Chapter 8. Removing Or Replacing A Fru; General Guidelines - Lenovo ThinkPad T490 Hardware Maintenance Manual

Chapter 8. Removing or replacing a FRU

This chapter provides instructions on how to remove or replace a FRU.
CRU statement for customers:
You can resolve some problems with your product with a replacement part you can install yourself, called a
"Customer Replaceable Unit" or "CRU." Some CRUs are designated as self-service CRUs and others are
designated as optional-service CRUs. Installation of self-service CRUs is your responsibility. For optional-
service CRUs, you can either install the CRU yourself or you can request that a Service Provider install the
CRU according to the warranty service for your product. If you intend on installing the CRU, Lenovo will ship
the CRU to you. CRU information and replacement instructions are shipped with your product and are
available from Lenovo at any time upon request. You can find a list of CRUs for your product in this Hardware
Maintenance Manual. An electronic version of this manual can be found at
Documentation and then follow the on-screen instructions to find the manual for your product. You might be
required to return the defective CRU. When return is required: (1) return instructions, a prepaid shipping label,
and a container will be included with the replacement CRU; and (2) you might be charged for the
replacement CRU if Lenovo does not receive the defective CRU within thirty (30) days of your receipt of the
replacement CRU. See your Lenovo Limited Warranty documentation for full details.

General guidelines

When removing or replacing a FRU, be sure to observe the following general guidelines:
1. Do not try to service any computer unless you have been trained and certified. An untrained person runs
the risk of damaging parts.
2. Before replacing any FRU, review Chapter 7 "FRU replacement notices" on page 57.
3. Begin by removing any FRUs that have to be removed before replacing the failing FRU. Any such FRUs
are listed at the beginning of each FRU replacement procedure. Remove them in the order in which they
are listed.
4. Follow the correct sequence in the steps for removing a FRU, as given in the drawings by the numbers in
square callouts.
5. When turning a screw, turn it in the direction as given by the arrow in the drawing.
6. When removing a FRU, move it in the direction as given by the arrow in the drawing.
7. To put the new FRU in place, reverse the removal procedure and follow any notes that pertain to
replacement. For information about connecting and arranging internal cables, see Chapter 6 "Locations"
on page 45.
8. When replacing a FRU, use the correct screws as shown in the replacement procedure.
DANGER
Before removing any FRU, turn off the computer, unplug all power cords from electrical outlets,
remove the battery, and then disconnect any interconnecting cables.
Attention:
• After replacing a FRU, do not turn on the computer until you have made sure 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.
• 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.
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