x414
Posts: 3
Joined: Fri Mar 29, 2013 2:52 pm

Always losing HDMI signal..

Fri Mar 29, 2013 2:57 pm

Hey guys I'm constantly losing HDMI signal and this is going to drive me crazy. I've searched before posting of course. I've tried almost every setting possible I guess.. And tservice is not even runing...
I've tried different values for config_hdmi_boost, up to 20 but it doesn't change anything. After 1 min or 2 I lose the signal and can't take it back. I also tried hdmi_safe=1, #hdmi_drive=2 played a bit with the hdmi_group and _mode even if tservice doesn't run.
Any idea about this?

Thank you

McNeil
Posts: 22
Joined: Sat Mar 23, 2013 10:30 am

Re: Always losing HDMI signal..

Fri Mar 29, 2013 3:42 pm

Make sure your RPi is not crashing, resulting in a black screen and loss of hdmi signal.

- Try with another HDMI cable.

- Could also be caused by a faulty/unstable USB Power supply.

- Try to add these lines in your config.txt

Code: Select all

avoid_safe_mode=1
hdmi_pixel_encoding=3
hdmi_drive=2
hdmi_force_hotplug=1

x414
Posts: 3
Joined: Fri Mar 29, 2013 2:52 pm

Re: Always losing HDMI signal..

Fri Mar 29, 2013 4:44 pm

Thanks for your reply.
I don't have another hdmi cable atm so I can't try but I use this cable si I know it's working.
I've tried to add these options but no change. I'm sure it's not crashing because I can ssh to it. And for the power it's a 5v charger from my samsung phone. I don't have the tools to measure the power atm :/

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johnbeetem
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Re: Always losing HDMI signal..

Fri Mar 29, 2013 8:33 pm

x414 wrote:Thanks for your reply.
I don't have another hdmi cable atm so I can't try but I use this cable si I know it's working.
I've tried to add these options but no change. I'm sure it's not crashing because I can ssh to it. And for the power it's a 5v charger from my samsung phone. I don't have the tools to measure the power atm :/
I vote for iffy power. When I was first running my RasPi, I had an iffy power source. RasPi worked fine at 4.65V (TP1-TP2) but below that I'd first get green snow on the screen and then it would blank out completely. Lots of fun -- ran great until I did a compile, and then the extra power required by the CPU would dip the voltage enough to get the green snow, which would go away when the compile was done. Actually, a nice "feature" in a way :-)

You might try a different Micro USB power cable. Some of those have very thin conductors which produce a significant voltage drop even though the power supply itself is fine. The shorter the better.

TheQuestor
Posts: 80
Joined: Wed Nov 28, 2012 9:15 am

Re: Always losing HDMI signal..

Fri Mar 29, 2013 8:39 pm

I also would agree that it is probably an iffy wall wart. Phone chargers aren't exactly the most stable units out there. Also the usb cable is even more iffy. I have several that work GREAT and some that do not. And cost != quality with these things, some of my cheaper ones work better than some of my more expensive ones.

x414
Posts: 3
Joined: Fri Mar 29, 2013 2:52 pm

Re: Always losing HDMI signal..

Mon Apr 22, 2013 4:48 pm

Hey guys I'm digging my old thread but I finally got a new charger. http://www.amazon.fr/Chargeur-Alimentat ... spberry+pi this one that looks to works fine for everyone else.
But for me it's still the same.. Though I need like 10 minutes before I loose the hdmi signal, then it doesn't take it back and the only option is to reboot : (

Pinonymous
Posts: 2
Joined: Sat Mar 14, 2015 3:02 pm

Re: Always losing HDMI signal..

Sat Mar 14, 2015 3:45 pm

Hi.
I am pretty new to Raspberry Pi and Raspbian and Linux. However i recently bought my self one RaspberryPi 2B and hook it up and set it up and it works perfect but i have that problem where randomly the screen on TV and audio that is going through the HDMI cable stop for few secs and comes back again. It does not seems that the Computer is freezing at all but it looks like it loses signal for a moment and comes back again.

