The logic board of the iMac (27-inch, Late 2009), model A1312, 2009, 27-inch, Core i5/i7. Known faults are being collected.
No guided tree is live for this board yet. The profile, the viewer and manual entry are there on the free plan, and the first sessions on it build the tree.
Checked on 2026-10-29 against 2 sources: corrected. Info said Mid 2010. Beetstech says 820-2733-A 'can only be used with the iMac 27-inch Late 2009 configured with Intel Core i5 or Core i7' (EMC 2374, iMac11,1), and Mac of All Trades sells it as the Late 2009 2.66 GHz i5 / 2.8 GHz i7 board (661-5429). The Mid 2010 27-inch board is 820-2901-A. Year changes from 2010 to 2009. Apple's identify page lists iMac10,1 for the Late 2009 27-inch order numbers; EveryMac and Beetstech give iMac11,1 for the Core i5/i7 configurations (MB953LL/A, MC507LL/A), which are the ones this board fits. The Core 2 Duo Late 2009 27-inch uses 820-2507. Consistency review: variant extended from '27-inch' to '27-inch, Core i5/i7' (taken from the corrections text above) so this row is distinguishable from 820-2507, the Core 2 Duo Late 2009 27-inch (iMac10,1). Revision A is a placeholder until Studio records the real revisions.
Open the board in NextProbe, answer the symptom questions and follow the lit point. The free plan includes three guided sessions a month. Your own boardview and schematic stay on your machine.