As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HF 1 RECEIVED TRANSMISSIONS THAT WERE SO DISTORTED & GARBLED THEY WERE UNABLE TO UNDERSTAND. SAME ON COM 1 & 2. HF 2 WORKS FINE. ACFT GROUNDED. IAW AMM 23-11-21 REMOVED DEFECTIVE NR 1 HF TRANSCEIVER AND INSTALLED SERVICEABLE HF TRANSCEIVER IN THE NR 1 POSITION IAW AMM 23-11-21. GROUND VERIFICATION CHECK SUCCESSFUL. ACFT OK FOR SERVICE.