I have noticed this because when the "blackout" occurs the music stops also, but when is coming back from the "blackout" music does not continue from where it stops but it continues from where it should be(like it does not stops in the background). However this also occurred to me with my PC and Windows and the same cable(i use this one because is longer is 3m cable so it reaches from my Desk to TV) but on windows was more random for me because it happens in the middle of the movie or something and most of the time the cooling fan was louder due to probably some processes in the background.

Raspberry is nearly same it happened to me while zooming in and out in web browser.
I had 200mA power supply in the beginning but i just changed it to 2 Amps power supply for External HDD and it does not looks like it has any difference it even looks like it happens more. I have it working with 2 Amps power supply for just one day or couple of hours and today i turned it on and it happens again and i am sure that it will happen tomorrow. And it also looks like it is only happening in the beginning after booting the Raspbian, and it looks like it stops after some time.

I will try to switch cable but almost everybody that had this problem and switch cable did not solve the problem.

This is the link of youtube video that shows the problem but the audio and video are comming back faster than this:
https://www(DOT)youtube(DOT)com/watch?v=ls0krJjblYQ
So if anybody have a recipe solution for this and know what is the problem, I would be appreciating their time to post a reply.

Thx to everybody's time for reading this.

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mahjongg
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Re: Always losing HDMI signal..

Sat Mar 14, 2015 7:47 pm

the problem is probably caused by a HDMI cable with too much attenuation, so that the HDMI signals arriving at the TV are too weak. For that the config.txt setting "CONFIG_HDMI_BOOST=" can be used to increase the drive level.
try:

CONFIG_HDMI_BOOST=4

don forget to remove the comment code "#" before the line, or the line will be commented out.

also read the config.txt documentation in the help section:
http://www.raspberrypi.org/documentatio ... fig-txt.md

post edit, small correction, use CONFIG_HDMI_BOOST not HDMI_DRIVE

Pinonymous
Posts: 2
Joined: Sat Mar 14, 2015 3:02 pm

Re: Always losing HDMI signal..

Sun Mar 15, 2015 6:38 pm

thx just tried. we will see if it happens in future.

vletroye
Posts: 2
Joined: Sat Aug 08, 2015 10:42 pm

Re: Always losing HDMI signal..

Sat Aug 08, 2015 10:48 pm

Hi x414

I have the same (or at least a very similar) issue as you.
I set "CONFIG_HDMI_BOOST=4" in my config.txt file but without success...
My projector still loses the HDMI signal from time to time (~3 to 4 times during a movie) :(

And you ? Did you solve your issue ?
Thx in adv for your feedback!

V.

Jabulon
Posts: 19
Joined: Sun Jan 14, 2018 10:45 am

Re: Always losing HDMI signal..

Sun Jul 22, 2018 5:36 pm

Anyone got a solution for this? I have the same issue as reported further up. I loose sig for a second or so and it comes back but the video track was still playing in the background

vletroye
Posts: 2
Joined: Sat Aug 08, 2015 10:42 pm

Re: Always losing HDMI signal..

Sun Aug 05, 2018 7:59 pm

I had this problem such a long time ago that I can't remember what solved my problem preciselly.
But I know I did changed the power adapter and the HDMI cable + reinstalled my OS (RasPlex).

V.

asuareza
Posts: 1
Joined: Tue Mar 10, 2020 1:47 am

Re: Always losing HDMI signal..

Tue Mar 10, 2020 2:01 am

I just bought a Raspberry Pi 4b and have been facing this problem consistently.

It is just the signal to the TV that loses connection. If I check the signal through a VNC connection, everything else (including the image) keeps working.

I tried everything mentioned here except the hardware changes (power supply).

What fixed it for me was going into the raspberry configuration, and disable the "Screen Blanking" option.

Regards,

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