What was found
AFTER TAKEOFF KGCK, SELECTED GEAR UP & HANDLE WOULD NOT MOVE. PRESSED DOWN LOCK REL BUTTON, HANDLE WENT UP BUT NLG SHOWED IN TRANSIT & WOULD NOT RETRACT. ABOUT THE SAME TIME GOT LG AIR & GND POST EICAS. SELECTED LG DOWN GEAR EXTENDED & GOT 3 GREEN INDICATION, DIVERTED TO AMA. ABOUT 20 MINUTES INTO FLT LA AIR & GND FAIL EICAS WENT AWAY. UNABLE TO DUPLICATE, SUSPECT ICE ON NLG PREVENTED FULL EXTENSION. VERIFIED WOW SYS, OPERATIONS CHECKED OK IAW AMM CH 32-63-00. VERIFIED NLG STRUT FULLY EXTENDS & NWS CTR CAM ENGAGES. VERIFIED LANDING GEAR EXTENSION & RETRACTION, OPERATIONS CHECKED OK IAW AMM CH 32-30-00 & RII 146777.