What was found
ON CLIMBOUT, RT PACK LIGHT ILLUMINATED. QRH CHECKLIST ACCOMPLISHED & PACK RESET BUT FOR ONLY ABOUT 1 MINUTE. RAN CHECKLIST 1 MORE TIME & THIS CAUSED BLEED TRIP OFF LIGHT TO ILLUMINATE. RAN QRH & BLEED TRIP RESET BUT CAUSED PACK TO TRIP AGAIN. AT THAT POINT RAN QRH & ISOLATED RT PACK. DUCT PRESSURE NORMAL EXCEPT DURING BLEED TRIP OFF. FOUND BAD, R & R NR 2 ENGINE PRECOOLER CONTROL VALVE. FOUND BAD, R & R NR 2 ENGINE BLEED AIR REGULATOR. ALT PROCEDURE: POWER REMOVED FROM ACFT & THEN RE-INSTALLED W/OPS AND LEAK CHECK GOOD. R & R PRECOOLER CONTROL VALVE SENSOR