This comprehensive service manual provides detailed technical information and instructions for servicing Yamaha's RX-V420, RX-V420RDS, HTR-5440, and HTR-5440RDS audio/video receivers. The manual covers all applicable years of production for these models and includes detailed schematics, circuit diagrams, component identification, troubleshooting guides, repair procedures, and parts lists. Whether you're a seasoned technician or a DIY enthusiast, this service manual offers the necessary tools to diagnose and repair any issues that may arise with your Yamaha receiver.