SCART confusion - help please

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geekIT

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#18992 1-Feb-2008 00:24

I'm trying to make up a 4m lead (SCART male to SVideo, right audio, left audio) to go from my Pace decoder to my home theatre system.

I'm confused because I already have an old 1m (SCART to SVideo, right audio, left audio, composite video) lead that works, so I thought I'd copy its configuration, but its pinouts seem to be different from every diagram I've found on the net.

The config. is as follows: (I'm not sure which of the SVideo wires are chrominance and luminance so I'll refer to them as A and B. They're actually red and white)

Pins: Audio
1-Right audio out (seems correct)
3-Left audio out (seems correct)
2-Right and left audio (combined) ground (seems like this should be pin4??)

Pins: Video composite
19-Video signal
18-Video ground

Pins: SVideo
19-'A' signal (shares with Video signal)
13-'A' ground
15-'B' signal
18-'B' ground (shares with Video ground)

As I said, I've used this old lead to connect my decoder SCART (the SCART socket marked 'TV') and my television set, and it works.

But everything I'm reading tells me that this layout is incorrect. Several different diagrams seem to indicate that my new plug\lead should be wired like this:

Pins: Audio
1-Right audio out
3-Left audio out
4-Right and left audio (combined) ground

Pins: Video composite - not required

Pins: S-Video
15-Chrominance IN (A or B signal?)
13-Chrominance ground
20-Luminance IN (A or B signal?)
18-Luminance ground

Advice would be most appreciated :-)

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cyril7

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#107902 1-Feb-2008 08:18

A correctly wired SCART to S-Video output cable (note direction is important) should be

Audio:
1 Right Audio
3 Left Audio
4 Audio Gnd

S-Video:
19 Luma
17 Luma Gnd

15 Chroma
13 Chroma Gnd

Pins 19/17 are infact the composite out, when operating in S-Video this becomes Luma out, and the Chroma is sent on the Red channel.

SCART has a composite in and out circuit, aswell as audio in and out. When in S-video mode the Luma remains directional and is sent on the composite out channel, the chroma is not directional. A display that support S-Video in on a SCART would accept S-Video in on pins 20/17 (composite/luma in) and 15/13 chroma/red.

The RGB channels can be either in or out. When in RGB/Component mode the composite circuits and their directional channels are kept in tact. In RGB mode the composite out is used to sync the display, when Component is output the channels are assigned G=Y, R=Cr, B=Cb and the composite channel remains although not needed for sync as that is carried on the Y channel.

As you can see, a complete dogs breakfast.

Cyril

geekIT

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#107909 1-Feb-2008 08:52

Cyril7, thanks very much. I should be able to construct my lead from your instructions.

And I think I'll just accept what you've said, rather than try to understand the logic and rules of SCART, much as I'd like to. At 67 I find that I have to make choices about how much brain space to allot to each subject :-)

(But I'm durned if I can see why my antique (over 25 years old) lead that I described above, works.)

Just one further question, if you would.

How can I identify which wire is which in an S-Video cable? As I said, the S-Video section of my old lead has two shielded wires, one red and one white. Is this a reliable indicator of Luma and Chroma?

Or can you tell from my description of the old cable which is which?

Again, much thanks....

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cyril7

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#107913 1-Feb-2008 09:04

The wiring of your old cable is just fine, the only real issue is that the earths are connected to non standard pins (ie other pins that are also earth but not the offical earth for the matching circuit), presumably for wiring convience. However if you were to look at the wiring on the SCART socket of the STB PCB you would probably find they are all just a mass earth, so it all works without problems.

Dunno which way around on S-Video plug, I always get confused, and normally end up plugging the S-Video plug into a DVD and look at the signals on each with my CRO to see if its chroma or Luma. But checking with a working one will help, ie which pin of the S-Video plug goes to SCART 15 and 19 will soon identify it.

By the way Ian did you sort your Sky upgrade ok, (from the other thread a few days ago)

Cyril

geekIT

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#107925 1-Feb-2008 09:24

OK, Cyril, that outta do it, cheers :-)

RE the SKY upgrade, the guy turned up to do the job but, as I should have expected (being a cynical old b****r), the SKY office hadn't told him that I'd ordered a Motorola unit, so he didn't have one on his truck.

Anyway, he reckoned that there wasn't a lot of point in replacing the Pace, so he just went into its config and set it for SCART (prior to that, the old lead was obtaining audio and B+W picture only), so that's where it's up to.

Only thing I want to do now to finish my Home Theatre rig is to get me a Freeview STB and scart it into my Sony DVD recorder on the SVideo, L+R audio in, and I'll have a very versatile setup.

Hence my interest in building the 4m SCART lead; in fact I need two of 'em.

Once again, many thanks for your helpful expertise

'Those who can make you believe absurdities can make you commit atrocities.' Voltaire

'A patriot must always be ready to defend his country against his government.' Edward Abbey

geekIT

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#108387 4-Feb-2008 00:53

Hi all, especially Cyril.

