What was found
DIVERSION/DECLARED EMERGENCY. ALTITUDE WARNING HORN AT CRUISE FL 390 CABIN ALT CLIMBED TO 14K PRESSURIZATION VERY ERRATIC AND SLOW TO COME BACK DOWN BELOW 10K. NO OR VERY LITTLE CONTROL IN AUTO. MANUAL PRESS WITH NR 1 BLEED CLOSED, PRESS RESPONDED NORMALLY. REMOVED AND REPLACED NR 1 ENGINE HIGH STAGE REGULATOR, BLEED AIR REGULATOR, PRSOV, AND 35 DEGREE CONTROLLER PER MM.