What is the south bridge of the motherboard responsible for? How to check the south bridge on the motherboard


Northern and south bridge s are very important for the operation of the computer. They have just such a name because of comparison with the cardinal points, because the north bridge is located on top, and the south bridge is on the opposite side. Very often they are the problem with the malfunction of the entire device, so you should follow some rules that will help preserve the life of the elements.

North Bridge.

The North Bridge is an important part. It is responsible for the interaction of the processor, video card and RAM. In addition, it determines the operating speed of the above elements and connects them to the south bridge. Because of this, the northbridge gets very hot. Therefore, it is necessarily equipped with a passive radiator or additional system cooling.

Recently, devices that come with a video processor are very popular. Despite the fact that this is not reflected in the best way in the video, there is an additional load on this element. Therefore, if you play modern games or use serious programs, then you should not choose this “design”. And if you don’t do anything like that, then this a budget option will suit you perfectly.

Based on the following visible consequences, it can be determined that the breakdown lies precisely in this element:

  • The computer does not react in any way to the power button (the indicators light up, but nothing else happens, or it does not turn on the first time);
  • The device suddenly began to reboot itself (but this only works if the computer is scanned for viruses);
  • There is no image;
  • Appearance short signals when turned on (the device cannot find RAM);
  • Appearances " blue screen death" (not the most obvious sign, but as an option).

It should be noted that the worst thing for the northbridge is overheating. Therefore, you should carefully monitor your device: often clean your computer from dust and monitor its temperature (this can be done using special programs). You should think about it if the temperature of this element reaches 50-60 degrees Celsius. If your device is a laptop, then under no circumstances should you work with it on a soft surface, including the human body.

If the fault is in the north bridge, then it needs to be replaced as soon as possible.

South Bridge

The South Bridge is an equally important part. It is an I/O controller because every peripheral device communicates with it. The south bridge is responsible for various controllers, power management, and even the BIOS, and so on. It has many functions, but it mainly works only with slow processors. Therefore, it is not in danger of overheating. But if you don’t clean your laptop on time, you’ll soon have to contact service center.

Possible visible consequences of a breakdown of the south bridge are as follows:

  • USB ports failure. Not necessarily partially, even the failure of one of them indicates a problem with this element;
  • Problems with the touchpad and keyboard;
  • The device is not working or charging properly;
  • Refusal DVD drive or hard drive.

Just like for the north bridge, overheating has a very bad effect on the operation of the south bridge. A timely cleaning procedure and following operating instructions can reduce the chances of a breakdown. In addition, you need to monitor what device you “push” into your computer: you should not connect too powerful or low-quality devices. Use your ports as intended.

It should be noted that the computer is functional even if the south bridge is burned out. True, this state does not last very long. Due to a breakdown, the computer will become very hot, which will have a bad effect on motherboard. If you do not solve the problem in time, you will soon have to change it too.

Causes of bridge failures

In addition to overheating, there are a number of other reasons why these elements may fail:

  • Factory defects are not the most common reason, but they still exist. IN in this case you just need to make a replacement;
  • Liquid ingress - if liquid suddenly gets inside the device, then short circuit Can burn down your entire computer in a couple of minutes.
  • Physical deformation – occurs as a result of falling of the device. Small parts may become detached from the bridges;
  • Power surges - they not only have a bad effect on the operation of bridges, but also on the entire computer as a whole. Therefore, to avoid this, it is better to install a voltage stabilizer.

Thus, you should take care of the north and south bridges of your device. Observing simple rules operation, you will not only extend the life of these elements, but also take care of normal operation computer, and also save your budget.

Sometimes situations arise when your computer stops working and you have to take it to a service center. In some cases, you can hear that the South Bridge is faulty and the entire motherboard needs to be replaced. The diagnosis seems to be clear, but not every user knows the concepts of South Bridge and North Bridge. These two computer devices, or rather the motherboard, are the main functional controllers responsible for the operation of all other components of the motherboard. Together, these bridges form a chipset, but still each of them is responsible for its own functions. These square-shaped chips received such an unusual name due to their location on mother card: North is at the top under the processor, and South is at the bottom.

