As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AFTER PRESSURIZATION PROBLEM, PILOT PULLED BOTH SHUT-OFF HANDLES CONTROLLING VALVES AT FIREWALL. AFTER FIXING PROBLEM AT OUTFLOW AND SAFETY VALVES, ATTEMPTED TO RESET HANDLES IN COCKPIT CAUSING INNER CONTROL TO PUSH OUT OF HOUSINGS. THESE CONTROLS ARE NORMALLY LEFT IN ONE POSITION ALL THE TIME. SUBMITTER SUGGESTS WORKING THESE CONTROLS OCCASIONALLY TO KEEP THEM FREE.