As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HF#1 TRANSMITTER INOP (BOTH SEATS). WE CAN HEAR HF #1 AND GET SELCAL ON HF #1, BUT NO TRANSMIT CAPABILITY. GROUNDED - YES. VERIFIED DISCREP. REF B737-900 AMM 23-11-21, REMOVED/REPLACED HF-1 TRANSCEIVER, FOUND TO BE INOP - BAD FROM STOCK. REINSTALLED ORIGINAL HF-1 TRANSCEIVER REF SAME AMM AND PERFORMED HF SYSTEM TEST W/GOOD COMMUNICATION WITH SAN FRAN ARINC. GROUND VERIFICATION TEST GOOD.