Lenovo N21 Chromebook Hardware Maintenance Manual - Lenovo N21 Chromebook - Page 33

Chapter 4. Removing a FRU or CRU General guidelines When removing or replacing a FRU, ensure that you 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. 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. 3. Follow the correct sequence in the steps for removing a FRU, as shown in the illustrations by the numbers in square callouts. 4. When removing a 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 a FRU, carefully retain and reuse all screws. If screws are missing, look up the Lenovo parts numbers in Appendix C "Lenovo part numbers of screws used on N21 Chromebook" on page 49 for replacement screws and order them through the Lenovo CRM system. 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. Refer to Appendix E "Label locations" on page 53 for the layout of labels on the back side of the base cover. DANGER Before removing any FRU or CRU, shut down the computer and unplug all power cords from electrical outlets. Attention: After replacing a 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 upper case and the battery Step 1. Pry the four rubbers out of their recesses 1 2 3 4 . © Copyright Lenovo 2015 27