What was found
WINDSHIELD HEAT INOP L AMBER CAS MESSAGE ILLUMINATED, FOLLOWED BY (5 MIN) BY FIRE DETECT L, FOLLOWED BY (5 MIN) HYD VOL LOW FOLLOWED BY HYD PRESS LOW R L . FOLLOWED CHECKLIST PROCEDURES FOR EACH MESSAGE AS THEY ILLUMINATED. BLEW DOWN LANDING GEAR PER CHECKLIST AND LANDED UNEVENTFULLY. REMOVED AC GENERATOR OFF P/N: 9914443-1, OFF S/N: 965 AND FOUND THE SHAFT SHEARED OFF. INSTALLED OVERHAULED AC GENERATOR PN: 9914443-1, SN: 603 ON LEFT ENGINE. OPS CHECKS GOOD. IAW CE-680A AMM 24-20-05.