What was found
PUT GEAR HANDLE DOWN, NOTHING HAPPENED, NO LIGHTS, NO LANDING GEAR EXTENDED. EXECUTED MANUAL EXTENSION PROCEDURE, THREE GREEN LIGHTS, NO RED, LANDED UNEVENTFUL. PREVIOUS TO ABOVE, ELECTRICAL (SURGE). FAILED AUTOPILOT AND TECHS PANEL. RESET PANEL AND AUTOPILOT. RETURNED TO NORMAL OPS. AFTER LANDING, TURNED AIRCRAFT OVER TO MAINTENANCE TO TROUBLESHOOT PROBLEM. JACKED AIRCRAFT, APPLIED 20 PSI SHOP AIR TO POWER PACK, RAN GEAR FOR 5 FAULT FREE CYCLES. APPLIED ELECTRICAL LOAD ON AIRCRAFT TO SIMULATE FLIGHT CONDITIONS FOR 2 HOURS, RAN GEAR FOR 5 FAULT FREE CYCLES AND PLACED AIRCRAFT ON GROUND. RAN ENGINES TO CHECK BLEED AIR AT HYD POWER PACK. ALL FUNCTIONS OPERATIONAL, CHECKED GOOD.