As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO TRANSMIT ON HF1 RADIO. ATTEMPTED CAPT + FO SIDE. HF1 RADIO DOES RECEIVE. HF2 RADIO TRANSMIT AND RECEIVE FOR BOTH CAPT AND FO. GROUNDED - YES. RESET BREAKERS AND CONDUCTED BITE TEST OF #1, #2 HF TRANSCEIVERS WITH NO FAULTS PER B737-800 AMM 23-11-00-710-801.