No picture from SFR TV decoder STBP-SGM-r2 on Panasonic TH-42PV500B

nickdc

Active Member
Would much appreciate some help on this - getting rusty in my old age!

I'm in France; I mainly use a more recent (6yrs?) Epson HD projector and I've just hooked the decoder up to that and to my surprise, it works fine. After long discussion with SFR technician I was convinced there was a problem with the HDMI out on the decoder box. But obviously not. So why does it no longer work with the Panasonic? Same cable that I hooked it to the projector with. Different ethernet cable, but the SFR lady confirmed remotely, and the modem/router SFR box interface confirms, TV connected. Only one HDMI port on the TV (very early model) so I use a switcher, but ruled that out by connecting direct, decoder to TV. I'm assuming there's some incompatibility between the signal emitted by the decoder and the receiving TV, but other fairly recent devices (eg a Sony smart blu-ray player) work fine. Until I found it worked on the other system with the projector, I was convinced the HDMI out on the decoder was faulty. Now I'm simply flummoxed.
 

mikej

Well-known Member
What signal resolution does the SFR decoder output ? Page 6 of the 42PV500B's service manual contains a table which shows the supported resolutions and the top 8 entries are the ones supported by HDMI, so that's the first thing I'd check.
 

nickdc

Active Member
Thanks for responding Mike. Yes, I still have the manual for the TV and have looked at that table, but I can't find much about the decoder's output. Just this:

Quelles sont les caractéristiques détaillées du décodeur TV Évolution​

  • La connectique
    Votre décodeur TV Évolution dispose des prises suivantes :
    • 1 prise coaxiale DVB-T d'entrée et une de sortie (Antenne/TNT),
    • 1 prise TV, et 1 prise auxiliaire (péritel),
    • 1 prise Cinch L/R, 1 SP/DIF (son),
    • 2 prises Ethernet RJ45 (réseau),
    • 1 prise HDMI compatible HDC (téléviseur HD),
    • 3 ports USB dont 2 au dos du décodeur : la prise USB 3 HDD est spécifiquement conçue pour connecter un disque dur externe ne possédant pas d'alimentation.
Il est en outre équipé d’un disque dur interne pour l'enregistrement et contrôle du direct.
Pour les abonnés Fibre Multi room, le second décodeur est livré sans disque dur ni tuner TNT.

  • Les formats audio et vidéo supportés
    Décodage vidéo
    • MPEG-4
    • WMV9/VC
    • MPEG-2
    • MPEG-1

    Décodage audio
    • MPEG-2/4 AAC
    • MPEG-4
    • MPEG-1/2
    • WMP9/pro
    • Dolby Digital 5.1 Plus 7.1, Lossless 7.1
    • DTS, DTS-HD
I think most of this is comprehensible even though in French. "Péritel" is the French term for SCART. And that suggests to me that it surely ought to be compatible with an older TV. Come to think of it, I may have some old SCART leads lying around; maybe I should try connecting with them, as the TV has a SCART input. Picture probably a bit rubbish, but would be interesting to see if it produces something.
 

mikej

Well-known Member
When you said "So why does it no longer work with the Panasonic?", does that imply it used to work ? If so, then presumably there's a fault somewhere. If not, and you have confirmed that the SFR decoder is outputting to other devices OK and that other devices plugged into the TV via HDMI work fine, then I would have thought the most likely explanation is that the decoder is outputting a signal resolution that the TV can't accept.

As the decoder doesn't appear to have an DVB-T2 (HD) tuner, you probably don't have much to lose by trying scart.
 

nickdc

Active Member
When you said "So why does it no longer work with the Panasonic?", does that imply it used to work ?
Embarrassed to admit that I'm really not sure! It was a replacement for an earlier box that definitely broke. Already by that time we had the projector installed in another room and hardly ever used the plasma tv. And in any case, hardly any French TV. But with covid, and wanting to follow French news more closely I decided to bring it back into use, only to discover there was no picture. Very busy at the time so just left it. Now, 18 months on, would really like to get it operational, but genuinely unsure whether this did work when first installed. It's entirely possible it never did, though more probable that it did, otherwise why didn't I send it straight back? But my wife had a stroke in 2018, and since then priorities have entirely changed.
I tried with SCART this morning, but same result. The TV clearly knows it's there, as the change of input from HDMI to AV1 RGB was briefly flagged up on the screen.

