What was found
AIR TURN BACK, UNABLE TO RECEIVE HF RADIO TRANSMISSIONS ON EVERY HF FREQ WE COULD FIND. CONTACTED DISPATCH, ATB REQUIRED. PRIOR TO DEPT HF CHECK WITH OTHER AIRPLANE SUCCESSFUL ON BOTH HF RADIOS. HF RIGHT. T/S RIGHT HF SYSTEM FOUND SQUELCH ON PREVENTING RECEIVE AUDIO, OPENED SQUELCH AND RECEIVE AUDIO CAME BACK, VERIFIED SIDETONE/MONITOR FUNCTION IS PRESENT, ALSO VERIFIED TUNING FUNCTION, ALL CHECKS GOOD, MADE CONTACT FROM STATION IN RHODE ISLAND USING SINGLE SIDE BAND(USB) AND GOT A 5/5 SIGNAL REPORT, ALSO RECEIVED THEM AT A 5/5 SIGNAL, RIGHT HF SYSTEM TEST OK REF B767 AMM 23-11-03, THIS CLEARS MEL, PLACARD REMOVED.