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Investigating the HDMI "Green Screen After a Few Seconds" Problem

Black Hole said:
Don't get me started on EDID! My electriQ (sic) UHD monitor returns a manufacturer ID which is identified in the tables as "do not use". That means when I go into desktop settings, the desktop layout mapping to monitor(s) disconcertingly displays "do not use" as my main (only) monitor! Very confusing.

I cured it by editing the look-up table, but that means doing it again every time the OS gets updated.
Click to expand...
I wonder if it's worth trying your troublesome HDR (and a working HDR) with this monitor? It may produce useful data points. If it green screens then the issue is most likely with the Humax. If it doesn't produce green screen then it may be to do with HDCP revocation list (assuming the monitor isn't linked to the internet). Although the EDID issue may throw this guess out.

I can't decide if my green screen HDR is an issue with hardware or software/firmware.
If it is hardware - it doesn't explain the ability to show the screen properly during pre-HDCP (as BH mentioned).
If it is software/firmware, then the only thing I can think of is the HDCP revocation list was tripped - making the HDR incompatible with my TV.

From these links some TV makes had issues with the HDR - LG, Samsung, Sony and occasionally Panasonic, Sharp.
(Jan 2012) https://community.sony.co.uk/t5/oth...ng-humax-hdr-via-hdmi-to-sony-kdl/td-p/282489
(Apr 2013) https://myhumax.org/forum/topic/green-screen-issue
(Apr 2014) https://myhumax.org/forum/topic/green-screen-1
(Oct 2015) https://myhumax.org/forum/topic/green-screen-saga#post-41394
(Oct 2016) https://myhumax.org/forum/topic/green-screen-2
(Mar 2018) https://myhumax.org/forum/topic/green-screen-3

In my case my first HDR purchase was June 2016. This developed an intermittent green screen issue. The green screen issue gradually got worse and became permanent in roughly 2018. I haven't had TV firmware updates since 2013, only CFW updates (but others have had the issue without CFW - so it can't be that).
My one developed issue like this one
BMAX said:
I convinced myself that it was a timing issue caused by component ageing as, in my case the problem first showed up some years ago with a Sony Bravia TV, and got progressively worse over some months. When the Bravia was replaced by a Panasonic, the green screen went away. However, some years later, the problem has resurfaced very occasionally. It remains to be seen whether it gets gradually worse as before.
For info the Loader is 7.31. I didn't try changing it as others had reported no improvement.
Click to expand...
It's so confusing.
 
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Maybe ageing, or dust? The HDMI article I linked above explains that there is a capacitance limit outside which the I2C/DDC data exchanges that set up the link may be corrupted (PCB I2C: 400pF, DDC: 700pF). While a single domestic link wouldn't exceed that limit, might not ageing or faults and muck around the PCB traces and HDMI connectors have that effect?
 
/df said:
Maybe ageing, or dust? The HDMI article I linked above explains that there is a capacitance limit outside which the I2C/DDC data exchanges that set up the link may be corrupted (PCB I2C: 400pF, DDC: 700pF). While a single domestic link wouldn't exceed that limit, might not ageing or faults and muck around the PCB traces and HDMI connectors have that effect?
Click to expand...
I discounted faulty cable and/or TV socket issue because I changed cables(1m/2m) and TV HDMI sockets.
So HDR1(with green screen issue) doesn't work with the TV regardless of the cable or HDMI TV socket in use.
My other HDR works fine on any TV HDMI socket and cable combination.

So that leads me to think the issue may be with one STB - HDR1(with green screen issue).
eg hardware or software. Also remember this HDR1 works fine using HDMI output during the loader boot screen eg for firmware updates.

Or the issue is with the pairing of HDR1 with my particular TV.
Other people work around the issue by changing the TV or HDR.

I don't think the TV is at fault (or unlikely) because it works with other HDMI (STB/PC) devices, including another HDR.
 