My SCART leads work fine, thanks to Cyril, who previously said:

"Audio:
1 Right Audio
3 Left Audio
4 Audio Gnd

S-Video:
19 Luma
17 Luma Gnd

15 Chroma
13 Chroma Gnd"

This pin arrangement worked perfectly for my DIY SCART-to-SVdeo+left and right audio cables. I ended up using SVideo cable for both the SVideo and the audio, as my supplier had run out of 5 metre SVideo cables and sent 10 metre instead (for the price of 5m).

All I need now is my Freeview STB and the rig will be complete.

Thanks to all who've weighed in with their helpful advice on all my questions.

'Those who can make you believe absurdities can make you commit atrocities.' Voltaire

'A patriot must always be ready to defend his country against his government.' Edward Abbey

geekIT

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#112718 24-Feb-2008 16:34

Hi again, all.

I now have a FreeView decoder. It's an "Aetna" which I purchased on TradeMe ($80+ freight etc).

It seems to work fine if I use its Video, Left-Right audio RCA outputs.

But I'd rather use its SCART socket.

This way, I can connect it to my SONY DVD recorder, and use the SVideo function of the SCART output. (if it's there on the Aetna)

Earlier, I'd built two SCART leads for my new Home Theatre system. Each lead goes from SCART to SVideo, Left audio, Right audio.

Either of these leads works fine with my SKY decoder.

But not with the Aetna decoder - I can get left and right audio OK, but the picture is black and white.

The vendor (who apparently sells heaps of these gadgets on TradeMe) hasn't responded to my queries on this subject, so far, (although he's been pretty good with respect to other after-sales-service issues) so I'm wondering if he actually knows the answer...

Anyone able to comment on this? Seems to me that the options are 1>Bad lead (but it works with the SKY decoder) or 2>The Aetna decoder has a different SCART pinout.

Advice would be appreciated :-)

'Those who can make you believe absurdities can make you commit atrocities.' Voltaire

'A patriot must always be ready to defend his country against his government.' Edward Abbey

cyril7

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#112726 24-Feb-2008 16:46

Hi, are you sure the Aetena supports S-Video, I have no expericnce of that brand but most cheaper STBs with SCART only support composite and RGB, if its not a menu option it may not support it.

Cyril

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geekIT

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#112732 24-Feb-2008 17:06

Cyril, no, I don't know if the Aetna supports SVideo. The vendor hasn't replied to my query so maybe this means that the decoder doesn't have the facility.

However, I dunno if it's a real BFD as the picture is excellent via regular video. I just wondered if I might have done something wrong with my newly constructed SCART to SVid,L,R audio cable.

Thanks again Cyril :-)

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cyril7

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#112736 24-Feb-2008 17:20

Hi, just checked out the aetna on tardme and I have seen these boxs before, and am pretty sure it does not support S-video only composite and RGB, if there is no menu option to select betwteen RGB and S-Video then you can bet it dont do it.

It also does not support 4:3Letterbox, only 16:9 and 4:3CentreCut, hence I have avoided them as budget boxs are normally sold to folk with older 4:3 TV's, its no good if it does not support 4:3LetterBox.

Cyril

geekIT

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#112844 25-Feb-2008 09:44

OK, no prob - did a quick mod on my SCART connector and changed the plugs to RCA Video, left,right audio and all is now well.

I didn't know that about the Aetna's output format, but it's no BFD. I mean, I only have a CRT set anyway, a TEAC 60hz behemoth that I bought for $900 from Noel Leeming two years ago when my wonderful Panasonic SVHS TV died.

It seemed obvious even then that it wasn't the time to buy a humungus LCD or PLASMA screen, and I still think its a little early, as there's a lot of developments in the pipeline and a heap of new hardware on the drawing boards.

So the TEAC will do fine for a while. Plus, I understand that TVs are likely to have built-in freeview decoders in the not too distant future, so when I finally buy a big screen, the Aetna can be retired. Actually, its picture is better than the one from the SKY decoder.

Thanks again Cyril

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'A patriot must always be ready to defend his country against his government.' Edward Abbey

cyril7

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#112846 25-Feb-2008 09:47

Hi, the main reason your new box most likely has a better picture than the sky one is not so much the box but the fact that TV1,2,3 off sky are via Skys muxs that have much lower bit rate than the FreeView service muxs.

Cyril

geekIT

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#112887 25-Feb-2008 11:48

Oh, OK. Which makes sense of the rumours that SKY will probably dump the freeview channels soon?

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openmedia

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#112911 25-Feb-2008 12:54

geekIT: Oh, OK. Which makes sense of the rumours that SKY will probably dump the freeview channels soon?

So what freeview channels is Sky planning on dumping?

Generally known online as OpenMedia, now working for Red Hat APAC as a Technology Evangelist and Portfolio Architect. Still playing with MythTV and digital media on the side.