New TV Provokes Green Screen Issue

JefUK

New Member
I have a Humax HDR Fox T2 which has performed very well for 10+ years. When feeding into a new Panasonic TV the HDMI handshake fails and produces the dreaded “green screen”. On the old TV, also a Panasonic, there was very occasionally a very short green-screen flash but it then connects and works perfectly.

I have tried replacing the T2 with an Aura but get intermittent but very severe pixelation on the SFN of COM7. I have had the problem with two copies of the Aura. The T2 never showed this problem, or does four other TV’s fed from the same aerial system at the same time. Because the Aura is not fit for purpose, at least my purpose, I have had to buy a Manhattan T3-R. The Manhattan does exactly what it is designed to do and does it well - but unfortunately I prefer the T2.

Looking at the T2 PCB the HDMI transmission interface is done by two quad flat package IC’s (DA9984A/15/13 and DA19977A/15C129). The DA19977A is an HDI receiver with HDCP, while the DA9984A is the receiver.

Presumably the problem lies with these chips or the associated clock generators. The data sheet for the DA19977A refers to software drivers and so presumably these later versions of the Humax software has incorporated these.

Does any reader know if anyone has had the “green-screen” issue fixed by a hardware repair, such as the replacement of these chips? Alternatively are replacement main boards available from Humax?
 

Black Hole

May contain traces of nut
Does any reader know if anyone has had the “green-screen” issue fixed by a hardware repair, such as the replacement of these chips?
Not that we've ever heard of. Cost of repair exceeds value.

Alternatively are replacement main boards available from Humax?
Definitely not.

The data sheet for the DA19977A refers to software drivers and so presumably these later versions of the Humax software has incorporated these.
Later versions? All versions would have to drive these chips!

Don't be so quick to blame these chips for the green screen thing. The HDD start-up problem (or at the very least some instances of it) has been traced to a particular capacitor going dry, but it was not obvious and the causal chain remains unclear. There are similar capacitors all over the board, so marginal problems could pop up anywhere and the green screen might be another symptom.

If you plan to investigate and report, I recommend you start a new thread. The investigation into the HDD supply is here: https://hummy.tv/forum/threads/start-up-fails-when-hdd-connected.10164/; you can search "green screen" for existing green screen threads.
 
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MartinLiddle

Super Moderator
Staff member
I have tried replacing the T2 with an Aura but get intermittent but very severe pixelation on the SFN of COM7. I have had the problem with two copies of the Aura.
As a matter of interest, did you buy the Aura as new or refurbished? I can't comment on COM7 reception because I receive from a local transmitter that doesn't carry COM7.

I have a vague recollection that someone reported fixing the green screen issue with a new TV by changing a setting on the TV; I think it might have been the HDMI version.
 

BMAX

Member
Don't be so quick to blame these chips for the green screen thing. The HDD start-up problem (or at the very least some instances of it) has been traced to a particular capacitor going dry, but it was not obvious and the causal chain remains unclear. There are similar capacitors all over the board, so marginal problems could pop up anywhere and the green screen might be another symptom.
Agreed. In my case (and some others), the problem became slowly worse over a period of years. This is not typical for digital components, which tend to either work or not. Again, my problem went away following a TV change, but has recently started giving short bursts of green screen when starting up. A second T2 has always given a short burst of green, but has got no worse over the years.
 

MartinLiddle

Super Moderator
Staff member
The HDD start-up problem (or at the very least some instances of it) has been traced to a particular capacitor going dry, but it was not obvious and the causal chain remains unclear. There are similar capacitors all over the board, so marginal problems could pop up anywhere and the green screen might be another symptom.
I agree it might be another capacitor related issue where it has worked perfectly for a long time and then gradually deteriorated but there is a class of green screen problems that affected brand new HDR-FOX T2 and TVs.
 
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BMAX

Member
It could still be the same mechanism if something is marginal to start with.. For example 99% production work OK, but with say 10% drift, about 10% fail.
 
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Black Hole

May contain traces of nut
I'm with ML on that one. Clearly we have no new HDR-FOXes to contend with, but plenty of TVs with newer revision HDMI/HDCP specs. Regardless, this thread is clearly about failures which cannot be attributed elsewhere: if a fault is coincident with a change in the overall environment, the first thought should not be that the HDR-FOX has failed.
 

RichFX

New Member
When feeding into a new Panasonic TV the HDMI handshake fails and produces the dreaded “green screen”.
Hmm, an off-the-wall obvious thought, I assume you have tried a few nice, clean, shiny new HDMI leads? And blown the fluff out of the sockets?

