Lenovo 7844B4U User Manual page 38

DANGER
CAUTION:
Never remove the cover on a power supply or any part that has the following
label attached.
Hazardous voltage, current, and energy levels are present inside any component
that has this label attached. There are no serviceable parts inside these
components. If you suspect a problem with one of these parts, contact a service
technician.
To replace the power supply assembly, do the following:
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User Guide
Hazardous moving parts. Keep fingers and other body parts away.
1. Remove all media from the drives and turn off all attached devices and the
computer. Then, disconnect all power cords from electrical outlets and
disconnect all cables that are connected to the computer.
2. Remove the computer cover. See "Removing the computer cover" on page 14.
3. Remove the front bezel. See "Removing and reinstalling the front bezel" on
page 15.