Sony Test Disc Yeds-7.rar !link! Here

: Some specialized test discs include intentional data "interruptions" (simulated scratches) to see how well a player's error correction circuitry handles physical defects. Technical Specifications

For those unable to find a YEDS-7, the is often cited as a compatible successor for later model adjustments. Sony Test Disc Yeds-7.rar

: Calibrating the laser pickup's focus and tracking gain. : Some specialized test discs include intentional data