As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WHILE ON CLIMBOUT AIRCRAFT CABIN PRESSURIZATION STARTED MAKING FULL SCALE FLUCTUATIONS OR HAD NO INDICATION AT ALL. PILOT REPORTED , ALSO THAT IT SEEMED TO HAVE NO POWER. CREW ELECTED TO RETURN TO DEPARTURE AIRPORT AND A UNEVENTFUL LANDING WAS ACCOMPLISHED. MX DISCOVERED A FAULTY CABIN PRESSURE INDICATOR, PART WAS REPLACED AND OPS CHECKED NORMAL.