What was found
REPEAT DISCREPANCY. WHILE IN CRUISE FLIGHT, THE FLIGHT CREW REPORTED AMBER PRI STAB TRIM FAIL MSG. THE ACFT WAS DIVERTED FOR MX. MX CREWS RESET THE HSTECU CB`S & THE FAULT CLEARED. OPERATIONAL CHECK OF THE HSTECU WAS PERFORMED & THE DISCREPANCY WAS DUPLICATED IN A WEIGHT OFF WHEEL CONFIGURATION. AN OPERATIONAL TEST OF THE PITCH TRIM SYS WAS PERFORMED WITH NO FAULTS FOUND. ELEC RIGGING OF THE PITCH TRIM SYS WAS ACCOMPLISHED & ANOTHER OPERATIONAL CHECK OF THE PITCH TRIM SYS WAS PERFORMED WITH NO FAULTS FOUND. THE FAULT MSG WAS NO LONGER PRESENT & THE ACFT WAS RETURNED TO SERVICE.