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Saw this on eBay
www.ebay.co.uk

Humax HD-Fox T2 HD DVB-T2 Freeview TV Digital Receiver ** SEE NOTES ** | eBay

Other operations like EPG and channel changing are fine using the buttons on the box.
www.ebay.co.uk
It's a HD FOX T2 that has certain issues, including "Doesn't work with some LG TVs (displays a green screen on my model)"

Edit1: This is the full description of the item -

"Although this is fully-working in my setup (see pictures of it working) note the following important issues and information I found in my experience with it which may cause it not to work - please read before deciding to buy:
  • No remote control - I used the "HDMI Link" feature of my TV to remote control it and tune it - pre-tuned to West Midlands (Sutton Coldfield transmitter).
  • I tried a couple of unofficial replacement IR remote controls for it I bought on ebay, but these didn't work, so I'm not sure if it needs a real official remote control by the manufacturer, or if the IR sensor has an issue.
  • Without a remote control or HDMI control, tuning is only possible with a "System Flush Update File" on a reset USB key from HummyTV website as access to the reset/installation option requires entering 0000 as a code via remote control otherwise. Other operations like EPG and channel changing are fine using the buttons on the box.
  • Doesn't work with some LG TVs (displays a green screen on my model) - had used this fine with a HDMI Capture USB device for a computer with pass-through and that worked OK and could enable the HDMI Link and tuning.
  • Comes pre-installed with custom firmware from HummyTV website (see the wiki guide there - requires a USB stick to enable all features)
Will be posted same or next working day."
 
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Interesting. Might be worth picking up, but I have enough HD-FOXes. I've never tried ARC, and I don't think it has been discussed much on the forum (except a recommendation not to turn it on!).
 
My Sony Android TV has this problem now. All has been stable for years, but the green screen issue at Humax FOXT2 boot has been getting more frequent to the point now that it is every time. After the green screen is I reboot the Sony Android TV all is OK, i.e. the Humax HDMI picture is fine....... and the family are happy....

I am about to try a different HDMI socket on the TV to see if that makes any difference.

Has an hardware fault feel to me but........
 
Still having issues. It's not the HDMI cable or the TV HDMI port. Even put the Humax in safe mode and the green screen appears at the first boot of the day. Unplugging the HDMI cable and re-inserting fixes the problem and all is good. Rebooting the box and TV afterwards does not result in a green screen. The Humax has to be off for a while e.g. over night for the green screen on first boot to occur.
 
Fraser Cavanagh said:
Still having issues. It's not the HDMI cable or the TV HDMI port. Even put the Humax in safe mode and the green screen appears at the first boot of the day. Unplugging the HDMI cable and re-inserting fixes the problem and all is good. Rebooting the box and TV afterwards does not result in a green screen. The Humax has to be off for a while e.g. over night for the green screen on first boot to occur.
Click to expand...
In which case leave the Humax on 24x7 - even with energy price rises the extra electricity usage probably won't break the bank

Or schedule a repeating reminder for before your normal use time to warm up the box,
 
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The same Toshiba TV + HDR Fox T2 combo that I reported as occasionally throwing up incorrect colours is now, almost always, producing a green screen. The a7.33 boot screen appears (maybe flashes green before it appears?), then program content flashes on for ~0.5s before dropping to green screen. No HDCP message is seen on the analogue output. Cables (etc) haven't been changed.
 
/df said:
The same Toshiba TV + HDR Fox T2 combo that I reported as occasionally throwing up incorrect colours is now, almost always, producing a green screen. The a7.33 boot screen appears (maybe flashes green before it appears?), then program content flashes on for ~0.5s before dropping to green screen. No HDCP message is seen on the analogue output. Cables (etc) haven't been changed.
Click to expand...
If I had this problem I'd be have a look at the voltage levels of the HDMI signals. It has the feel of something to do with the local SMPSU for the HDMI i/f if there is one, possibly the output cap losing value as seems to be happening elsewhere on the board.
 
Pretty much my suspicion, but it's all part of a stack of media boxes and debugging will have to wait for the stack to be disassembled. Maybe my dump Denon AV receiver will turn out to be functional when commissioned and solve the HDMI issue as well.
 
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