Remove The System Board; Screw Specifications; M2 X L3.8 - Lenovo IdeaPad Flex 3 Chromebook Hardware Maintenance Manual

Figure 10. Disconnect the battery pack cable and power board cable
Step 2. Remove three screws, and then remove the power board.
Figure 11. Remove three screws and remove the power board

Screw specifications

M2 x L3.8

Go to
https://support.lenovo.com/partslookup
replacement part:
Power board with cable

Remove the system board

Make sure the following FRUs (or CRUs) have been removed.
36
IdeaPad Flex 3 Chromebook (11", 6) Hardware Maintenance Manual
Number of screws
3
to look up the Lenovo part numbers of the following