The year before lockdown I was asked to look at a brand-new audio extractor box that refused to pass the HDMI from the CD/Blu-ray (no analogue output) on to the owner's TV, black or green screen being among the symptoms.
We tried six different known working (without the box in the way) HDMI leads, but no two worked via the box.
The box did extract the audio with one lead, the one that was tight as tight can be, and that gave the green screen with some of the others on the output side.
Careful examination of both in and out HDMI connectors in the box revealed a lack of gold and quite a lot of tarnish. We probably used its lifetime count of insertions that afternoon!
Our conclusion was that either the box was unable to pass the HDCP handshake, or the HDMI connectors were useless, or even both. It was binned, being too cheap to bother with returning to Az, and an spdif to analogue converter bought instead.

Since then I've been told about several other instances of cheaper thinner HDMI leads failing, from contact wear or sharp-bend fractures, and one duff connector on brand-new cheap unknown-name equipment (replaced instantly by C/PCW, no questions and not surprised).
 
OP
JefUK

JefUK

New Member
Thanks everyone for all your replies and suggestions.

Since the post I have done a lot of testing and analysis which supports my original thoughts that it is not an age related failure it is an inherent problem with my very early sample of the T2.

I purchased the T2 in early 2011 and the first one displayed the "green screen" on virtually every start-up. It was retuned as faulty. The replacement is the one I still have and was very much better but very occasionally has a "green flash" on start-up but always goes on to connect with the "old" TV. This "green flash" has not got worse over time. It points to a marginal timing problem. Its performance with the the other 3 TV's, although not as old as the T2 but of varying ages, has also not changed over time.

HDCP control is handled by both the receiver and transmitter chips. I believe that both chips are configured to work off their embedded oscillator, not from an external clock. Both of them have the HDCP parameters stored internally in a non-volatile OTP memory, but the receiver chip is also controlled by an external software driver for "easy updates". It is probably the receiver that will "decide" whether the display has valid HDCP.
As far as I know not all T2's suffer the "green screen" problem. This raises the question - is the problem confined to early versions? Did later versions have updated drivers? I know this question is difficult to answer because handshake involves two devices but does anyone know whether later versions of the T2 suffer the same problems as mine? If they don't it may be worth getting a a late model T2 and using the main board as a service replacement.

I know that it is not an economic repair.... but, out of pure interest, I might even consider replacing the chips - they appear to be still available! Unfortunately Humax will not release any circuit design or service information.
 
OP
JefUK

JefUK

New Member
As a matter of interest, did you buy the Aura as new or refurbished? I can't comment on COM7 reception because I receive from a local transmitter that doesn't carry COM7.

I have a vague recollection that someone reported fixing the green screen issue with a new TV by changing a setting on the TV; I think it might have been the HDMI version.
I tried two new Aura's they were both the same.

The HDMI inputs have two modes - Mode 1 for older devices and Mode 2 for newer ones. Mode 2 always displays the video, but no sound. Mode 1 displays video and audio but on only about 5% of start-ups
 
OP
JefUK

JefUK

New Member
Hmm, an off-the-wall obvious thought, I assume you have tried a few nice, clean, shiny new HDMI leads? And blown the fluff out of the sockets?

The year before lockdown I was asked to look at a brand-new audio extractor box that refused to pass the HDMI from the CD/Blu-ray (no analogue output) on to the owner's TV, black or green screen being among the symptoms.
We tried six different known working (without the box in the way) HDMI leads, but no two worked via the box.
The box did extract the audio with one lead, the one that was tight as tight can be, and that gave the green screen with some of the others on the output side.
Careful examination of both in and out HDMI connectors in the box revealed a lack of gold and quite a lot of tarnish. We probably used its lifetime count of insertions that afternoon!
Our conclusion was that either the box was unable to pass the HDCP handshake, or the HDMI connectors were useless, or even both. It was binned, being too cheap to bother with returning to Az, and an spdif to analogue converter bought instead.

Since then I've been told about several other instances of cheaper thinner HDMI leads failing, from contact wear or sharp-bend fractures, and one duff connector on brand-new cheap unknown-name equipment (replaced instantly by C/PCW, no questions and not surprised).
Yes tried 4 different HDMI cables. The TV is brand new.
 

Black Hole

May contain traces of nut
Surely this identifies the TV as the problem, rather than the numerous Humax units you've tried (of differing models) all with the same result.

The problem with HDCP (and HDMI in general) is that it is not a rigorous standard backed by a standards body, it os a hotch-potch brewed up by a club of manufacturers all with their own axes to grind. The resulting specifications are open to interpretation, and if one manufacturer chooses to interpret it one way, while another chooses a different interpretation (or worse: a different revision of the spec), incompatibilities ensue.

