SAM Coupé

RGB Scart

Built-in
Submitted by Dan Dooré on Friday, May 25, 2018 - 13:29.

Description

The Coupé SCART socket to handle all video and sound outputs, note that not all connections are standard as it also has +5V and +12V inputs, TTL level ouput and a lightpen connection, perhaps the voltage lines were added to allow for a single cable to be connected to the Coupé as was shown in some of the marketing material of the time.

 

PIN SIGNAL PIN SIGNAL
1 AUDIO OUT RH 2 SPEN
3 AUDIO OUT LH 4 AUDIO EARTH
5 BLUE EARTH 6 BLUE TTL OUT
7 BLUE LIN. OUT 8 RED TTL OUT
9 GREEN EARTH 10 GREEN TTL OUT
11 GREEN LIN. OUT 12 +5V POWER IN
13 RED EARTH 14 CSYNC EARTH
15 RED LIN. OUT 16 CSYNC
17 C VID EARTH 18 +12V POWER IN
19 C VID OUT 20 BRIGHT TTL OUT
21 GND.    

Cable Details

When making a cable you will need to add a 470 Ohm resister between pins 16 and 20 on the TV side to prevent saturation of the signal.

Sam Pin Signal Cable TV Pin Signal
1 AUDIO R/H —— 2 AUDIO INPUT B
3 AUDIO L/H —— 6 AUDIO INPUT A
4 AUDIO EARTH —— 4 AUDIO EARTH
7 BLUE OUT —— 7 BLUE
11 GREEN OUT —— 11 GREEN
14 CSYNC EARTH —— 14 CSYNC EARTH
15 RED OUT —— 15 RED
16 CSYNC —— 16 BLANKING
      -/\/\/- 470 OHM RESISTOR (between 16 and 20)
      20 VIDEO INPUT
21 SCREEN —— 21 SCREEN

In recent years with widescreen and now LCD/Plasma televisions it is more important to feed a voltage into the standard SCART pin 16 (blanking), the above pin-out allows this but at the expense of stressing the CSYNC line - an alternative is to use a flylead to pick up the 5V line (not the +5V input line on the SCART which is wired before the internal power switch) from the Lightpen/Audio port and feed it through a 50R resistor to blanking get the required 1-3V to select RGB mode.