Delta PCS100 Maintenance Manual page 171

Maintenance
8. Once the IGBT HSK cover is removed, the screws securing the IGBT fan module are exposed.
Locate the nuts above the fan module assembly, see the following figure, and remove them.
9. There are thumb screws below the nuts, which were just removed. Loosen the thumb screws
10. Remove the IGBT fan module.
Figure 240. Removing an IGBT Fan Module
Maintenance Manual 159