Panel wiring via pin headers

MIDI IN Header (3‑pin)

• Pin 1 → DIN Pin 4
• Pin 2 → DIN Pin 5
• Pin 3 → Ground (DIN Pin 2)

THRU Headers (4 × 3‑pin)

Each THRU jack uses:

• Pin 1 → +5 V (through 220 Ω) → DIN Pin 4
• Pin 2 → 74HC14 output (through 220 Ω) → DIN Pin 5
• Pin 3 → Ground → DIN Pin 2

Power Switch Header (2‑pin)

• Pin 1 → DC jack +V
• Pin 2 → 7805 VIN

IN LED Header (2‑pin)

• Pin 1 → LED anode (via 1 kΩ)
• Pin 2 → Ground

MatrixPortal Header (3‑pin)

• GND
• RX (from MPS6514 NPN collector)
• +5 V