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HDMI display issues with TV

Posted: Sat Apr 26, 2014 1:54 pm
by soundsystem83
I received a new Raspberry Pi today as part of an OpenElec bundle. When I first connected it to my TV there was no signal through my HDMI switcher so I tried connecting directly to the TV. Still no signal, so I tried several other cables, with results ranging from no signal at all, to intermittent to consistent signal with a higher quality HDMI cable. The problem is that the display is distorted, flickering with occasional horizontal bars and all the colours are out, it's mostly green where I assume it should be black, and text is very hard to read.

I've tried formatting the SD card and installing Raspbian through NOOBs but I still have the same display problems. I've been trying various changes to the config.txt file with no luck. The only clue I have is that when I run tvservice it says there are zero modes for both CEA and DMT. Then if I try to look at the EDID, it does write some data to edid.dat but when I try to parse it it says something like bad EDID header 0 0 0 0 0 0.

Can anyone help?

Thanks

Dan

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 4:35 pm
by soundsystem83
Hmm, if I set config_hdmi_boost to 11 the colours are better, but it is still flickery, and the very left of the screen has green flickers. I've checked TP1 and TP2 and the power seems to be fine (almost exactly 5V).

Any ideas?

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 5:04 pm
by soundsystem83
Also, sometimes the display will go off for a second and then come back. Setting the hdmi boost to 11 definitely is an improvement on 10, but any higher than 11 and I get no signal at all.

I've also noticed that regardless of the settings in config.txt, the TV is always reporting the resolution as 1280x720p @ 60Hz. It is a fairly cheap Bush TV from Argos but should support full 1080p HD.

I've tried converting the edid.dat file to pheonix format and opening it in the pheonix edid editor, but it says it is invalid. The converted edid.dat is just a text file with all the EDID bytes set to zero:

EDID BYTES:
0x 00 01 02 03 04 05 06 07 08 09 0A 0B 0C 0D 0E 0F
------------------------------------------------
00 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
10 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
20 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
30 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
40 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
50 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
60 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
70 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

I'm about ready to give up. Such a shame, this is my second Pi, the first one would never get enough power (faulty polyfuse I suspect, I must have tried ten different power supplies) and now this one either won't work with my TV or possibly has a faulty HDMI output or something :(

Please let me know if anyone has any other suggestions for things I can try.

Dan

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 5:17 pm
by soundsystem83
I'm using short length HDMI cables, most don't work at all, or are intermittent, the only one I can get anything consistent with seems to be quite a high quality one... It's like the Pi is just putting out a very weak signal :(

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 5:39 pm
by DougieLawson
Try editing /boot/config.txt and adding config_hdmi_boost=4 to the bottom of it. The boost value has a range from 1 to spinal tap (11).

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 5:51 pm
by soundsystem83
I've already tried that... on 11 the colours are about right but there is still a lot of interference, and the signal sometimes drops completely. 10 is worse, anything less and it's all green. Anything higher than 11 and I get no signal at all.

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 5:55 pm
by Burngate
If config_hdmi_boost=11 gives almost-useable, I wonder if the HDMI cables aren't seating properly, either in the Pi or the TV?

Other than that, could it be the TV at fault?
- No, don't be silly, the TV is a lot more expensive than the Pi and so can't be at fault ;)

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 6:04 pm
by soundsystem83
The TV only has one hdmi input, and other devices work fine in it... it could be that the connector is not seated properly in the pi. Is there anything I can do to check/fix that?

On the other hand, the tv does not seem to be sending valid edid data to the pi. Not sure if that's the same issue as the colour and interference problems though. And setting config.txt to ignore edid and setting the hdmi group and type manually doesn't seem to help.

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 6:09 pm
by GTR2Fan
I think Burngate was suggesting that the HDMI plug at the Pi end might not be pushed all the way home. Some case designs might impede access a little in this area.

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 6:14 pm
by soundsystem83
The hdmi connector is definitely in as far as it will go at both ends. I've tried it with the case on and off as I wanted to check the test points to eliminate power supply issues.

