Logic Board – Power Mac G4 QuickSilver Apple Rescue of Denver » Products Page » G3 to G5 » Cards - Boards - Power Supplies (G3 to G5) » Logic Board - Power Mac G4 QuickSilver For the all QuickSilver models. Logic Board for Power Mac G4 QuickSilver models. This is a Rev 1 board - Apple 661-2503, 820-1276,820-1276-A. Rev 1 and 2 are interchangeable both ways, the Rev 2 numbers are 661-2606, 820-1342,820-1342-B. Product in stock Price: $50.00 Updating cart... Updating...