As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HF#1 TRANSMITS BUT RECEPTION IS COMPLETELY GARBLED AND ILLEGIBLE/ NOT UNDERSTANDABLE. GROUNDED - YES. ACCOMPLISHED OPS TEST WITH NO FAULTS FOUND REF B737-800 AMM 23-11-00. ACCOMPLISHED HF COMM BITE REF B737-800 FIM 23-11 TASK 801 WITH NO FAULTS FOUND. GROUND VERIFICATION TEST SUCCESSFUL.