Scart To S-video Colour Problems Solved

[stingdt]

Foxtel finally turned up a few weeks ago to replace our Analogue STU with a new Digital UEC unit. However, the installers must have been feeling a bit lazy, as they left it connected to the TV through RF (Ugghh!)

Anyway, decided to re-cable it for a better picture. The TV it's currently connected to is an older CRT unit, which only supports S-Video and composite (no component). The UEC box can output S-Video through SCART, so I got one of the in/out switchable SCART to 3xRCA and 1xS-Video adaptors from Dick Smith (P 6675). I then ran an S-Video cable from the adaptor to the TV's S-Video input.

However, the colour in the picture was really strange. The picture was essentially black-and-white, except for some areas of really strong colour, which appeared with normal colour. E.g. Bright reds, blues and greens showed up OK, but skin tones, etc. were completely missing.

It turns out that Cyril had the right idea in this post. It seems that my TV doesn't terminate the Chroma channel properly, and needs an additional termination resistor.

The DSE SCART adaptor can easily be modified to work properly. First, open the adaptor with a small flat-blade screwdriver (insert the screwdriver into each of the four holes on the bottom of the adaptor, and release each clip one by one). Next, find the two wires attached to pins 13 and 15 of the SCART connector (Chroma signal and Chroma ground). These wires should run to two pads on the small circuit board on which the sockets are mounted. Then solder a small-value resistor (I used a 200 Ohm resistor) between these pads. I.e. The resistor will bridge the Chroma signal to Chroma ground. Make sure the resistor legs aren't going to short anything, and clip the connector back together.

If all goes well, your video should have the correct colours now. It worked brilliantly for me, but YMMV. Don't blame me if anything blows up :-)

I thought I should probably re-post this as it's own thread, in case anyone else has trouble getting their STU working properly on a mis-behaving S-Video TV. I think it would also be good to have this in the FAQ to make it easier for people to find it. Although S-Video will likely become obsolete soon, with most new TVs having Component inputs. (I was told by DSE that the official Foxtel SCART to S-Video cable is no longer being sold...)

I'd be interested to hear from anyone who has had the same problem, and if they were able to fix it in the same / a different way.

Thanks for all the useful support guys.

[cyril]

Since I post that last linked post I have corrected quite a few setups with this issue. I have since found that you can actually getaway with a resistor loading as little a 1kohm and it still provides sufficient DC loading, however causes less loading of the chroma channel itself. Not a real issue as the PAL decoder in the TV/display will AGC onto the reference burst and compensate.

I have found Panasonic TVs and panels and Pioneer Plasmas panels to be among the most common I have dealt with.

Cyril

[Jards88]

Since I post that last linked post I have corrected quite a few setups with this issue. I have since found that you can actually getaway with a resistor loading as little a 1kohm and it still provides sufficient DC loading, however causes less loading of the chroma channel itself. Not a real issue as the PAL decoder in the TV/display will AGC onto the reference burst and compensate.

I have found Panasonic TVs and panels and Pioneer Plasmas panels to be among the most common I have dealt with.

Cyril

Cyril,

My Samsung LA26 LCD works perfectly with the UEC box using S-Video without modification, so I guess I'm one of the lucky ones.

Cheers, Ian

[wheelz]

I know its a silly question,did you change your fox stb to output s-video in the"video output" menu first?(if you dont it will give B&W pic)

[stingdt]

I know its a silly question,did you change your fox stb to output s-video in the"video output" menu first?(if you dont it will give B&W pic)

Yes, changing the video output on the STB was the first thing I tried. Strangely enough, I don't get a B/W picture with the other video modes. The colour just gets really washed out, and sloping lines run through the picture.

Should probably also mention the TV is an 80cm Sharp SX80J7 CRT (bought back in the days when you could get a reasonably sized car for the cost of an LCD/Plasma.)

