What was found
(CAN) BOTH STABILIZER TRIM CHANNEL NR 1 AND 2 AND MACH TRIM DISENGAGED UPON LANDING.EVENT: WOULD NOT REST (LANDING WAS UNEVENTFUL, NO EMERGENCY DECLARATION). ON CLIMB OUT THROUGH 2000 FEET, THE STAB / MACH TRIM CAUTION MESSAGE APPEARED. RESET SYSTEM TWICE. RETURNED TO DEPARTURE AIRPORT, LANDING WAS UNEVENTFUL. REPLACED THE MACH TRIM / STAB CONTROL PANEL, REPLACED THE STABILIZER ACTUATOR AND MCU, A/C RETURNED TO SERVICE