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.
Used in Retro Machine Hubs
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Connector Specifications
CoCo 3 J1 Header
2×5 (10-Pin) 2.54mm IDC Header on bottom of CoCo 3 case
CoCo 3 Signals
0.7 Vpp Analog Red (Pin 3), Green (Pin 4), Blue (Pin 5) + HSYNC (8) & VSYNC (9)
PET J7 Header
7-Pin 0.156" (3.96mm) Inline Molex Header on rear-right of PET PCB
PET J7 Signals
5 V TTL Video (Pin 1), Vertical Drive (Pin 3), Horizontal Drive (Pin 5)
Full Pin Assignment & Wiring Reference
| Pin | Signal Name | Direction | Electrical Spec / Role | Wire Colour / SCART / Adapter Target |
|---|---|---|---|---|
| CoCo J1 Pin 1 & 2 | GND (0 V) | GND | CoCo 3 Video & Audio Return Ground | SCART Pins 4, 5, 9, 13, 17, 18, 21 |
| CoCo J1 Pin 3 | ANALOG RED | Out | CoCo 3 0.7 Vpp Analog Red Output | SCART Pin 15 (Red) |
| CoCo J1 Pin 4 | ANALOG GREEN | Out | CoCo 3 0.7 Vpp Analog Green Output | SCART Pin 11 (Green) |
| CoCo J1 Pin 5 | ANALOG BLUE | Out | CoCo 3 0.7 Vpp Analog Blue Output | SCART Pin 7 (Blue) |
| CoCo J1 Pin 6 | AUDIO OUT | Out | CoCo 3 Mono Audio Output | SCART Pins 2 & 6 (Audio L+R) |
| CoCo J1 Pin 8 & 9 | HSYNC (8) & VSYNC (9) | Out | CoCo 3 TTL Syncs (Or tap rear Composite RCA jack for CSYNC!) | SCART Pin 20 (Sync In) |
| PET J7 Pin 1 & 2 | TTL VIDEO (1) & GND (2) | Out | PET 5 V TTL Pixel Stream (Pin 1) & Video Return GND (Pin 2) | RGBtoHDMI Lum/Video In |
| PET J7 Pin 3 & 4 | VERT DRIVE (3) & GND (4) | Out | PET 5 V TTL Vertical Sync (50/60 Hz) & Return GND | RGBtoHDMI VSYNC In |
| PET J7 Pin 5 & 7 | HORIZ DRIVE (5) & GND (7) | Out | PET 5 V TTL Horizontal Drive (15.6kHz or 20kHz) & Return GND (Pin 6=Key) | RGBtoHDMI HSYNC In |
CoCo 3 Rear Composite RCA CSYNC Trick & PET External Monitor Testing
On the underside of every Tandy Color Computer 3 sits a recessed 2x5 (10-pin, 0.1" pitch) IDC box header (J1) originally intended for the Tandy CM-8 RGB monitor; it outputs 0.7 Vpp 64-colour Analog RGB + TTL Sync. Meanwhile, inside every Commodore PET (2001, 3032, 4032, 8032) sits the 7-pin inline J7 header carrying separate TTL Video, Vertical Drive, and Horizontal Drive to the internal monochrome CRT.
- Easiest CoCo 3 RGB SCART Cable Trick: Instead of building an H+V sync combiner circuit for J1 Pins 8 and 9, simply plug an RCA lead into the CoCo 3's rear Yellow Composite Video RCA jack and wire it into SCART Pin 20 (Sync In) alongside J1 Pins 3, 4, 5 (Red, Green, Blue) and Pin 10 (+5V via 180 Ω to SCART Pin 16)!
- Testing a Commodore PET Motherboard on the Bench Without the Heavy CRT: Connect PET J7 Pin 1 (Video), Pin 3 (Vert Drive), Pin 5 (Horiz Drive), and Pin 2/4/7 (GND) to an RGBtoHDMI TTL board to view both 40-column (15.6 kHz) and 80-column (20 kHz) PET video on any HDMI monitor!