Lenovo 20WJ001HGE, Hardware Maintenance Manual

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3. Follow the correct sequence in the steps for removing an FRU, as shown in the illustrations by the
numbers in square callouts.
4. When removing an FRU, move it in the direction as shown by the arrow in the illustration.
5. To install a new FRU in place, perform the removal procedure in reverse and follow any notes that
pertain to replacement.
6. When replacing an FRU, carefully retain and reuse all screws.
7. When replacing the base cover, reapply all labels that come with the replacement base cover. If some
original labels are not included with the replacement base cover, peal them off from the original base
cover and paste them on the replacement base cover.
DANGER
Before removing any FRU or CRU, shut down the computer and unplug all power cords from
electrical outlets.
Attention: After replacing an FRU, do not turn on the computer until you have ensured that all screws,
springs, and other small parts are in place and none are loose inside the computer. Verify this by shaking the
computer gently and listening for rattling sounds. Metallic parts or metal flakes can cause electrical short
circuits.
Attention: The system board is sensitive to and can be damaged by ESD. Before touching it, establish
personal grounding by touching a ground point with one hand or by using an ESD strap (P/N 6405959).
Remove the lower case
Make sure the computer has been shut down before servicing the computer.
Step 1. Place the computer upside down on a flat surface.
Step 2. Remove nine screws.
Figure 2. Remove nine screws
Screw specifications Number of screws
M2.0 x L3.5 9
28
Hardware Maintenance Manual