A system board also known as motherboard or mainboard is the main circtuit board in any laptop. Unlike desktop PC system boards, laptop system boards come in thousands of different shapes and sizes. Laptop motherboards are model-specific. In other words, you cannot remove motherboard from a Toshiba laptop and stick it into a Dell laptop. All parts inside a laptop are connected to the system board, either directly via a connector mounted on the system board or through a cable.
In a typical laptop the following ports and components are permanently attached to the system board and cannot be easily removed and replaced without soldering:
1. Hard drive (HDD) connector.
2. CD/DVD drive connector.
3. Memory (RAM) slots.
4. Battery connector.
5. Keyboard connector.
6. Audio (headphone and microphone) jacks.
7. Volume control wheel.
8. USB ports.
9. Eithernet (RJ45 aka network) port.
10. IEEE 1394 (Fire Wire) ports.
11. Video chip and some other components and ports.
System board, processor (CPU) and LCD screen are the most expensive parts in any laptop. In some cases, when one of these three parts fails, it’s cheaper to buy a brand new laptop than replace the failed part. But each case is different so do your research.
The system board is mounted inside the laptop base assembly. In order to remove or replace the motherboard, you’ll have to disassemble the whole laptop.
SYSTEM BOARD FAILURE SYMPTOMS.
When a system board fails, you may experience the following most common problems with your laptop. 1. The laptop is completely dead. There are no LED light activity when you press on the power button or plug in a known good AC power adapter. 2. The laptop starts but the video output on the LCD screen or external monitor is garbled. Most likely this is related to the VGA chip failure. 3. The laptop turns on without video on the screen and the power LED starts flashing. 4. The laptop works fine with AC power adapter but will not charge a known good battery. If that’s the case, most likely there is something wrong with the battery charging circuit or DC power jack.