What was found
EN ROUTE NR 1 CONSTANT SPEED DRIVE (CSD) LOW OIL PRESSURE LIGHT ILLUMINATED & NR 1 GENERATOR DROPPED OFF LINE, APU ALREADY ON MEL, DIVERTED INTO RNO FOR REPAIR. MX R & R NR 1 CSD / GENERATOR IAW T/C R5M24007, AND CSD OIL COOLER AND IN-LINE FILTER IAW T/C R5M24008, OPERATIONAL CHECK OF NR 1 CSD / GENERATOR GOOD. TEAR DOWN REPORT OF CSD CONFIRMS FAILURE. WHEN CSD OPENED, FOUND UNIT FULL OF METAL & SEVERAL COMPONENTS SEIZED/DAMAGED. TEAR DOWN OF CSD SHOWS CARRIER SHAFT BORES CLOGGED WITH DEBRIS CAUSING A LACK OF LUBE TO GEARS WITH ASSOCIATED LOW OIL PRESSURE LIGHT ILLUMINATING. THIS CAUSED PLANET GEAR & SHOULDER SHAFT TO SEIZE TOGETHER, DROPPING GENERATOR OFF LINE. UNIT WAS OVERHAULED AND RE-TESTED IAW CMM.