Lost a screw?
Logic Board (motherboard) screw. Power Supply Screw. There are only three screws attaching components to the case. Power supply uses one, logic board uses one plus the captive screw in the support column. Fits all Centris / Quadra 610 / 660 models, Performa 611x Series, Power Macintosh 6100 Series and Workgroup 6150 Series.