As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
HF GOOD CARRIER ON GROUND. CHECKED NORMAL WHEN AIRBORNE HF BECAME FAINT AND THEN TOTALLY UNUSEABLE. TRANSMISSION NORMAL RECEIVE UNREADABLE. ON MULTIPLE FREQS AND BOTH RADIOS. BOTH UNUSEABLE R & R NR1 HF XCVR IAW AMM AND COUPLER. RERACKED AUDIO ACCY UNIT.CONTACTED SFO RADIO. SFO REPORTS LOUD AND CLEAR.