As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HF NR 1 INTERMITTENTLY CUTS OUT DURING TRANSMISSION, BOTH CAPTS AND F/O'S MIC. ACFT GROUNDED. AFTER NUMEROUS TEST DUPLICATED PROBLEM NR1 HF CUTS OUT ABOUT EVERY 7 TIMES. REPLACED NR1 HF TRANSCEIVER REF MM 23-11-21-000-801 OPS CHECK NORMAL IAW MM 23-11-21-400-801. GROUND VERIFICATION TEST GOOD.