A LARGE WDB ACFT BROUGHT TO THE GATE FROM MAINT AND LEFT UNPWRED WITH COCKPIT SWITCHES NOT IN NORMAL POS. ACFT WAS DISPATCHED AND DIVERTED DUE TO AUTOPLT AND AUTOTHROTTLE NOT ENGAGING.

Narrative

ACFT WAS BROUGHT TO GATE FOR DEP FROM COMPANY MAINT HANGAR. SEVERAL FLT CTL SWITCHES IN THE COCKPIT WERE OUT OF THEIR NORMAL POS; AND ACFT WAS UNPWRED WHILE IN MAINT. PREFLT CHKS; ENG START AND TAXI WERE ALL NORMAL. AS AUTOTHROTTLES WERE ARMED FOR TKOF; I FELT THE NORMAL 'BUMP' ON THE THRUST LEVERS AS THE SERVOS WERE ARMED. THE AUTOTHROTTLES ENGAGED AND ALL INDICATIONS WERE NORMAL ON THE TKOF ROLL AND INITIAL CLB. AT SOME POINT IN THE CLB AND DURING FLAP AND SLAT RETRACTION; THE AUTOTHROTTLES CEASED OPERATING. ALSO IN THIS SAME PERIOD OF TIME; A 'MISC' CUE LIGHT AND ADVISORY MESSAGE APPEARED ON THE EICAS. WHEN THE MISC PAGE WAS SELECTED; A 'NO AUTOLAND' MESSAGE WAS IN VIEW. AT 10000 FT LEVELOFF; THE FO (PF) CALLED FOR AUTOPLT ON. THE AUTOPLT AND AUTOTHROTTLES WERE INOP AND WOULD NOT ENGAGED. A RADIO PATCH TO MAINT LED US THROUGH A SERIES OF CIRCUIT BREAKER RESETS AND ATTEMPTS TO RESTORE PWR TO THE INOP COMPONENTS. WHEN ALL ATTEMPTS FAILED WE WERE INSTRUCTED TO RETURN TO ZZZ AND MAKE AN OVERWT LNDG TO AVOID FUEL DUMPING OF 100000 LBS. LNDG WAS NORMAL AND TAXI IN NORMAL. I WAS ADVISED BY MAINT CTL AT A LATER TIME THAT THE FLT CTL COMPUTERS HAD FAILED THEIR PWR-UP TESTS (PROBABLY BECAUSE THE FLT CTL SWITCHES WERE IN THE OFF POS) DURING INITIAL PWR INSTALLATION. ALL OF THIS WAS 'MASKED' TO THE FLC UNTIL THE ACFT BECAME AIRBORNE. ALL OUR COCKPIT INDICATIONS WERE NORMAL UNTIL THE ACFT WAS FLYING. MY COMPANY IS LOOKING AT THEIR IN-SVC CHKS PRIOR TO PUTTING AN ACFT BACK INTO SVC.