Buy a Toshiba player and a Toshiba display, and you can be pretty sure the combination is going to work, because (a) Toshiba have a vested interest, and (b) Toshiba will be designing to their own specific interpretation. Match a Humax with a Panasonic and, well...

out of pure interest, I might even consider replacing the chips - they appear to be still available!
A fool's errand. How many units have you tested? They all contain these chips (or similar). Are you saying all the units you tried contain out-of-spec chips? And even if they are available, how much expense are you prepared to go to to obtain them in one-off quantities?

You must realise there is much more involved in HDCP than the HDMI line interface. How can you point the finger specifically at the line interface chips when it could be the HDCP protocol handling in the SoC? You will only make informed progress (instead of pinning the tail on the donkey) by putting a 'scope (preferably an analyser) on the HDMI link and watching what happens (in conjunction with the HDCP spec – which is unavailable unless you spend a fortune to join the HDMI club).

Unfortunately Humax will not release any circuit design or service information.
Of course not, but if you look through the aforementioned hardware investigation thread you'll find a link to a reference design for the Broadcom PVR SoC.
 
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bottletop

Active Member
For my first HDR, the green screen issues was intermittent before it became permanent.

The replacement HDRs use the same TV, HDMI socket and cables and seem ok so far. They do have a green screen flash (split second) during power up.
 

sine24

Member
I had the odd green screen with previous TVs still got the same T2 unit and with the new TV the GS is gone forever.
 

trog

Active Member

@JefUK


" Mode 1 for older devices and Mode 2 for newer ones. Mode 2 always displays the video, but no sound."
Were both units set up for ARC and was an ARC capable HDMI lead used? The internet is full of people having issues with ARC and the usual solution is to change the settings and add an optical cable to provide the sound and let HDMI just deal with video.
 

erne

Member
I have had to buy a Manhattan T3-R. The Manhattan does exactly what it is designed to do and does it well - but unfortunately I prefer the T2
I really like the Manhattan T3-R. Interface really fast - Only issue I can see on this box is the inability to search the programme guide - (unless I have missed something) Search of on demand works well though - The best DVB-T box out there now in my opinion - Everyone I know who has the Aura has had issues :(
As for the T2 HDMI green Issues when I have had them in the past as others have mentioned cable issues are generally the culprit
Is there a possibility of passing the HDMI via a sound bar or Surround system which may help cure issue
 

rodp

Member
Very similar experience for me. If you catch the humax at the wrong moment it can green screen the TV (ie the order in which you turn them on). But changing the TV source to another port say form HDMI1 to HDMI2 and then back to HDMI1 resolves it for me. I have a bigger issue in that sometimes (if the box has been left on and the tv turned off and then back on a little while later perhaps after the T2 has been doing some recording and then stopped (but still on) the signal / handshake can be lost altogether so you just get a black or blank screen. When you put the humax into standby the tv knows something has changed and switches to a different port but when you bring the humax back out of standby the tv switches back to HDMI1 but again it's a blank screen and no audio either. My work around is either let the humax shut down fully (ie orange ring) then restart it or.... use my scart cable!! old tech!! it works though and we only record in SD so don't really notice the reduction in quality for the short time that the HDMI port is down.

I have however thought whether it's possible to use some sort of HDMI conditioner or repeater and whether that would keep the sync better. Does anyone have any thoughts on that and whether they are available?

Thanks

Rodp
 

/df

Well-Known Member
...
Looking at the T2 PCB the HDMI transmission interface is done by two quad flat package IC’s (DA9984A/15/13 and DA19977A/15C129). The DA19977A is an HDI receiver with HDCP, while the DA9984A is the receiver.
...
As explained here.

There was this thread last year. HDMI issues are typically resolved by using a non-HDCP-conforming HDMI switch.
 

Black Hole

May contain traces of nut
But changing the TV source to another port say form HDMI1 to HDMI2 and then back to HDMI1 resolves it for me.
My JVC shows "no signal" (on black) on start-up, in rashes. I cure it by switching to DTV and then back to the relevant HDMI. It has just occurred to me this might be the green-screen issue but the TV interprets that as no signal.
 

rodp

Member
As explained here.

There was this thread last year. HDMI issues are typically resolved by using a non-HDCP-conforming HDMI switch.

Do you have any suggestions? Seems to be loads on amazon but they don't seem to say much about HDCP. Is there anyone who has one and is tried and tested? What's the make and model if so?

Thanks

Rodp
 
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