Acer AR160 F1 - Manual (Page 54)

3 System upgrades 38
3 Using a screwdriver, loosen the heatsink screws from the
mainboard.
4 Lift the heat sink away from the processor.
5 Lay down the heat sink in an upright position — with the thermal
patch facing upward. Do not let the thermal patch touch the work
surface.
Installing a heatsink
Caution! The heat sink has a thermal interface material (TIM) on
the underside. Use caution so that you do not damage the TIM. If
a protective film is installed on the TIM, remove it.
1 Remove power from the system and unplug the AC power cord
from the power supply.
2 Do not apply any thermal grease to the heatsink or the CPU die;
the required amount has already been applied.