Power supply (205W) for Apple Apple iMac 21.5 inch A1311 (Late 2009 – Mid 2011) Part Number : 661-5299 614-0445 OT8043 ADP-200DF, EMC 2308, 2389, 2428, 2496 - WIT Computers
MC508LL/A Model A1311 (EMC 2389) Fuente de Alimentacion
How to Upgrade iMac RAM (21.5" and 27" Aluminum): EveryMac.com