As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER TAKEOFF NOTICED LEFT DUCT PRESS GAUGE CLOSE TO ZERO. FLIGHT DECK FELT VERY WARM, NO MASTER CAUTION OR FAILURE LIGHTS. AIR RETURN & TROUBLE SHOT ENG BLD REF 36-10-00. FOUND LINE TO PRSOV BROKEN. REPLACED SAME NR 1 ENG BLD. OPERATIONS CHECKED GOOD. ACFT OK TO CONTINUE.