As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO TRANSMIT ON HF 2. GROUNDED - YES. ACCOMPLISHED HF COMMUNICATION SYS BITE PROCEDURE PER B737-800 FIM 23-11 TASK 801 BITE TEST GOOD. FOR T/S SWAPPED TRANSCEIVER #1 TO #2 SLOT B737-800 AMM 23-11-21-400-801. NO HELP. SUGGESTED COUPLER CHANGE. RETURNED HF RT'S TO ORIGINAL POSITIONS, REF AMM 23-11-21. REPLACED HF #2 COUPLER REF AMM 23-11-61 OPS CHECK OK.