[wheelz]

I know its a silly question,did you change your fox stb to output s-video in the"video output" menu first?(if you dont it will give B&W pic)

well it now seems i have the problem mentioned,i just bought a pioneer 540 dvd-r,and connected it up using s-video and blow me down i get the mainly b&w pic with a few colors.Now the thing thats got me stuffed is im using the other scart output from my fox stb to my amp using s-video and all is perfect.Any ideas

cheers

[cyril]

Wheelz the issue you are seeing is exactly the one I refered to above. What is most likely happening is that your AVR terminates the Chroma channel correctly thus when S-video is passed through it, it works OK, however your DVR is not correctly termintating it.

I assume if you swap TV and VCR SCARTs the exact issue arises.

Cyril

[wheelz]

Thanks for the reply Cyril,i have read you fix and to be honest it goes straight over my head and having limited use of my hands (quadraplegic)wouldnt help either,is their a simple plug/adaptor already modified i can buy that would fix the problem?

cheers

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(I was told by DSE that the official Foxtel SCART to S-Video cable is no longer being sold...)

.

Did the offical fox-scart lead fix the problem?

[405Mi16]

I'm running the set-top box to a Denon AVR-1801 Amp. Using a SCART to S-Video cable, I get nothing, no output whatsoever, no picture on the screen, no audio from the amp...Composite RCA works fine...Setup is set to S-Video, any idea?

EDIT: Just concluded that the SCART > RCA cable works, but not the SCART > S-Video...wierd.

Edited December 28, 2006 by 405Mi16

[llama_boi]

EDIT: Just concluded that the SCART > RCA cable works, but not the SCART > S-Video...wierd.

The cable is directional so make sure you've purchased the correct cable. Another option is buy those adapters which let you switch the direction of the signal.

[405Mi16]

The cable is directional so make sure you've purchased the correct cable. Another option is buy those adapters which let you switch the direction of the signal.

hmm. it's almost as if s-video isn't even enabled on the box itself, it just does nothing. it's a foxtel digital set top box, they all have it enabled yeah? there is no s-video connector on the back, so i'm assuming scart is the only way it works...

[stingdt]

Wheelz: I don't know if the official SCART to S-Video cable would work or not. They aren't on the Dick Smith website, making me believe they have stopped selling them. The Foxtel website says the accessories are also sold at Harvey Norman, The Good Guys and Domayne. They might still stock the S-Video cable.

The only difference with the Foxtel cable, versus a generic SCART to S-Video cable, would be if the Foxtel cable had a terminating resistance built in. Seeing as how I haven't tested one, I have no idea if this is the case. Although, if you were to buy one and it didn't work, I assume you could then refund it and/or call Foxtel support.

405Mi16: SCART is directional, so you have to make sure you have a cable to take SCART output to S-Video input, not a cable intended to connect S-Video output to a TV with SCART input. The DSE adaptor I mentioned has an in/out switch to change between the two. To adapt the SCART output on the cable box, the switch should be in the "out" position, or you will get no video at all. As mentioned, you also need to select the correct output in the box software menus, but at least for the UEC box, I get some output on S-Video regardless of which setting is selected.

Two more things - First, If you run your Foxtel into the S-Video on your amp, you also need to connect the S-Video monitor (output) on your amp to your TV's S-Video input. And the same for composite. I.e. At least for my amp, it will not switch S-Video inputs into Composite output, and will not switch Composite inputs into S-Video output. If you have both Composite and S-Video inputs to your amp, you will most likely need to connect your amp to your TV using both Composite and S-Video connections, and select the correct input on your TV depending on whether you have an S-Video or Composite source selected via the amp. The easiest thing to do is to connect all your devices to your amp using the same type of connection if possible. E.g. All Component (if you amp and TV supports this) or all S-Video, to avoid having to switch TV inputs.

Second, S-Video does not carry audio, only video. For audio, I have connected the S-PDIF output on my UEC box to the Coaxial Digital-in on my amp. For the Pace boxes, I believe you need a 3.5mm mini-optical to TOS cable (Dick Smith CA1003). This will give you digital sound on all channels, and Dolby Digital on some movie channels (E.g. Showtime and FBO).

Sorry for the long post. I suppose the above will be obvious to some, but they can be traps for the unwary.