North Bridge

The north bridge is a control device that is responsible for the interaction of the motherboard with your computer's RAM, video card and processor. In addition, this chipset element not only interacts, but also controls the speed of operation of the components described above. One of the parts of the Northbridge is the built-in video adapter found in some modern motherboards - the so-called integrated video card. Accordingly, this bridge additionally controls the bus of the device responsible for transmitting the image to the monitor and its speed. Additionally, the North Bridge connects all mentioned devices to the South Bridge. As a rule, this chip has its own passive cooling, that is, a radiator is installed, it is less common to see active cooling using a cooler. This is done because the temperature of the North Bridge is about 30 degrees higher than the temperature of its South Bridge. This is due to the processing of commands from the most active components of the system and the close proximity to the processor, due to which heating occurs from the outside.

South Bridge

The South Bridge is a functional controller, the main function of which is to implement the so-called “slow” connections, which include various buses, USB, SATA and LAN controllers, power supply system, BIOS and even the clock, in general, the list is quite large. That is why the failure of the South Bridge leads to the need to replace the entire motherboard. Considering that this controller interacts directly with external devices, the cause of the breakdown may be ordinary overheating, triggered, for example, by a short circuit.

South bridge failure is the most common problem on boards using i845/i865/i848 series chipsets. The main reason is the burnout of the USB controller built directly into the south bridge. However, the purpose of this article is not to search for reasons, but to find ways to “bring back to life” such boards.

In the event of a failure due to the “dying” of the USB controller (in the south bridge), the following main options for the behavior of the motherboard are possible:
1. The board does not turn on (forced start gives zeros on the postcard), the south bridge is already heating up from the standby power supply. The board starts but freezes at POST code 25 (for Award BIOS 6.0) or D0 (for AMIBIOS8).
2.The board starts, but freezes at POST code 25 (for Award BIOS 6.0) or D0 (for AMIBIOS8).
Solution methods:

1. Restoration using the "annealing" method
The first case is especially typical for Asus boards P4P800 series. With this option, you can and should use the “annealing” method. What does "annealing" mean? This means that in order to prevent power shortening of already burnt out parts (inside the south bridge), a deliberately “burning” voltage is applied to them until they finally burn out, thus ceasing to interfere with the functioning of all the others, which, as a rule, remain perfectly serviceable , blocks inside the chip.
"Annealing" of standby power supply
We check whether the duty 5V and 3.3V are sagging.
We supply standby power and check whether the standby 5V and 3.3V are sagging. If yes, we supply “power” 5V/3.3V to them and briefly turn on the power supply (with a jumper on PS_ON). We remove all jumpers and check the control voltages. “We got up” - good, if we didn’t get up - we try again, and several more times, it doesn’t work - we leave the “power” jumpers and move on.
"Annealing" the load of capacitors connected to the outputs of internal standby sources
We look for three capacitors on the board connected to the outputs of internal standby 1.5V sources (VCCSUS1_5A,B,C) - at least one of them has dropped to 0.2..0.4V (as a rule, this is only VCCSUS1_5A) and “anneal” its load. To do this, first apply 1.5V (you can use Vcc installed processor, possible with Vmch/agp). If this does not help, we make several short-term short circuits to 2.5V memory power supply or, in extreme cases, 3.3V. It is dangerous to burn out five volts - there is a possibility that the south bridge will die for good. If 2.5V does not help, before applying 3.3, it is recommended to try 3.3VSB first (as a relatively low-current source). If as a result the voltage rises to the required 1.5V, then the operation was successful! (The temperature of the south bridge should decrease by 15-20 degrees compared to what it was before the “annealing”).

2. Recovery by flashing the BIOS
The second case is typical for maternal Gigabyte boards 8IPE1000-series. In this case, in general, it may be enough just to flash the “correct” BIOS.
Using ProBIOS
To check for the possibility of reviving boards with such a problem (stopping at the 25th postcode for Avard and D0 for AMI), you can and should use a “probios” (tested bios). ProBIOS is special bios, suitable for most motherboards based on i845/i865/i848+ICH4/ICH5 logic. It contains initialization of only “vital” parts of the board (which allows it to be used as a test and for all “other” cases - just repairs), including skipping the procedure in which in “standard” (ordinary, “native”) BIOS board freezes.

So, as a result, we should get a reduction in the heating of the south bridge (by 15-20 degrees compared to the temperature before the “treatment”), as well as a fully functional motherboard. True, adjusted for the missing USB ports, but nothing will prevent you from installing an “external” PCI USB controller and thus getting a completely working system.

