As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING CLIMB THROUGH 35000 FT, MASTER WARNING AND CABIN ALTITUDE ALARM WERE PRESENTED; EMERGENCY DESCENT WAS STARTED TO 21000 FT. CHECK LIST WAS PERFORMED. DURING MANUAL TEST PROCEDURE IAW AMM 21-31-00 PAGE 507 WAS FOUND THAT OUTFLOW VALVE WAS NOT WORKING WHEN SELECTOR IS IN MANUAL CLIMB AND DESCEND. OUTFLOW VALVE WAS REPLACED IAW AMM 21-31-03 PAGE 201 WITH SATISFACTORY RESULTS.