As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
UNABLE TO TRANSMIT OR RECEIVE ON HF2 WHEN TUNED TO A KNOWN FREQUENCY. ALSO NO SELCAL HF2. GROUNDED - YES. ACCOMPLISHED OPERATIONAL TEST B737-900 AMM TASK 23-11-00-710-801, #2 HF TRANSCEIVER OPS PASSED. HF #2 SYSTEM TEST WITH SFO ARINC ON FREQ 6.640 OPS NORMAL. GROUND VERIFICATION PASSED.