What was found
IN FLIGHT NR 1 HF RADIO DISPLAYED "FAIL" BOTH CONTROL HEAD WINDOWS DURING ATTEMPTED TX NO SIDE TONE AND A NON COUPLER "BEEP" ON EACH SUBSEQUENT ATTEMPTS. SWITCHED NR 1 HF TO DATA INTERMITTENT DATA RX/TX FOR ENTIRE FLT. HFDR MAINT PAGES SHOWED NORMAL/NORMAL HFDR/CPLR. UNABLE TO DUPLICATE DEFECT. ACCOMPLISHED SEVERAL GOOD COMMUNICATIONS WITH SFO USING NR 1 HF FREQ 5.547 GOOD SIDE TONE WHILE TUNING AND NO FAIL DISPLAYED ON CONTROL HEAD. NR 1 HF GROUND VERIFICATION TEST PASSED REF MM 23 11 00. NR 1 HF DATA TEST PASSED REF MM 23 27 00. NO HISTORY PAST 90 DAYS SEAMC NOTIFIED.