As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SATCOM STATUS MESSAGE. CB PULLED AND COLLARED. LOW GAIN CHECKS OKAY. TROUBLESHOT REF FIM 23-15 TASK 843 , REPLACED SDU, CHECKED SOFTWARE (OPS AND ORT) ARE GOOD. GROUND TEST PASSED. MADE CALLS TO 777 ON BOTH CHANNELS--LOUD AND CLEAR. INSTALLATION TEST AT THE MCDU ALSO "OK".