What was found
TOTAL LOSS OF CABIN PRESSURE AT FL 390. PREVIOUS HISTORY OF CABIN PRESSURE PROBLEMS. RT ENGINE BLEED & ASSOC EICAS LIGHT ILLUMINATED. FOLLOWED APPROPRIATE QRH. PNEU DUCT PRESSURE, RT SIDE, SLOWLY BUT STEADILY DECREASED & THEN EICAS ILLUMINATED. THEN SUBSEQUENTLY THE LEFT ENGINE BLEED LIGHT ILLUMINATED WITH A CORRESPONDING PNEU DUCT DECREASE. USED FIM 36-10/811. FOUND NO DISCREPANCIES. DUE TO HISTORY GOING TO REPLACE BOTH ENGINE FAMV'S AT THIS TIME THE RIGHT VALVE HAS BEEN REMOVED AND REPLACED PER MM 36-11-16-4. OPS GOOD. REMOVED AND REPLACED LEFT FAMV PER MM 36-11-16-4. RAN BOTH ENGINES AND COULD FIND NO DISCREPANCIES. ACFT IS OK FOR SERVICE.