Fujitsu PRIMERGY TX1330 M4 Upgrade And Maintenance Manual page 146

Power supply unit (PSU)
CAUTION
▶
Keep the dummy cover for future use.
▶
If you remove a PSU and do not immediately replace it with a new
one, a dummy cover must be installed in the bay again to comply
with applicable EMC regulations and satisfy cooling requirements.
Installing a hot-plug PSU
Figure 67: Folding up the handle
▶ Push the handle of the PSU halfway upward in the direction of the arrow.
146 Upgrade and Maintenance Manual TX1330 M4