What was found
PERFORMED BLEED OFF TAKEOFF IN HNL. UPON CONFIGURING BLEEDS; #1 BLEED VALVE DID NOT OPEN. OPENED ISO VALVE TO CONFIRM #1 PACK OPERATION. L DUCT PRESS SHOWED ZERO W/PACK & BLEED SW ON W/ISO VALVE IN AUTO. ATTEMPTED NUMEROUS RECYCLES OF SWITCHES. CONTACTED MX CTRL AND AS WE WERE CLIMBING THRU 12000' & WAITING FOR MX; VALVE OPENED & OPS NORMAL FOR REMAINDER OF FLIGHT. MX ADVISED TO CONTINUE 7 WRITE UP EVENT IN PDX GROUNDED - YES. PERFORMED HEALTH CHECK OF THE #1 ENGINE PRSOV AND FOUND PRSOV WITH POOR RESPONSE USING WRENCH ON MANUAL OVERRIDE. REMOVED & REPLACED THE #1 ENGINE PRSOV REF B737-800 AMM 36-11-04. OPS CK LEAK CK GOOD, NO OTHER DEFECTS NOTED. NO OTHER HISTORY WITHIN 30 DAYS.