Acer 4020 - Manual (Page 53)

Chapter 3 47
M2.5*6 Remove the IO bezel then
you will see. 2
M2.5*6 Remove the heatsink cover
then you will see. 1
M2.5*6 Remove the HDD cover then
you will see. 1
M2.5*3 Detach the HDD module
then you will see. 1
M2.5*3 Remove the battery then you
will see. 1
Screw Type Location Quantity