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
Connector Orientation
Viewed looking at the rear of the Sinclair QL (Left to Right)
Left Blade
15.6 V AC RMS @ 200 mA (feeds internal +12V & -12V regulators)
Center Blade
0 V Common Ground Return (shared by +9V DC and 15.6V AC)
Right Blade
+9.0 V DC Unregulated (~11–13V unloaded @ 1.8 A — feeds internal 7805)
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| Left Blade (Rear View) | 15.6V AC | Pwr | 15.6 V AC Transformer Output (200 mA — powers internal 7812 & 7912) | Yellow / White |
| Center Blade (Rear View) | GND / COMMON | GND | 0 V Common Return for both 9V DC and 15.6V AC | Black |
| Right Blade (Rear View) | +9V DC UNREG | Pwr | +9.0 V DC Unregulated Input (1.8 A — powers internal 7805) | Red |
Eliminating the Scorching Internal QL 7805 Heatsink
Just like the ZX Spectrum +2/+3 and TI-99/4A, the Sinclair QL power brick (PSU 9V DC / 15.6V AC) performs only half the regulation externally: it outputs unregulated ~9–11 V DC (1.8 A) and 15.6 V AC (200 mA) over a 3-slot flat blade connector, while the actual +5 V (7805), +12 V (7812), and -12 V (7912) regulators sit inside the QL.
- Drop-In 5V Buck Converter Upgrade: Replace the internal TO-220 7805 regulator bolted to the long aluminium bar along the back of the QL with a 5 V 2 A / 3 A switching DC-DC buck module (Recom R-78B5.0-2.0 or ezPSU-QL) to cut internal case temperatures by 15 °C.