As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
IAD/BTV - FLT 6400 - DURING CLIMB AT 0810 HRS ON 5-16-97, MADE AN UNSCHEDULED LANDING DUE AIRCRAFT WOULD NOT PRESSURIZE IN AUTO OR MANUAL MODE. AIRCRAFT RETURNED TO GATE WITH NO FURTHER PROBLEMS. MAINTENANCE INSPECTED AND REMOVED AND REPLACED PRESSURE CONTROLLER. OPS CHECK OK. AIRCRAFT RELEASED AND APPROVED FOR RETURN TO SERVICE. (X)