As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT PREFLIGHT, THE PILOT NOTICED THAT THE SPEED BRAKES DID NOT CLOSE COMPLETELY. MAINT WAS CALLED AND AFTER SOME OPERATIONAL CHECKS AND A VISUAL INSPECTION OF THE CONTROL SYS AT THE LT MAIN GEAR WHEEL WELL A STONE WAS FOUND AT A CONTROL CABLE PULLEY AND THE STONE WOULD NOT ALLOW THE CABLE TO CLOSE THE SPEED BRAKES ALL THE WAY. STONE LOGED IN PULLEY. (K)