SatCure satellite scart peritel lead connection FAQ

Unfortunately, I can't answer questions about connecting up specific equipment because various manufacturers set their own standards and I simply don't know them all. You should read the following information. If you still can't figure it out, try the links below. Otherwise, you may need to call in a specialist. Or you may be able to enlist help in one of the discussion forums where people with expertise in this field (or the same equipment as yours) will know the answer.

You can get connection help here:
http://www.dtg.org.uk/consumer/connection_wizard.html

and here:
http://www.radioandtelly.co.uk/connecthelp.php

A Scart system works by detecting 12 volts on pin 8. In other words, if, say, the VCR is ON then it puts 12 volts on pin 8 to tell the TV "here I am - look at me". Likewise the Sky Digibox does the same. if it's ON it invites the TV or VCR to look at it by putting 12 volts on pin 8 (or 6 volts if widescreen transmission).

Obviously, if you have more than one piece of equipment running at any one time, they will be fighting for attention. The answer is to switch one off or to disconnect pin 8 and select it manually ("AV in") when required.

Alternatively, use one of our Scart Switching boxes to select manually the input that you require.

Interference may be caused by video breakthrough.

	Cheap and cheerful Scart lead on page 4.
	High quality lead with gold-plated pins. Click HERE for more info.

"Scarting out Right"

To some installers, a Scart lead is a means of earning an extra tenner on each installation; to others it's a nightmare. Scart leads come in various lengths and types but the main two subdivisions are "fully wired" and "part wired."

The scart system was developed some years ago before satellite receivers and decoders were considered. For this reason, just one connection (pin 8) is used for signalling purposes. The intention was that a video recorder (for example) would put a "here I am" voltage on pin 8 when it was switched to "play." The TV would respond by showing the video signal (from the Scart lead) instead of the terrestrial picture from the aerial input. The main advantages of the Scart connection are that the picture is "cleaner", because it doesn't go through a modulator then a demodulator, and stereo audio is also possible, together with surround sound when available

Dolby Prologic (when transmitted) is encoded onto the normal Right/Left audio channels on pins 1 and 3 respectively. All you need to do is to connect these to a D.P. decoder. If there isn't one built into the TV set then you'll need a separate one, usually incorporated into an audio amplification system..

The Scart system gives a problem if, for example, the Scart lead is used to connect a DVD player to the TV. Now whenever the DVD player is on, it puts a voltage on pin 8, which makes the TV switch the DVD picture in, even if you don't want it to! Even worse - if the DVD player is ON but not playing, you may see just a blank screen - very confusing! The only answer is to disconnect the wire from Scart pin 8 and use the TV "AV" button to select the DVD picture only when it's wanted. If you have in addition a Satellite Receiver and a Terrestrial Digital receiver then you have major problems

Video breakthrough: Another problem which arises is that there can be signals or interference emanating from the TV on the Scart wires. This can cause "ghosting", "shadows" or lines on the picture. Pin 19 (at the TV end) is a likely candidate and should be cut, otherwise picture interference or "ghost pictures" may occur - often of the terrestrial programme behind the satellite programme. If you can't get inside the plug to cut the wire, simply twist the pin off (at the TV end). On most plugs you can use a sharp point to press the tiny tag on the flat pin which will let you push it inside the Scart plug. That way, if you get it wrong, you can tease out the tiny tag to lock it and push it back again. You can safely disconnect pin 19 (at the TV end) for any equipment that is sending its video TO the TV set and not expecting to receive a video signal back. For example: a Sky Digibox or a Freeview receiver.

Picture distortion may occur if the satellite receiver or decoder is incompatible with the TV or VCR. Occasionally the video level from the Scart connection is too high for the TV or VCR to accept. The answer is to modify a Scart lead in advance and to keep it in the van. The last thing you want is to have to solder in the customer's living room! You will need two 1/4 watt resistor of value 27 Ohms and 47 Ohms. Disconnect the wire from Scart pin 20 (video in) and solder the 47 Ohm resistor from pin 20 to pin 17 (video ground). Solder the 27 Ohm resistor from pin 20 to the end of the wire which you cut. The resistors will reduce the video signal. Mark the modified end "TV". You can now use this modified Scart lead for testing purposes and, if it cures a problem, leave it connected and make another to put in the van later.

The same problem can occur with audio levels. I don't know the output impedance of a Sky Digibox but, assuming it's around 1k, this simple resistive divider network should work. It divides the signal in the ratio 180/1000 (about one fifth). The resistor values can be adjusted to suit your particular application. 1/8 Watt resistors can be used and will easily fit inside a Scart plug. You'll need two pairs of resistors. R1 is connected to Scart pin 1 (Right) and pin 3 (Left), with the wires that were connected to those pins going to the respective junctions of R1 and R2. "Common" goes to pin 4.

	Cheap and cheerful Scart lead on page 4.
	High quality lead with gold-plated pins. Click HERE for more info.

Audio breakthrough: faint audio getting through (usually from the TV programme) can usually be cured by cutting the wires from pins 1 and 3 in the Scart plug at the TV end (see diagram below). If you don't want to cut the wires you can twist the flat pins off. On most plugs you can use a sharp point to press the tiny tag on the flat pin which will let you push it inside the Scart plug. That way, if you get it wrong, you can tease out the tiny tag to lock it and push it back again.

A Digital Receiver is usually capable of providing Red/Green/Blue signals which can be fed to a suitable TV to give (in theory) better picture quality. However, a side effect is that on-screen menu graphics might roll and Teletext might be affected, too. The picture might shift to the left (due to delay line mismatch) or the contrast might be too high. The answer is to "TRY BEFORE YOU BUY" to ensure that your Digibox and TV are compatible. If not, buy a different TV.

You can pay more for a gold-plated Scart lead but what is the advantage? Well, unless the plug pins *and* the socket pins are gold plated, there is unlikely to be any advantage at all.