Power Transformer Wiring Colors Mike at Forwater.com http://www.Fourwater.com 24 Feb 2019 (revised 30 Dec 2023) Primary: Black = Primary Common Black+Yellow = Primary Voltage Tap Black or Black+Red = Primary Main Secondaries: Rectifier Filament Yellow Yellow+Blue Yellow Rectifier Plate Red Red+Yellow Red Tube Filament #1 Green Green+Yellow Green Tube Filament #2 Brown Brown+Yellow Brown Tube Filament #3 Slate Slate+Yellow Slate Audio Transformer Wiring Colors Primary: Plate : Blue or Brown (start) B+ : Red Plate : Blue Secondary: Grid : Green or Yellow (start) Return : Black Grid : Green IF Transformer Wiring Colors Plate : Blue B+ : Red Grid : Green (or diode lead) Return : Black Diode2 : Green+Black (second diode for FW circuits)