As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
WITH AUTO PRESSURIZATION ON MEL; CABIN PSI FLUCTUATES +-800 IN STBY. SELECTED AC FLUCTUATION INCREASED TO +-1500, SAME WHEN DC SELECTED. DIVERT TO MSP FOR REPAIR. REMOVED AND REPLACED CABIN PRESS CONTROLLER FOR AUTO PRESS MEL. REMOVED AND REPLACED CABIN PRESS CONTROL PANEL FOR STBY FLUCTUATIONS.