Many of you have heard the phrase: “The South Bridge burned down and cannot be restored!” Experienced users will immediately understand what we are talking about, but beginners will wonder where I got some kind of bridge on my computer? I’ll tell you right away that you have two of them, there is also the North Bridge. It is these bridges that we will talk about.

Of course, you can go to the Wikipedia website and find out what the south bridge and north bridge are, but I decided to write in my own words, as I understand it.

“The north and south bridges of the computer (or, more correctly, the motherboard) are two main functional controllers that are responsible for the operation of all components of the motherboard and are called a chipset.”

Let's look at them separately. Let's start with the north bridge.

Northbridge is a bridge that is connected via a bus Front Side Bus directly to the processor, abbreviated as three letters FSB. Typically the northbridge contains a memory controller that assists the processor fast access to memory. The North Bridge is also connected to Accelerated Graphic Port, abbreviated AGP or PCI Express . One of the main functions of the north bridge is to ensure interaction between the motherboard and the processor, as well as determine the operating speed. Part of the northbridge in many modern motherboards is the built-in video adapter. Thus, functional feature The north bridge also controls the video adapter bus and its speed. The north bridge also provides communication between all of the above devices and the south bridge.

South Bridge - connects to the North Bridge, it is slower than the North Bridge. Buses such as, PCI, USB, SATA, IDE controllers etc. B this moment Two types of chipsets are available for products INTEL And AMD. The board also has a processor socket, connectors for installing RAM, TV tuners, network cards, sound cards etc.
In addition to the above IDE, SATA, USB, LAN and other things, the south bridge is also responsible for the SM bus (used to control fans on the board), DMA controller, IRQ controller, system clock, BIOS, APM and ACPI power supply systems, LPC bus Bridge.

As a rule, the failure of the south bridge puts an end to the life of the motherboard. It is the south bridge that is sometimes the first shield to take the “blow”. Due to technological features, this is so. The reasons for the “death” of the south bridge are an order of magnitude greater than those of the north bridge, because it works directly with “external” devices. So, common cause failure of the South Bridge is a simple overheating caused by a short circuit, for example, of the USB connector. Or there is a power failure on the hard drive. Because in most cases the southbridge is not equipped with a system additional cooling, it overheats and burns out.

Symptoms of malfunction

  • When you turn on the laptop or computer, the cooler starts to spin, the indicators light up, there is no access to the hard drive, there is no image on the screen
  • Laptop, computer may turn off after work in a few seconds
  • After switching on it goes into a cyclic reboot
  • Keyboard, touchpad, USB ports refused to work
  • Incorrect image or its complete absence (sometimes there is when connecting a monitor)
  • The equipment starts to turn on only after several attempts

For different manufacturers and models have different symptoms of malfunctions, which can only be substantiated after detailed diagnostics.

Reasons for the breakdown of the North and South Bridges

The cause of the malfunction can be many factors, such as:

  • Overheat. The most common reason. May occur due to untimely cleaning and replacement of thermally conductive lubricants.
  • Factory defect of the chip. A less common problem, but also has a right to life. There are even laptop models where the manufacturer himself declared low-quality chips, such equipment will sooner or later be 100% repaired (already modified chips are installed as replacements without any problem)
  • Liquid ingress. If liquid gets in, the legs create a short circuit between themselves, which leads to failure of the chip.
  • Physical deformation. When dropped, some balls may come off the system board, and just one ball is enough for the laptop to stop working completely
  • Voltage surge. For example, from a broken battery or power controller

Methods for repairing the South and North Bridges

The concept of repair as such boils down to only one thing, complete replacement of the chip with a new one. Since this is a complex technological device, its repair has no right to life. A reservation can be made only in cases where we're talking about not about the failure of the chip itself (peeling of the chip from the substrate/burnout of elements), but about the contact balls lagging behind the board contacts (however, this rarely happens, more often due to physical impact).

Note, however, that under normal conditions there is no reason for increased heating of the south bridge, but remember that the south bridge is responsible for many devices that could contribute to its overheating and combustion.

Be careful.

That's all. Thank you for reading the article. I hope it was useful to you.


2024 gtavrl.ru.