Lenovo 28479WU Hardware Maintenance Manual - Page 90

For ThinkPad Edge 14" and E40: 1 2 2 3 3 3 3 4 Step 1 2 3 Screw (quantity) M2 × 2 mm, wafer-head, nylon-coated (1) M2 × 3 mm, wafer-head, nylon-coated (2) M2 × 5 mm, wafer-head, nylon-coated (4) Color Silver Black Black Torque 0.181 Nm (1.85 kgf-cm) 0.181 Nm (1.85 kgfcm) 0.181 Nm (1.85 kgfcm) 1170 System board assembly Important notices for handling the system board: When handling the system board, bear the following in mind. • The system board has an accelerometer, which can be broken by applying several thousands of G-forces. Note: Dropping a system board from a height of as little as 6 inches so that it falls flat on a hard bench can subject the accelerometer to as much as 6,000 G's of shock. • Be careful not to drop the system board on a bench top that has a hard surface, such as metal, wood, or composite. • If a system board is dropped, you must test it, using PC-Doctor for DOS, to make sure that the hard disk drive Active Protection SystemTM still functions (see below). Note: If the test shows that hard disk drive Active Protection System is not functioning, be sure to document the drop in any reject report, and replace the system board. • Avoid rough handling of any kind. • At every point in the process, be sure not to drop or stack the system board. • If you put a system board down, be sure to put it only on a padded surface such as an ESD mat or conductive corrugated material. After replacing the system board, run PC-Doctor for DOS to make sure that hard disk drive Active Protection System still functions. The procedure is as follows: 84 Hardware Maintenance Manual