HP ProDesk 400 G2 Small Form Factor Maintenance And Service Manual page 64

5. Disconnect the fan cable from the system board connector labeled CPUFAN (1), and then lift the heat
sink from atop the processor (2).
When reinstalling the fan sink, make sure that its bottom has been cleaned with an alcohol wipe and fresh
thermal grease has been applied to the top of the processor.
CAUTION:
seat the fan sink on the processor to avoid damage that could require replacing the system board.
Make sure to replace the fan duct. Failure to install the fan duct may cause the computer to overheat.
56 Chapter 4 Removal and replacement procedures: Small Form Factor
Fan sink retaining screws should be tightened in diagonally opposite pairs (as in an X) to evenly