[festy1]

Just for anyones info, foxtel digital scart output to s-video works fine with a jaycar SCART PLUG TO 3 RCA & S-VHS SOCKET ADAPTOR CAT. NO. PA3659 and an s-video male-male cable. Trick for new players is to change the foxtel digital box setup in the menu to output s-video and all of a sudden magic colour.

This is working ok for me on a hauppauge pvr-150 mce low profile edition both sound and video

[Supaturd]

Hi,

Im new to this forum and all this digital tv stuff.....

Im having the exact same problem as all of you with my pioneer DVR-540 that i bought yesterday.....

my original samsung dvd recorder works perfect but then when i connected my pioneer the s-video was black and white with some colour and the rca picture was total crap....i have all the settings correct

the set up i have is.....from the pace foxtel box i got the scart cable to s-video into the back of the recorder then component from the recorder into the back of my 32' LCD.

i was all excited to use this yesterday and i couldnt get the pic out of it.....is this setup i have correct???

just confirming what to do to fix it....like i said i know pretty much nothing about all this stuff....and all the soldering stuff has gone over my head

basically i just have to go to jaycar and buy 1 of those scart to rca and s-video adaptors, plug in the adaptor to the foxtel box, and run a male to male s-video cable to the dvdr????

and the adaptor with the in/out switch just flick it onto the appropriate tab and all should work???

is that correct???

thanks!

[cyril]

You say you already have a SCART to S-video cable from the Fox STB to the DVR, so why do you need another adpator.

As a test have you tried plugging the S-video (using current cable) directly into the LCD panel. Assuming this is all fine but still have an issue with going via the DVR then you may need to get a terminating chroma channel cable made.

Cyril

[Supaturd]

Hi Cyril,

Yep i have tried plugging from the STB to the lcd panel using component and s video and the pic is perfect....but when going through the dvr the pic is black and white.....

where would i get a terminating chroma channel cable made??

this is frustrating cause i wanna plug it through the dvr so i can record footy etc etc.....

You say you already have a SCART to S-video cable from the Fox STB to the DVR, so why do you need another adpator.

As a test have you tried plugging the S-video (using current cable) directly into the LCD panel. Assuming this is all fine but still have an issue with going via the DVR then you may need to get a terminating chroma channel cable made.

Cyril

[cyril]

If you dont know of anyone capable of undertaking such a task then I suggest that you go to your local TV repair shop and ask if they can do it for you.

You need to place a resistor across the chroma channel, I recommend a 470ohm resistor normally does the trick. Its easist to open the SCART connector and place it across pins 15(Red/Chroma ch) and 13 (Red/Chroma Ground). If you cannot work out which pins are which then its ok to place it across both the chroma channel 15/13 and another across the Luma channel 19/17, the S-video cable will lead you to these pins sets.

Cyril

[studiorambo]

Sorry to dredge up an old thread, but I had a question about picking a resistor to make a chroma grounded s-video cable for my foxtel to pioneer DVD recorder connection. In earlier posts Cyril recommended a 470 Ohm resistor, does this literally mean a 470 Ohm resistor, as in a yellow-violet-black-black resistor using the colour code? The OP used a 200 Ohm resistor, this would correspond to a red-black-black-black resistor, right? Am I misunderstanding resistor grading?

Would somebody kindly recommend the colour coding of an appropriate resistor for this task?

Regads,

[cyril]

200ohms would be fine, as is 1000ohms from my experiments is fine also. I also found that 2000ohms worked, however I decided that 470 was more optimal as it meant the chroma channel would experience less termination loss and 2000 may not provide enough DC restoration. That said the pal decoder has an AGC circuit that works on the chroma reference burst to compensate if the chroma channel is low.

Things to concider, the input circuit should be providing a 75ohm termination at the chroma channel frequency band (ie above 2-3MHz) its just DC thats not terminated. Therefore normally the termination loss is 6dB, this is the correct and normal loss. 220ohms would make the chroma have a 7.4dB loss, 470ohms would be 6.7dB, eitherway these are not dramatic losses that the AGC would readily make up. End result is any DC resistance upto around 2k will allow DC stabilitsation. I suggest anywhere between 220-1000, therefore 470 sounds good, but 220 would be good to.

Cyril

Edited October 17, 2007 by cyril