What was found
AIR TURNBACK FLIGHT 7757 AT MAF: WHEN CREW SELECTED GEAR UP, THE MAIN GEAR WOULD NOT RETRACT AND RECEIVED A LOW PRESSURE LIGHT ON THE GREEN HYDRAULIC SYSTEM. THE NR 2 ACW SYSTEM FAILED. CREW ELECTED TO RETURN TO MAF. INSPECTED C/B AND FOUND THE GREEN SYSTEM HYD PUMP C/B POPPED. RESET C/B RAN ENGINES AND LOW PRESSURE LIGHT WAS EXTINGUISHED ON THE GREEN SYSTEM, PRESSURE WAS 3000 PSI. TAXI ACFT AND CHECK BRAKES FROM THE PILOTS, F/OS, AND HAND/PARKING BREAK. SYSTEM CHECK GOOD AND WORKED NORMALLY. AIRCRAFT WAS RETURNED TO SERVICE.