What was found
CLIMBING OUT OF 1000 FEET, WE HEARD A HISSING SOUND. WE THEN RECEIVED TWO COCKPIT NOTIFICATIONS: CABIN DOOR OPEN AND CHECK DOORS. WE ADVISED ATC THAT WE NEEDED TO HOLD SOMEWHERE TO TROUBLESHOOT. WE HELD AT 4000 FEET TO BURN OFF FUEL FOR ABOUT 20 TO 25 MINUTES. WE RETURNED AND LANDED WITHOUT ANY FURTHER ISSUES. ADJUSTED CABIN DOOR LATCH /LOCK SYSTEM PUSH RODS 1 & 2 TO RIG PRESSURE PREVENTION PANEL DOOR. FOUND INNER DOOR HANDLE STOP BOLT OUT OF ADJUSTMENT, ADJUSTED AS REQUIRED. FOUND FWD & AFT CABIN DOOR STOPS OUT OF ADJUSTMENT. ADJUSTED AS REQUIRED. PERFORMED REQUIRED RIG CHECKS, ALL MEASUREMENTS WITHIN SPECIFIED LIMITS. CLOSED ALL ACCESS. PERFORMED REQUIRED OPS CHECKS, OPS CHKD GOOD. PRESSURIZED ACFT WITH APU TO 4.5 PSI, VERIFIED NO SOUND COMING FROM CABIN DOOR PRESSURE PREVENTION PANEL OR DOOR SURROUND. WORK COMLPLETED IAW AMM 52-10-43, 52-10-05, 52-15-05, 52-10-35, 21-30-00, 32-00-00 AND 52-10-10.