Today we will finish the disassembly of our Aspire One D250 by removing the WLAN module, system board and display assembly. Meanwhile, while the system rboard is outside the body of the laptop, we will use the opportunity to improve the cooling process in a few simple steps and reduce both the heat and the noise emitted from the laptop. Let’s see.
1. Disconnect the antenna cables from the WLAN module and remove the screw that secures the module to the system board.
2. Remove the WLAN module from the mini Pci-e slot.
3. Disconnect the LCD display cable from the system board.
4. Disconnect the power cable (coming from the DC power jack) from the system board.
5. Remove the screw that secures the extension board containing the card reader, two of the USB ports and both the power and data SATA connectors.
6. Gently lift the left edge of the board and remove it at an angle in order to release it from the base enclosure.
7. Turn the extension board upside down and disconnect the cable that connects it to the system board.
8. Disconnect the speakers cable and remove the screw (in the upper right corner) that secures the system board to the base enclosure.
9. Carefully lift the right edge of the motherboard, then slide it a few millimeters to the left to disengage the sound and VGA connectors (located on the opposite side) from the base enclosure.
10. Now that the system board is removed you need to remove all four screws securing the heat sink assembly to the system board, disconnect the fan cable and remove the heat sink assembly.
In this laptop the heat from the CPU is conducted to the heat sink through a thermal-pad, while the heat from the northbridge passes through a thermal paste before reaching the heat sink. Generally thermal paste is used for filling the microscopic air-gaps in both the chip and the heat sink surfaces, as they are not always perfectly smooth. However, as you can see in the picture below, in this model the heat sink does not fit tightly to the north bridge, which creates a gap of about half a millimeter, requiring a thicker layer of thermal paste. Unfortunately such a large amount of thermal paste always acts as an insulator rather than a thermal conductor, which in most cases causes overheating and the best solution would be replacement with another more effective thermal-conductive material.
I solved the problem using a silicone thermal pad taken from a faulty PSU, that fit perfectly in the gap between the north bridge and the heat sink. Of course before that I had cleaned the remnants of the old thermal paste using a cotton swab moistened with alcohol-based solvent.
In addition I removed the plastic filter from the air vents on the base enclosure just below the north bridge chip. This increases the possibility of dust penetration into the laptop, but it also significantly improves the cooling process allowing more air to pass through the heat sink. However, you do not need to worry about dust because Aspire One D250 doesn’t contain a stacked fin heat sink (like most laptops) which means that there is no barrier in the way of air flow where dust may accumulate. Instead, it is easily blown by the fan through the air vents on left side of the base enclosure.
11. Finally you can separate the display assembly from the base enclosure by removing the four screws (two screws on each henge) fixing both parts together.
12. When ready, carefully lift up the display assembly and remove it.