Dell 3115cn Service Manual page 512

Chapter 3 Removal and Replacement Procedures (RRPs)
Removal 71 FAN (PL13.5.10)
19)
20)
Gnb03226KA
19) Remove the one screw (silver, tap, 32mm) that fix the PLATE DUCT to tha FAN.
20) Remove the PLATE DUCT from the FAN.
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Version 1 2006.11.28