What was found
AIR TURNBACK, IN FLIGHT, THE LT MLG DOWN AND LOCKED LIGHT WOULD NOT GO OUT. R & R THE MAIN GEAR DIODE CARD NO HELP. SYSTEM FAILED THE GEAR POSITION TEST IN AMM. R & R LT MAIN GEAR GREEN DOWN LIGHT DIODE CARD PER FIM 32-61-00-815-819 BLOCK (22) AND MM 33-16-02-962-007.