As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
NR 1 HF TRANSMITTER IS INTERMITTENT INITIALLY IT WAS WORKING OK AND THEN COULD NOT BE HEARD BY SFO RADIO OR OTHER AIRCRAFT. IT RECEIVED TRANSMISSIONS AND SELCAL NORMALLY. DURING THE TIME NR 1 HF COULD NOT BE HEARD NR 2 HF OPERATED NORMALLY. GROUNDED - YES. REMOVED AND REPLACED NR 1 HF TRANSCEIVER REF AMM 23-11-21 GROUND VERIFICATION NORMAL.