Motherboard Boot Failure Analysis

Motherboard boot Failure Analysis and solution one:

The first is the boot, if the power light is not lit, the monitor black screen, the other components do not have any reaction, then the general people will immediately think of whether the power out of the problem, but in fact, the motherboard is bad will appear this situation.

In a computer, the start-up of a computer requires a start-up device, generally speaking, the device is on the motherboard, which has a main starting capacitor, if the capacitor damage, there will be nothing to respond to the situation. This capacitor is very small, but it is easy to find: Pick up the motherboard, careful observation, you will find an iron electrolytic capacitor, it is usually surrounded by a wire. With such an obvious feature, it should be easy to find.

The solution is to replace a good capacitor. This kind of problem is more common, I have two friends is because of this problem and can not start the machine, one because has been over the warranty period, but had to get to the computer city repair, that is, change the capacitor. Another Buddy is OK, anyway, the replacement period has not been, simply to find a merchant for a new motherboard back, after all, the problem is small, solve it is more troublesome.

There is also the interface problem with the motherboard. Because the motherboard to take a lot of accessories, if an interface is broken, it means that the accessories can not be used, this will not start, such as: The motherboard of the AGP slot problem, it may not be able to start. In fact, this problem is strictly not due to the inability to start, it may have been started, but can not be displayed, so finally I still put it to this aspect.

I now use the computer has such a problem, the AGP slot is very loose, the card's Gold fingers and groove contact point contact, so there is no way to show, to plug a few times, to find the right direction. There is a problem with the IDE interface so that the hard drive cannot be detected at all, let alone enter the system.

In addition, there is the problem of memory slots, if you turn on the machine, the speaker in the host "beep, beep" sound, and other components do not have any reflection, this may be the memory slot is not (of course, may be the memory is bad, but now we do not consider the memory of the problem). There are other interfaces, such as CPU interface, here I will not repeat.

The most important thing on the motherboard is the chip. General non-integrated motherboards have two chips, one is the South bridge chip, one is North Bridge chip. In the traditional sense, the main task of North Bridge is as the main interface of CPU and system Exchange, in which memory controller function is the most important. In addition, the North Bridge is also responsible for communication with the Nan Qiao.

The South Bridge features a wide variety of functions, including disk controllers, audio synthesis, Ethernet network controller, as well as our frequent contact is also necessary I/O interface (such as serial port, PS/2 port, etc.). If the North Bridge chip is broken, then the CPU and the system's main interface exchange will have problems, and then the CPU on the computer will not work. Since the central processing unit can not be used, it can be imagined, and the memory control function also lost, the computer did not have two parts of the support, where still show ah?

The bridge chip once the problem, the computer also loses the disk controller function, this and without the hard drive is no different. See how important these two chips are! If the two chips burn down, that is a fatal wound, in the computer city is no way to repair, unless sent back to the original to repair. I dormitory many computers, there is a motherboard has been such a problem, the South Bridge chip burned, the warranty period has passed, had to buy a piece. If it is the integration of the motherboard is even worse, because it has only one chip, if the problem can be worse than the general motherboard problems. So in the installation or use, we must pay attention to these details, so as not to cause unnecessary losses.

Problems with the motherboard cause different startup failures. And the structure of each motherboard is not necessarily the same, so the problem is different, there is no way to describe all the situation, I just put their own experience and experience to work together to learn from each other, if there are errors or omissions or hope that we can give suggestions, I can learn knowledge from it.

Motherboard boot Failure Analysis and solution two:

One, the suspicion of host power supply or bad

First, the power supply, press the switch, if not power, and then unplug the main engine power, with tweezers to the Green Line and black lines short-circuit, look at the power supply fan does not, if the turn, indicating the power is good, failure in the host.

Suspected host switch is good or bad: and then the ATX power cord and the motherboard, the motherboard on the switch needle, reset needle, such as pull up, with tweezers short-circuit switch needle trigger power switch, see can boot, if you can, it is the main engine box switch bad, the main box switch to remove the cleaning. If the short-circuit switch needle trigger power or not boot, the motherboard really can not trigger the boot, the motherboard from the chassis to be removed from the overhaul. Remove the motherboard and clean the dust off the board before it prevents maintenance. First, see if the motherboard has no components burned, drum kit, the computer board has no burnt, disconnected. Put the motherboard, insert the fake load, plug in the power, test card, do a good job of overhaul preparation

Second, when the motherboard does not have power

First, by imposing electrical method to locate the motherboard does not power the specific fault circuit. That is, a direct short circuit to connect the green and black lines. If this can be powered up at this point the fault in the soft boot circuit itself. If you can not add electricity at this time, indicating a serious short-circuit phenomenon. ATX Power supply internal protection, it does not allow itself to output voltage to the ground, so the power supply is automatically protected. There may be short circuit, yellow line short circuit, Purple Line short circuit or the main power supply side of the CPU short-circuit. The above short-circuit phenomenon, in the actual motherboard failure occurred in any one will appear forced to add electricity and not power.

For the red line short circuit may be the main board of a field effect tube short-circuit or Power Manager short circuit, there is a door circuit short-circuit or I/O short-circuit, as well as a bridge short-circuit, there may be a 5V filter capacitor short-circuit. Measure the 5V ATX value or power supply tube to the ground number of the eulogy owed 穸 margin Fontanel, u5 mu margin jue  stool about 380 ohms, then you are obviously measuring the power supply tube to the ground 0 ohms or nearly 0 ohms, this time must be said that the motherboard chip to the ground short-circuit phenomenon caused by ATX protection.

For Yellow Line 12V short circuit is usually the power management itself and 12V filter capacitor short-circuit, for 12V short-circuit also may be a serial chip problem.

For the Purple Line short circuit may be the South Bridge, I/O, Fet and gate circuits, as well as the Purple Line filter capacitor and violet line voltage regulator diode caused.

For the CPU main power supply short-circuit may be FET, Power Manager and main power filter capacitor. For P4 motherboard, the CPU main power supply short circuit may also be the North bridge short circuit. Detect the ATX power cord to the ground short circuit, and then run the circuit along the line to find the relevant damaged components, replaced.

Third, if forced to add electricity can be added to the fault in the soft secret fault itself, at this point should focus on the soft boot circuit itself and the soft boot circuit has links to some other circuits.

1, COMs batteries, some motherboards, battery power is not enough to boot, but most of the motherboard does not have a battery does not affect the boot. Normally coms battery it is a voltage of more than 2.6V, sometimes

2.6V-3.3V about the voltage, this should also pay attention to.

2, COMs jumper, COMs jumper is not correct also can not boot, is generally jumping on the one or two is correct, the third is grounded, if the jump on the second third needle can not boot, attention. Some of the motherboard jumper jump wrong, you can boot, because the real crystal oscillator power supply is provided by the Purple Line.

3, measuring power switch needle has no 3.3V or 5V voltage, power switch needle is a pin is grounded, a needle from the purple 5V supply, the middle will pass some door circuit, resistors and other electronic components, If there is no 5V or 3.3 voltage to the switch needle, run the circuit, from the ATX power supply purple 5V to the components between the two look at that damage, replace.