What was found
DEN - ABORTED TAKEOFF - FLT 0640 - DURING TAKEOFF ROLL AT DEN EN ROUTE FOR PHX, A LOUD "BANG" CAME FROM THE NR 1 ENGINE, REJECTED TAKEOFF, SUSPECT COMPRESSOR STALL. MAINTENANCE PERFORMED A BORESCOPE INSPECTION IAW T/C I5M72008, NO DAMAGE NOTED. REMOVED AND REPLACED THE PRESSURE RATIO BLEED CONTROL IAW T/C R5M75002. LUBRICATED BLEED VALVES IAW BMM 75-31-0, AND PERFORMED A HIGH POWER ENGINE RUN, SYSTEM OPERATES NORMALLY. VENDOR FUNCTIONAL TEST OF PRESSURE RATIO BLEED CONTROL S/N 6159383 COULD NOT CONFIRM REASON FOR REMOVAL, NO FAULT FOUND. TESTED IAW CMM 75-31-01 AND RETURNED TO SERVICE.