As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
DURING PREPARATION FOR NR 2 ENG COOLING BAROMETRIC SWITCH OPC FOUND DAMAGED SCREW AT NACELLE ZONE VENT SHUTOFF VALVE. AFTER INVESTIGATION FOUND THAT THIS SCREW WAS TOUCHING THE FEEDER CABLES. TWO CABLE GOT DAMAGED AND PRODUCED ARCING TO THE VALVE HOUSING SCREW. THIS DAMAGE OCCURED DUE TO WRONG FEEDER CABLE CLAMP INSTALLATION. THE TWO FIRST CLAMPS WERE INSTALLED 180 DEGREE IN THE WRONG DIRECTION WHICH LEAD TO NOT ENOUGH CLEARANCE TO THE VALVE BODY.