As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
ATTEMPTED TEST CALL ON SAT 1 & SAT 2. WE COULD HEAR DISPATCH BUT THEY COULD NOT HEAR US. ACFT GROUNDED. REMOVED AND INSTALLED A NEW SATCOM TRANSFER PANEL IAW AMM 23-15-00. PERFORMED SYSTEM TEST IAW AMM 23-15-00-730-801, SYSTEM CHECKED NORMAL. PERFORMED HF OPS TEST IAW AMM 23-11-00, SYSTEM CHECKED NORMAL.