• South and north bridge on the motherboard. North and south bridges of a computer. What is it

    South Bridge - Burnt!!! Symptoms, causes, repairs

    South Bridge(from the English. Southbridge) (functional controller), also known as an input-output controller hub (from the English. I / OControllerHub (ICH)) is a chip that implements “slow” interactions on the motherboard between the chipset motherboard and its components.

    The south bridge is usually not connected directly to the central processing unit (CPU), unlike the north bridge. North Bridge connects the south bridge with the central processor. The south bridge is responsible for starting the laptop and for the operation of peripherals: PCI cards, USB, hard drives, sound and network.

    Functionally, the south bridge includes:

    • PCI bus controller;
    • ISA bus controller (obsolete);
    • SMBus or I2C bus controller;
    • DMA controller;
    • interrupt controller;
    • PATA (IDE) and SATA controllers;
    • LPC bus controller;
    • Real Time Clock;
    • power management (APM and ACPI);
    • non-volatile BIOS memory(CMOS);
    • AC97 sound controller (optional).

    Optional south bridge may also include Ethernet controller, RAID controllers, USB controllers, FireWire controllers and audio codec.
    Much less often south bridge may include support for keyboard, mouse and serial ports, but usually these devices are connected using another device - a Super I/O (input/output controller).
    Modern south bridges also support the PCI-Express bus.

    Schematic location of the south bridge on the system board:

    It is quite obvious that a malfunction of the south bridge microcircuit entails the failure of the corresponding controllers.

    However, to understand a larger circle of users, we list the main symptoms in which we can most likely talk about a malfunction of the south bridge:

    • Laptop Touchpad does not work;
    • laptop keyboard does not work;
    • All USB ports do not work or work incorrectly (if one USB port does not work, but the others work, most likely the problem is not in the south bridge);
    • there are problems with sound or there is no sound at all (provided that the drivers are installed correctly and the speakers are connected);
    • the network card does not work or Wi-Fi module laptop;
    • the hard drive is not detected in the BIOS;
    • DVD drive does not work;
    • The laptop gets very hot in the area where the south bridge is located;
    • The laptop does not work on battery power or the charge level is displayed incorrectly.
    • Usually, if the south bridge fails (burns out), the laptop continues to function. In it, only the above devices are cut off (all or some of them, depending on the extent of the internal damage). However, there are also cases when the laptop stops turning on completely (there is no response to pressing the start button).

    What are the main reasons why a motherboard's south bridge fails?

    The most common cause of damage to the south bridge is overheating. The reason may be poor contact of the bridge chip with motherboard or a short circuit occurs. A short circuit usually occurs directly in USB connectors. The occurrence of “kazy” usually occurs as a result of incorrect user actions when using various USB devices. Another common reason for the south bridge to burn out is static electricity, which accumulates on a flash drive connected to a laptop. As a result, the charge through the USB port hits the south bridge, causing it to burn out.

    Also, the reason for the frequent failure of the south bridge may be a short circuit due to some liquid getting on the laptop. Do not discount possible mechanical damage due to impacts or falls.

    Treat your laptop with care, carry out preventative cleaning of the cooling system in a timely manner, do not spill various liquids on the laptop, protect it from mechanical damage (shocks and shocks).

    What to do if the south bridge is faulty?

    If it is discovered that the chip is damaged, it is necessary to replace the south bridge of the laptop. Repair the south bridge yourself without availability necessary equipment and materials – impossible! The work of replacing the south bridge can only be performed by a qualified technician with practical experience in performing such work.

    Many of you have heard the phrase: “The South Bridge burned down and cannot be restored!” Advanced users they 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.

    "Northern and south bridges computer (or, more correctly, the motherboard) are two main functional controllers that are responsible for the operation of all components motherboard and are called a chipset (from the English 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 quick 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 at the 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. Thus, a common cause of failure of the South Bridge is simple overheating caused by a short circuit, for example, of a USB connector. Or power failure 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 rotate, the indicators light up, there is no access to 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 one 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; sooner or later such equipment will 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 comes down to only one thing, complete replacement chip for 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 are not talking about the failure of the chip itself (peeling of the microcircuit from the substrate / burnout of elements), but about 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.

    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 shortening of the power supply to already burnt out parts (inside the south bridge), a deliberately “burning” voltage is supplied 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, we first supply 1.5V (possibly from Vcc of the installed processor, or from 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.

    Laptops and personal computers- very complex devices. There are so many microchips in them that an untrained user could never have dreamed of. Often, all these “pieces of hardware” tend to fail. In service centers they get off with the faceless wording “the north bridge of the motherboard has burned out.” And what kind of bridge this is and where it came from on this very board - God knows. Severe IT specialists are not going to explain the structure of a computer to mere mortals. But you need to know this, since the problem is very serious and occurs quite often. This is what we will talk about now.

    What is northbridge

    The north bridge is a controller on the motherboard that is responsible for the operation of some of its very important components. Often this bridge is paired with a built-in graphics core(especially on laptops). This is not surprising, because the bridge is responsible for the operation of the video adapter, central processor, RAM and other critical computer components. It is by his grace that the entire multi-component system works. It is named so because of its location. But not because of the temperature.

