What was found
WHEN PREPARING FOR TAKEOFF AT DFW EN ROUTE FOR PHX WHEN THROTTLES ADVANCED RECEIVED COMPRESSOR VANE FAULT. MAINTENANCE REMOVED AND REPLACED THE PRESSURE RATIO BLEED CONTROL IAW T/C R5M75002, AND LUBRICATED THE 13TH STAGE BLEED VALVE IAW BMM 75-31-0, PG. 602. RAN ENGINES AT TAKEOFF POWER AND PERFORMED BLEED SCHEDULE; SYSTEM CHECK WAS GOOD. VENDOR BENCH TEST OF PRESSURE RATIO BLEED CONTROL S/N 0101 CONFIRMED FAILURE OF UNIT. REPLACED LEVER (P/N 393909), CONNECTOR, VENT, PIN, AND 2 EACH PINS. UNIT TESTED AND RETURNED TO SERVICE IAW CMM 75-31-01, REV. 16.