As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AT TIMES WHILE IN ETOPS AIRSPACE, HF 1 RADIO WOULD NOT BREAK SQUELCH WITH ANY PUSH-TO-TALK BUTTON. OTHER TIMES IT WORKED FINE AND WE WERE ABLE TO COMMUNICATE. GROUNDED - YES. VERIFIED FAULT, R&R 1 HF TRANSCEIVER IAW AMM 23-11-21-400-801. GROUND OPS CHECK NORMAL PER SYSTEM TEST. REF AMM 23-11-00-730-801. AIRCRAFT OK FOR SERVICE.