What was found
AFTER POWER TRANSFER, SATCOM LOCKUP OCCURRED. FOLLOWED QRH PROCEDURE. SAT RETURNED TO NORMAL OPS AFTER NEXT POWER TRANSFER LOCKUP OCCURRED AGAIN. GROUNDED - YES. REF L/P 60589552 -- ACCOMPLISHED SDU SOFTWARE LOAD REF B737-900 AMM 23-15-00-470-801 3 FILES LOADED "CONFIG CRC" AC391300 VERIFIED, CIM OPTIONS SAVED. VERIFIED AOC DIR NUMBERS PRESENT. SATCOM SYSTEM TEST PASS REF AMM 23-15-00-730-801 CALLS MADE AND RECEIVED WITH DISPATCHED ALONG WITH TWO STAGE CALL TO AIRCRAFT.