166 Chapter 6 Removal and replacement C8523-90921 4 Remove two screws (callout 4) and remove the upper rail (cal lout 5). 4 5 Figure 157. Power supply assembly (3 of 6) 5 Unlock the connector guide claw (callout 6). 6 Figure 158. Power supply assembly (4 of 6) Power supply assembly (3 of 6) 5 Unlock the connector guide claw (callout 6).