As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
GROUND CHECK OF THE NR 1 AND 2 HF SYSTEM, WAS OK. AIRBORNE NR 1 HF COULD NOT TRANSMIT. CAN HEAR SIDE TONE AND ATC BUT CANNOT TRANSMIT. ACFT GROUNDED. REMOVED AND REPLACED THE NR 1 HF TRANSCEIVER. OPS CHECKED GOOD, NO DEFFECTS NOTED IAW AMM 23-11-21-000-801 AND AMM 23-11-21-400-801.