As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DFW INFLIGHT T2427/25 FLIGHT ATTENDANT REPORTED SMOKE IN CABIN INCREASING IN INTENSITY AT MAX POWER, EPR 1.95 PACKS ON AND APU OFF. RETURNED TO DFW. LANDED WITHOUT INCIDENT. FOUND PRESSURE REGULATOR VALVE ON RT PACK INOPERATIVE. REPLACED PRESSURE REGULATOR VALVE ON RT PACK AND PERFORMED ENGINE RUNS AT 1.95 EPR WITH APU OFF AND BOTH PACKS ON. SYSTEM GROUND CHECKED NORMAL OPERATION.--CLOSED--