I agree that incompatibility of signal is most likely diagnosis and I'm wondering if these days there might be some whizzy little converter box that would go between the two devices to make them compatible. (We really don't want to ditch the Panasonic plasma, which, given we're not into 4K or beyond, still to our elderly eyes gives a much nicer picture than the new kit our grown-up kids now have.)
 

nickdc

Active Member
Wondering if this might assist diagnosis: although the HDMI cables I've been trying are relatively recent purchases and work fine with other devices, I've received a brand new cable this morning (bought for another device), so thought I'd try it between the Panni and the SFR box. For a brief moment there was a flickering picture. It lasted only a few seconds and never stabilised, but I was able to see it was definitely from the SFR decoder. This new cable is 4.5m, so I'm wondering if the length could be an issue? (All the other cables have been shorter anyway.) Any thoughts?
 

mikej

Well-known Member
I doubt HDMI cable lengths are an issue from what you've said so far and if it's only a 1080p (max) signal you're wanting to carry, then the HDMI cable spec shouldn't be an issue either. Just make sure the cables you're using are of a decent quality and work by testing them with other sources.

Have you checked the video output options on the decoder ? Most external sources allow you to change the output signal resolution. Scart won't carry an HD signal, but I'm not sure if you'd have to lower the resolution in the settings in order to use scart or whether the decoder would do that automatically but it's worth looking into. The decoder remote may even have a button for this but if not, then you'll have to connect it to a display it works with, such as another TV or your projector. Just make sure you choose a resolution that the other displays will handle to avoid getting stuck !
 

nickdc

Active Member
I remembered late last night that we have another TV, a Sonia Bravia, in an adjoining annexe, so this morning I hooked the decoder up to that, and it worked fine, so presumably the problem is more with the Panasonic. I had a good play with the decoder while it was hooked up but couldn't find any way to change the output signal. No real settings options at all - it's pretty basic, as is the remote.

I also found an SFR forum yesterday and interestingly one of the things some people are flagging up is "écran noir" (black screen), just like I'm getting with the Panasonic. It's a sparsely populated forum with little discussion and there are no solutions offered. Also no way of knowing if people are trying their boxes with a variety of devices or a single TV. But it's got me thinking there may be some sort of fault with the decoder that's just triggered when it encounters a particular combo of circuitry and/or firmware in a display. I don't have the expertise to know if that's a possibility or not, hence the appeal here to folks with a better knowledge of the electronics.
 

mikej

Well-known Member
Yes, it does obviously sound like some kind of incompatibility between the two.

How old is the decoder ? A lack of HD tuner and presence of a scart socket would make it at least 10 years old I would have thought. With a relatively simple device like that which lacks options to adjust even basic settings like the output resolution, then I'm instinctively thinking that you might struggle to find a solution. You might be better off upgrading to something a bit more modern that'll give you less issues ?
 

nickdc

Active Member
It's not that old. I just checked some diary notes and it looks as though we got it in 2017. Scart stayed in use over here quite a bit longer than in UK/US. The trouble is, it's all part of an internet/phone/TV package and the box technically belongs to SFR. If past experience and others' testimony is anything to go by, I'll have a hard job persuading them to replace it if I can't prove it's faulty. And until our locality is eligible for fibre or other high speed service, we're stuck with standard ADSL and the kit that goes with it, unable to upgrade to anything different to what we have.
I'll have a shot though. Some of their service personnel are much more helpful than others and I might strike lucky. And I should at least be able to find out details of the models they send out now to new customers and argue we're due a more recent model.
Another option of course would be to swap the plasma Panasonic for the Sony Bravia, but I'm very fond of the Panasonic so reluctant to do that.
Again, many thanks for your thoughts. I appreciate your hanging in there on the case!
 

nickdc

Active Member
Success at last! Although for testing I was connecting the decoder directly to the Panasonic's single HDMI input, until I began the troubleshooting It was connected along with one or two other boxes via an HDMI switcher. The latter is old (though the best I could buy in those days), but only has 3 inputs, the SFR decoder taking the third. I've just bought another piece of kit for that room, so have bought myself a new (5 port) switcher, and - hey presto! - the SFR decoder works again through that! I imagine therefore the switcher doesn't simply channel the signal to the output port, but must do some enhancing in the process? Delighted it works, anyway!
 

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