    It’s a paradox, but much “colder” than the northern one. This is due to the fact that the northbridge is in close proximity to the processor and video card. This affects his temperature in the most negative way. That’s why it is equipped with an additional cooler or cooling radiator. In addition, this bridge is usually installed in the upper part of the body. And hot air, as you know, rises. Hence the additional load on this element. Is it worth mentioning that this particular component of the motherboard burns out first?

    Signs of failure

    It's pretty simple. Since the north bridge of a laptop or PC is responsible for the operation essential components, then diagnosing its breakdown is quite simple. Just turn on the computer. The first sign will be that there will be no image on the screen. There may also be no access to the hard drive. RAM won't load either. As a result, you will hear a characteristic beep in the form of a nasty squeak.

    It may also be a symptom cyclic reboot computer. It all depends on the degree of damage to the component. Another common symptom may be that the computer turns on after the fifth or even tenth time. If such symptoms occur, then your northbridge on your laptop or PC is seriously damaged. And you shouldn’t delay this, because you can lose all the other components of the computer that are still working properly.

    Causes of failure

    There are a great many of them. Therefore, it is impossible to immediately understand what happened. The most common reason- overheating. The North Bridge simply burns out due to excess permissible temperature. This kind of thing occurs when the component is not cooled sufficiently. Physical damage from impact is also possible. Moreover, it is not necessary to “pound” the motherboard itself. The controller is very fragile. A little push is enough for him. The last reason- factory defect. It is extremely rare. Manufacturers usually warn users that the motherboard contains a chip with a flaw. It's a matter of time when it flies off.

    The north and south bridge are quite finicky components. All they need is a slight shake, a minor overheat or a power surge - and that’s it, they’re dead. By the way, liquid getting inside the computer is also a common cause of failure. Enough for the smallest drop to hit the contact, a short circuit immediately occurs and the controller burns out. And without this control element, PC operation is impossible.

    Repair

    You won't be able to repair a faulty north bridge with your own hands. This is a complex device that is produced by specialized robots. Such precision is inaccessible to humans. Therefore, in service centers no one will tinker with the controller. There is only one way out - to replace the bridge. The quality of the replacement depends on the specific master. It is not recommended to give your laptops and PCs to the hands of “traditional craftsmen”, because these comrades can kill everything there. It is better to use the services of professionals.

    If you have a motherboard with a obviously faulty controller (which has been confirmed by the manufacturer), then it is better not to wait for hour X. The North Bridge will be replaced under warranty completely free of charge at an authorized service center manufacturer. But it’s better not to delay this, because the consequences can be very sad.

    Prevention

    In order to avoid failure of this component of the motherboard, you just need to follow not very complicated operating rules. Firstly, you need to regularly clean the case from dust and dirt. Particular attention should be paid to coolers and other components of the cooling system. Because if you let everything take its course, the northern bridge will simply burn out, unable to withstand high temperature. Also, you should always check the cooling system for functionality. If any cooler fails, it should be replaced immediately.

    Secondly, never expose your laptop or PC to physical impact. This also has a detrimental effect on this component. Thirdly, keep pets away from laptops and PCs. Their fur very quickly clogs the cooling system. The result is overheating and failure of the bridge. Fourth, never drink anything near a laptop or PC. One drop of liquid leaking onto the motherboard is enough for the north bridge to “play into the box”.

    Conclusion

    Now you know what the north bridge of a computer motherboard is, what it serves and what it is afraid of. Compliance simple rules Safe operation of your computer will help you avoid failure of this finicky component. Diagnosing a malfunction of this component of the motherboard is also very simple. If the PC does not start, reboots and there is no image, then with a high degree of probability we can say that the north bridge has died. It is impossible to repair it - only change it. However, it is easier to replace it than the entire motherboard. Treat your computer with care, and you will never have such problems.

    So, first, a little theory.

    A common laptop failure is a burnt out south bridge. Our clients who hand over laptops for repairs ask the question, what is the south bridge responsible for in a laptop? To answer that this is a south bridge and clarify this popular question, we decided to write a short commentary about this popular microcircuit.

    South Bridge– translated from English (Southbridge) – no less important is the controller microcircuit that ensures operation large number functionality of a modern laptop or PC. If your IDE, SATA, USB, LAN, BIOS, APM and ACPI power supply systems, LPC Bridge bus, Embeded Audio, SM bus (responsible for the rotation speed of coolers), DMA controller, IRQ controller have stopped working, you can be sure , that you need to change (resolder) the south bridge. This microcircuit, although not as productive as the north bridge, also performs a number of vital functions. necessary for a laptop functions. The south bridge transmits data to the north bridge, which in turn sends it to the processor for processing. In older laptop models, the tasks of this chip also included data processing on PCI buses, PCIe and ISA. Can be rephrased from technical to simple spoken language that the southbridge is at the forefront of dealing with the user and external technical irritants, such as, for example, installing a faulty laptop USB flash drives First of all, it will put at risk the operation of the south bridge, which could easily burn out because of this. Short circuits any of the above ports lead to an increase in the temperature of this chip, which often does not have additional cooling, which leads to overheating.

    Read more: