Black Screen when using SDTV out

rileyav · July 13, 2022 at 3:48 PM

Hi folks really desperate for some help on this one as I have no clue.

So I got a new pi4 and installed the new stable 10.0.2? (or whatever it is). Edited the config to enable SDTV out and select a mode,

Hooked it all up and got the rainbow test screen that appears for a moment, ah sweet. Then, nothing. Just a black screen, and waiting around doesn't help either. HDMI works fine. Libreelec is running as I can SSH in no problem. Anyone know wtf the problem is?

**Da Flex** · July 13, 2022 at 9:55 PM

Read here: Click!

rileyav · July 14, 2022 at 12:37 AM

Hiya,

Thanks for the response. Unfortunately this doesn't seem to have worked although it has brought me closer. I now get to the libreelec logo boot screen, and then the screen flashes for a second and goes black. Again, still able to SSH in. I followed all the steps in the linked post

**Da Flex** · July 14, 2022 at 2:32 AM

Edit this dtoverlay line at config.txt, resulting in this:

Code

dtoverlay=vc4-kms-v3d,cma-512,composite=1

Add this line to the end of config.txt:

Code

enable_tvout=1

Add video=Composite-1:720x480@60ie to the end of your existing boot parameters line (file cmdline.txt, after the "quiet" parameter, separated by a space sign).

rileyav · July 14, 2022 at 3:08 AM

All 3 of these things were done as mentioned in the thread u linked

**Da Flex** · July 14, 2022 at 3:13 AM

Also try this alternative line (replacement for dtoverlay=vc4-kms-v3d,cma-512,composite=1) :

Code

dtoverlay=vc4-kms-v3d-pi4,composite

rileyav · July 14, 2022 at 3:23 AM

Still no luck unfortunately. this line:

dtoverlay=vc4-kms-v3d-pi4,composite

Was put in the distroconfig.txt is this correct? Or do I need to add it to the actual config.txt

**Da Flex** · July 14, 2022 at 3:28 AM

Into actual config.txt please. As you know, always reboot after an edit.

rileyav · July 14, 2022 at 3:49 AM

Yeah still no luck. Tried the original line and also the alternative one in config.txt, still just flickers once and then goes black after the libreelec boot screen

**Da Flex** · July 14, 2022 at 3:59 AM

You could remove the interlaced parameter "i" from the cmdline.txt line.

PS: Check the wiring of linked thread.

PPS: Downgrading to LE 10.0.1 is also worth a try, because thats the version of the linked thread.

rileyav · July 14, 2022 at 1:41 PM

Tried that and no luck. I'll give the downgrade a go, could you point me towards where I can get the 10.0.1 file please?

EDIT: ah! working on the 10.0.1 version! Only issue is that the gamma seems really unusually high, everything looks real washed out when compared to running it into the same tv with a HDMI>composite converter. Any idea what that may be?

**Da Flex** · July 14, 2022 at 5:58 PM

To my knowledge there is no gamma correction by software (for both, composite and HDMI). I would use hardware to fix this: Use an adjustable resistor on the composite video pin.

rileyav · July 14, 2022 at 6:00 PM

On the composite video pin? Could you elaborate a little please hehe. I'm using the 3.5mm jack

**Da Flex** · July 14, 2022 at 6:08 PM

According to this diagram, the video contact is the yellow plug. You can solder an adjustable resistor into your existing cable (inner contact of the yellow plug).

rileyav · July 14, 2022 at 6:13 PM

Ah, as much as I appreciate the pointers there hardware modification is truly a last resort for me on this one..

Luckily I have the solution! Install the libreelec 10 nightly, follow the instructions in the thread you linked and it works perfect. Not a clue what the cause was but I am a happy bunny now. Thanks for your assistance

**Da Flex** · July 14, 2022 at 6:15 PM

Congrats!

rileyav · July 14, 2022 at 6:25 PM

Thanks haha although I think it has more to do with whoever has fixed the issue I was having with the nightly update. While I'm here I don't suppose you could tell me how to access the home folder (specifically home/pi/) via SSH? The filesystem is different in LE and I'm not at all up on linux anyway so I'm rather lost on what the actual path is

**Da Flex** · July 14, 2022 at 6:29 PM

LE only uses one user, which is "root". So after SSH login you are on root's home folder, and no other home folders exist.

Black Screen when using SDTV out

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