As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
FLT#841, JFK-DUB. (ETOPS)'HF SELCAL ( HF 1 & HF 2 ) WOULD NOT WORK ON MULTIPLE FREQUENCIES WITH MULTIPLE ATC UNITS ( SELCAL (AMU) ); ACCOMPLISHED TEST NO FAULT REF AMM 23-11-00. SUCCESSFUL CALL ATTEMPTS ON TWO DIFFERENT FREQUENCY MDDR CLEAR MX-4 UPDATED.