Odroid N2 - HDMI Stopped Working

my N2 purchased in Sept 2019 suddenly decided to stop sending a signal out on HDMI, without obvious cause. ONe day it worked, the next it didn’t and I don’t remember changing anything with the N2, the TV or the cables.
I’ve tried rebooting, changing display and
What Does Work

  • The N2 boots and runs successully. SSH and VNC access still work
  • CEC turns the TV on when the N2 boots
  • The N2 seems to read the EDID successfully and accurately
  • The TV recognises the name of the connected N2 and displays it on the otherwise blank screen
  • Initially played videos would appear on VNC screen but even that has stopped now (probably due to me playing with settings)

What Doesn’t Work

  • No display on the screen ie. TV screen is black other than TV generated input info
  • No sound. This includes videos, recorded tv and music plus Coreelec navigation sounds

I’ve tried

  • Moving cables, different cables, different ports on the TV and attaching a different device to the same TV ports. There’s no evidence of a TV problem
  • Changing Display and Audio settings in Coreelec
  • Downgrading to 9.2.1 and Upgrading to nightlies (20200430)

I’m seeing a lot of these errors in DMESG, which look suspicious to my untrained eye

[ 1307.031268@0] hdmitx: err chn setting, must be 2, 4, 6 or 8, Rst as def
[ 1307.031270@0] hdmitx: err chn msk, must larger than 0

Here’s a paste of logs and config http://ix.io/2kx8

Help. This is driving me crazy :sweat_smile:

Do you see the boot logos at all?

nope … nothing :frowning:

Seems like the death symptoms like my N2 failure.
https://forum.odroid.com/viewtopic.php?f=181&t=35998&p=267295#p264622

yes, you may be right.
I found this link yesterday HDMI Hardware Test - OhmMeter
My test suggested there “may” be a hardware error (~1-5kOhm resistance with my dodgy meter)… but that seems odd if the edid is read and the CEC signal is transmitted ok … why would some pins work and not others - without some kind of mechanical or heat stress (and there’s been none)
frustrating

If yours has failed what are you doing with it now ? Any use as a server ? I suppose I could use it as jump box or container host but setup might be challenging without a screen - just have to hope ssh works out of the box

I returned it in Good Faith that my term of use was so ridiculously short that Hardkernel may honour a return or at least a partial discount for a new one.

Unfortunately that is not the Hardkernel business model.

Read HERE

How to use AV / CVBS Video Output You do need an AV composite cable and it works surprisingly well

thanks - I had completely overlooked the CVBS output.
Not great for a media player attached to a 1080P TV … but at least it provides some kind of window into what’s happening :slight_smile:

In the meantime I’ve restored the trusty old Mini M8s+ … the most reliable player I currently own. I think I’ll go back to the “cheap” chinese units - I’ve found them to be more reliable generally.

1 Like

EDID & CEC have seperate signals with different circuit design, therefore still working.
https://forum.odroid.com/download/file.php?id=10240
The components you measured on the LVDS lines are Common-Mode filters with builtin ESD protection. If resistance from signal to GND is only kOhms, there was likely an ESD incident. The good thing is that you can replace them (or bypass, although not the best idea…) more easily than the CPU (if HDMI port not also damaged by that incident).

I believe they made a new revision N2 to combat these issues but it does sound like the N2 death issue if you do not even see the boot logos, I believe there is a guide on their forum for fixing them but it requires soldering and changing some component.

For the fix, are you talking about the resistor change to increase the LVDS voltage swing?
You have some details of new N2 pcb rev? Is this ODROID-N2plus - pcb rev. 2019-11-20)?

IMO they have to refine their ESD strategy. The main issue is likely that they use CM filters with TVS on both ends. The one to connector side is fully exposed to the transient, and maybe too weak, so just fails after first shot, while the other one is quite useless.
Would be state-of-art to use a dedicated device with stronger TVS only on one side (e.g. this or this, designed even for HDMI2.0)

I’m seeing to many reports of this hdmi issue,there was a guy last week on freektab.com with the same problem,I’d be really pissed off if this happened to me as these boxes are not cheap,cost me £124 so to hear these boxes failing within such a short time is worrying,7 bought mine from odroid uk Thinking I’d be OK cause anything electrical must have atleast 1y warranty,by law it’s a actually 5y warranty in the uk but trying to get them to honour that is another story,but they usually honour a 1y,but odroid uk seem to be pulling a fast one with a 4 week warranty which totally illegal

thanks for the comments and suggestions
not sounding good really is it
I’m not really brave enough to take a soldering iron to somethinng like this … for all sorts of reasons :slight_smile:
looks like I now have an ARM mini-server. Maybe. If I can make Arch or Ubuntu work ie. if the build has SSH support out of the box

Pretty disappointing to be on the wrong end of such a quality issue :frowning:
It has encouraged me to make Kodi work from an LXC container on my J4015 box (USB IR passthrough had me foxed for a while) … so am using that for the moment and holding the Mini M8S+ in reserve - it has been rock solid ever since I first received it in 2016 (?), shame they don’t make them any more

One last question regarding the N2 failure:
Did you see the 1-5kOhms on all of the LVDS lines, or only on one of them (or only on L8 or L9)?
It would be really interesting to find out if it’s the SOC or the ESD protection failing, as you wrote you didn’t change any cabling…

I have a mixed relationship with my multimeter :slight_smile:
Just placed on probe on L9 and the rightmost line into the HDMI connector - which showed ~1k Ohm based on diagram here Hardkernel - No HDMI After Using Adapter and here Hardkernel - N2 Received & No HDMI Output
What should I test for more insight ?

Please measure each signal line separately against GND:
Blue marked contacts are all the same GND signal, so doesn’t matter which one you use.
Blue vs L8.1, Blue vs L8.2…
Blue vs L9.1, Blue vs L9.2…
grafik

Not sure I believe my own data (poor eyesight and dodgy meter). Ground used was the body of the Ethernet adapter housing (I stuck the probe to it with tape and verified measurement was largely unchanged from manual against #9). Here it is
L8 01 5k
L8 02 4k
L8 03 4k
L8 04 3k

L9 01 15k
L9 02 15k
L9 03 13k
L9 04 13k

Index numbers are counted from left as per the diagram you posted. The numbers all seem way too low
Does this seem reasonable to you, given that CEC works ?