As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
CREW REPORTED THE STAB TRIM & MACH TRIM WILL NOT ENGAGE ON CLIMBOUT. CREW ELECTED TO RETURN TO LEX AND LANDED WITHOUT INCIDENT. MAINTENANCE CYCLED THE HSTCU CIRCUIT BREAKERS, PERFORMED A MEMORY RESET AND PERFORMED AN OPS CHECK IN ACCORDANCE WITH THE AIRCRAFT MAINTENANCE MANUAL. BITE AND OPS CHECKS BOTH WERE GOOD AT THIS TIME. AIRCRAFT WAS RELEASED FOR SERVICE.