Interactive Connector Diagram
Click or tap any pin in the diagram below to inspect its signal assignment, electrical specification, and wire colour standard.
Click any pin to view its signal assignment, electrical spec, and wire colour.
Supported Systems / Found On — Retro Machine Hubs
This connector is used on the following retro computer systems. Click any colour-coded badge below to open its full board-level repair, diagnostic, and schematic Machine Hub:
Connector Specifications
Sinclair QL Socket
8-Pin 262° Horseshoe DIN (Outputs 5 V TTL R, G, B & CSYNC + Composite PAL)
Spectrum +2A / +3
8-Pin 262° Horseshoe DIN (Outputs TTL R, G, B, CSYNC & +12 V on Pin 5)
Spectrum 128K / +2
8-Pin 270° Circular DIN (Composite Video on Pin 1 + TTL RGB)
SCART Resistors
330 Ω on R/G/B (Pins 7, 6, 8) and 470–680 Ω on CSYNC (Pin 4)
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| 1 | PAL COMPOSITE VIDEO | Out | Composite PAL Video Out (QL, 128K & Grey +2; Mono/Bright on +2A/+3) | Yellow RCA (Composite) |
| 2 | GND (0 V) | GND | Common Video & Sync Ground | SCART Pins 5, 9, 13, 17, 18, 21 |
| 3 | MONO LUM / BRIGHT | Out | QL: Monochrome Luma | Spectrum 128/+2: Bright Bit | +2A/+3: Audio Out! | +2A/+3: SCART Pins 2 & 6 (Audio) |
| 4 | /CSYNC (TTL) | Out | 5 V TTL Composite Sync Output | SCART Pin 20 via 470 Ω resistor |
| 5 | VSYNC (QL) / +12V (+3) | Out | QL: TTL VSYNC | Spectrum 128/+2/+3: +12 V DC Output! | Spectrum: SCART Pin 16 via 330 Ω |
| 6 | GREEN (TTL) | Out | 5 V TTL Green Video Output | SCART Pin 11 via 330 Ω resistor |
| 7 | RED (TTL) | Out | 5 V TTL Red Video Output | SCART Pin 15 via 330 Ω resistor |
| 8 | BLUE (TTL) | Out | 5 V TTL Blue Video Output | SCART Pin 7 via 330 Ω resistor |
Sinclair QL & ZX Spectrum +2 / +3 RGB SCART Resistor Guide
The Sinclair QL and the 128K ZX Spectrum family share the same core 8-pin DIN RGB pin numbering for Ground (Pin 2), Composite Sync (Pin 4), Green (Pin 6), Red (Pin 7), and Blue (Pin 8), making it easy to build clean RGB SCART cables for both machines once you account for the TTL series resistors.
- Because both the Sinclair QL (ZX8301 ULA) and ZX Spectrum +2A/+3 output 5 V TTL logic levels on Red (Pin 7), Green (Pin 6), and Blue (Pin 8), solder a 330 Ω resistor in series with each colour line inside the SCART shell (Pin 7 -> 330 Ω -> SCART 15; Pin 6 -> 330 Ω -> SCART 11; Pin 8 -> 330 Ω -> SCART 7).
- Put a 470 Ω to 680 Ω resistor in series with Pin 4 (CSYNC -> SCART Pin 20).
- On the ZX Spectrum +2/+3, wire Pin 5 (+12 V) through a 330 Ω resistor to SCART Pin 16 to enable RGB blanking. On the Sinclair QL (which has no +5V/+12V pin on its video DIN), either feed SCART Pin 20 from Pin 1 (Composite Video) and derive +5 V from a USB plug via 150 Ω to SCART Pin 16, or use an OSSC / RGBtoHDMI.