As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 2 HF, IN FLIGHT WOULD TUNE & TRANSMIT FOR APPROXIMATELY 10 SECONDS THEN FAIL. WOULD DISPLAY FAIL ON BOTH THE ACTIVE & STANDBY SCREENS. IDENTICAL DISPLAYS ON CAPTAIN`S & FIRST OFFICER`S SIDES. ACFT GROUNDED. PERFORMED FIM 23-11, TASK 801, NO FAULTS FOUND. FAULT IS INTERMITTENT. REMOVED AND REPLACED NR 2 HF TRANSCEIVER IAW AMM 23-11-21-000-801, AND AMM 23-11-21-400-801. OPS CHECKED AND GROUND VERIFICATION WAS GOOD.