As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT HAD AN AIR TURNBACK TO SEA. DUE TO EICAS MSG TCAS DISPLAYED. REPLACED UPPER TACS ANTENNA PER MM 34-45-02. FOUND ANTENNA CABLE SHORTED TO SHIELDING, RESET CONNECTOR D6081P CHECKED CENTER CONNECTOR TO SHIELD WITH MEGGED AT 100 OHMS. NO SHORTS NOTED PER WDM 34-45-11 AND TACS OPS CHECK OK FOR SERVICE PER MM 34-45-00.