Power Supply Bracket – Power Mac G3 (B&W), G4 Graphite $5.00 Stamped 805-2178 Power Supply Bracket - Power Mac G3 (B&W), G4 Graphite quantity Add to cart Add to Quote Continue Shopping Category: Case & Internal Parts (G3 to G5) Tags: bracket, power supply Description Power Supply Bracket and screws. Apple number 922-3766, 805-2178. For Power Mac G3 (Blue & White) and all Power Mac G4 Graphite models – PCI, AGP, Gigabit, Digital.