What was found
DURING CLIMB OUT AFTER TAKEOFF, WITH 1.2 NOSE DOWN STAB TRIM, EXPERIENCED SIGNIFICANT NOSE UP CONTROL PRESSURE. REQUIRING PILOT NOSE DOWN YOKE PRESSURE. LEVELED OFF AT 10,000 FT & SLOWED ACFT UNTIL NO PITCH CONTROL PRESSURES FELT. PRIMARY TRIM UNRESPONSIVE. COMPLETED JAMMED STAB TRIM SYS CHECKLIST. REMOVED MACH TRIM ACTUATOR LINKAGE AND REPLACED SHEARED RIVETS, REINSTALLED MACH TRIM ACTUATOR. REMOVED AND REPLACED DAMAGED MACH TRIM CONTROL CABLES. RE-ROUTED MACH TRIM ELECTRICAL HARNESS DUE TO BINDING. PERFORMED ELEVATOR CONTROL CABLE TENSION AND ADJUSTMENT. PERFORMED ELEVATOR TRIM TAB CABLE TENSIONS AND RIGGING.