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 6:20 pm
by GTR2Fan
Have you tried removing all other monitor related lines and just using 'hdmi_safe=1'? That would probably be a good starting point. If that works then we can tweak our way around the problem from there.

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 6:29 pm
by soundsystem83
Still green and flickery with only hdmi_safe set

Re: HDMI display issues with TV

Posted: Sat Apr 26, 2014 6:33 pm
by GTR2Fan
Hmm. I hate to say it, but this isn't looking very hopeful. I was going to use the result of that to write some custom settings for you to try, but if that doesn't give a stable picture then I don't know where to go next. Sorry.

Re: HDMI display issues with TV

Posted: Sun Apr 27, 2014 11:12 am
by Burngate
Agreed it's not looking hopeful ...
Not getting any EDID information points to the i2c channel not working, while flickering video points to a different problem with the video data channels

It would be nice to see if it had the same problem on a different TV or monitor.
Or a different Pi on the same TV ... but this is your second Pi. The first had a faulty poly-fuse? - so you never had a chance to see if it worked on your TV?

Apart from a 200-mile trip up the M1, I'm running out of ideas

Re: HDMI display issues with TV

Posted: Sun Apr 27, 2014 11:43 am
by soundsystem83
I did try it with an hdmi to dvi cable into my computer monitor but got no signal at all.

My first pi did work a bit through the tv but it kept hanging and was unstable, which I traced to the power supply issue. So maybe it is another faulty pi... seems like very bad luck to get two dud ones though... oh well

Thanks for your help anyway

Re: HDMI display issues with TV

Posted: Sun Apr 27, 2014 12:06 pm
by skullbucks.in
no need of any change in root file of os...just install noobs os and when the pi is booting up ...press 1...2...3....4....from your kwyboard ..u'll get a display output...the moment u get output means stop pressing

Re: HDMI display issues with TV

Posted: Sun Apr 27, 2014 12:18 pm
by skullbucks.in
re install your os and try again

Re: HDMI display issues with TV

Posted: Sun Apr 27, 2014 12:24 pm
by rpdom
With the DVI cable you might need to put "hdmi_force_hotplug=1" in config.txt as they sometimes don't signal that there is an hdmi connection.

Also make sure that your monitor isn't DVD-A, which is VGA in disguise. It needs to support DVI-D (or DVI-I which is DVI-A plus DVI-D).

Re: HDMI display issues with TV

Posted: Sun Apr 27, 2014 3:47 pm
by Burngate
soundsystem83 wrote:... seems like very bad luck to get two dud ones though...
Statistically, if there were a 1% failure-rate, we should expect any two random Pis to have a 1-in-10,000 chance of both being faulty.
One can prove lots of things with statistics, but from my point of view it was inevitable that I would be talking to the one person who happened to hit that 1-in-10,000, if only because none of the other 9,999 people want to talk to me.

Interesting that the first Pi worked through the TV - it does point to this Pi having faulty HDMI
Though no output at all on DVI could well be what rpdom says.

Re: HDMI display issues with TV

Posted: Mon Apr 28, 2014 2:55 pm
by SB2020
I was struggling with a very similar issue last night myself - hdmi>dvi on a Hanns monitor rescued from a skip gave very unstable image with pink and white lines all over. All the forum posts seemed to suggest poor quality cable, but I don't give up easily!

I noticed that using the same pi and cable with different SD (Noobs) and different monitor gave a perfect image so It couldn't be *just* the cables fault.

Running tvservice -d edid.dat got me a list of supported modes and suggested a preferred native mode (35), however using hdmi_mode=35 didn't work for me.
What DID work was dropping down to 1024x768 (mode18) and then using config_hdmi_boost=11 (4 gave me pink noise, 7 blue noise, 11 reduces noise to a barely noticeable level)

I had to cycle through the HDMI modes to find one that worked properly without leaving some interference (exactly as OP suggests static like interference down left hand side)

So - persevere! It may have taken 30+ reboot cycles, but I got there in the end.