What was found
AT FL230 CABIN ALT SPIKED TO 5,900FT. AT 3,700 FPM. AT 10000FT, CABIN ALT DECREASED TO 900FT AT 300 FPM. FROM 10000 FEET TO LANDING, PSI'N ACTED NORMALLY. PRESSURIZATION WAS IN AUTO MODE FOR THE ENTIRE EVENT. BOTH PACKS OPERATED NORMALLY THE ENTIRE FLIGHT. NO CABIN ALT WARNING OR AURAL MESSAGES. ***AIRCRAFT REMOVED FROM SERVICE*** R&R #1 CABIN PRES CONTROLLER PER CRJ 200 AMM 21-31-16 PRES AC PER CRJ 200 AMM 21-32-00 OPS CK GOOD P/N: 2119768-8, S/N OFF: 112-C1551, S/N ON: 123-C1876 ARW