort of "fault-finding" can be a slow and frustrating process but, hopefully, will be sorted out in the end.
Trev.

I thank all of you for the help you gave me...
The problem, it turns out, was with the adapter: changing it with a microHDMI-HDMI cable solved the problem immediately.

Thank you again!

Alessandro