As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING TAXI OUT, SUBSEQUENT TO THRUST REVERSER AND ANTI-ICE OPS CHECKS, THRUST REVERSER ON RT ENGINE FAILED TO DEPLOY WHEN COMMANDED. RETURNED TO HANGAR AND FOUND KNOB LOCK JAMMED. MANUALLY CRANKED T/R TOWARDS OPEN/DEPLOYED DIRECTION AND LOCK FREED UP. OPS CHECKED, SYS OK.