As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 HF WAS UNREADABLE ON ALL ASSIGNED FREQUENCIES THROUGHOUT THE FLIGHT. NR 2 HF WORKED 5X5 GOOD ON ALL FREQUENCIES. ACFT GROUNDED. CONFIRMED FAULT WITH NR 1 HF, REF FIM 23-11-806. SWAPPED 1 HF AND NR 2 HF COUPLERS FOR TROUBLESHOOTING, REF MM 23-11-61. FAULT CONFIRMED. SWAPPED COUPLERS NR 1 & NR 2 BACK TO ORIGINAL POSITION. REPLACED NR1 HF COUPLER IAW AMM 23-11-61. NR 1 HF SYS OPERATES NORMALLY.