As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PRE-FLIGHT 'CONTROL FREEDOM CHECK', THE FLIGHT CONTROLS BECAME JAMMED IN THE NOSE DOWN POSITION! THE RADIO RACK COOLING PLENUM HAD FALLEN INTO THE YOKE PATH. UPON FURTHER INVESTIGATION, ONLY ONE OF THE FOUR RETAINING CLAMPS/SPRINGS WAS FOUND AND IT WAS NOT ATTACHED PROPERLY. SUBMITTER STATED INSPECTION AND ADHERANCE TO CESSNA'S AVIONICS INSTALLATION MANUAL IS RECOMMENDED.