The motherboard does not have the electricity maintenance method

The motherboard does not have the electricity maintenance method:

First, the motherboard does not have the electricity maintenance method and the example

Motherboard does not power on the fault, in the motherboard maintenance is more common, the frequency is also more. From the motherboard maintenance point of view, the motherboard is not on the electrical failure of most of the relatively good repair. Because the motherboard update speed is very fast, the motherboard board type is also more, some motherboards do not have the power to repair more difficult. As long as everyone in the maintenance process correctly master the maintenance process, repair may be more convenient. Here to introduce you to the motherboard on the electrical maintenance of the process of general maintenance ideas, I hope you have to help repair the motherboard. Inspection of appearance

When we get a motherboard repair, first do not rush to power, you should first check the appearance of the motherboard.

1, check the main components on the motherboard there is no burn traces, focusing on the north-South Bridge, I/O, power supply mos tube, a variety of slots. If it is found that there is obvious burns, damage, the first to be burned, damaged parts to be replaced.

2, check the motherboard on the PCB whether there are scratches, cut off, PCB burning, drop parts and other man-made failures, such as such a failure, the first to fill the line, fill the work. The main direction of observation is the edge of the motherboard and the back.

Second, before the ATX power supply measurement

Motherboard before power to the first to use a multimeter diode file to measure whether there is a short circuit on the motherboard (its method is to hit the diode gear, red table pen grounding black Table pen-voltage test point, we call it to measure the main board of the ground resistance, must not directly on the electricity, otherwise may lead to short-circuit phenomenon more serious, Cause the other components to burn out.

1, measuring the motherboard ATX power supply 3.3V, 5V, 5VSB, 12V voltage whether there is a short circuit phenomenon, generally speaking, its resistance to the earth should be more than 100 euro (various types of plate type will be different, to the company issued the test specification, or to the same product electrical properties OK Good Board), If under 100 euro or smaller resistance, it is possible to be in a short circuit state (the new motherboard, the normal value of 3.3V voltage to the ground is about 100 euro, 12V voltage resistance generally in 400, 500 euro or above, so this 100 euro values can only be used as a reference number). If there is a short circuit, then according to the specific situation of short circuit to arrange the fault.

2, measuring 4PIN of the small ATX plug on the 12V power port on the ground is short (this 12V and the large ATX on the 12V not all the way voltage, this 12V voltage is mainly for the CPU voltage chip and MOS tube supply voltage), if the 12V voltage short-circuit phenomenon, then the CPU to measure the power supply part of the MOS tube, See if there is a breakdown of the phenomenon, in the actual maintenance, most of the tube breakdown, we can first measure the power supply of each phase of the upper tube G, s pole, D, the resistance between s poles to determine is that a phase of the tube is penetrated and replaced, at the same time, it is necessary to note that, in conditions permitting, it is best to replace the entire phase of the upper and lower tubes, and the drive chip will also be replaced.

3, the measurement of the motherboard on the various power supply conversion MOS tube has a short phenomenon, such as memory voltage V_dimm, VDDQ, and so on to determine whether the north-south Bridge has a short-circuit situation (K8N5 motherboard memory without voltage will also cause the motherboard is not on the power).

4, measuring the motherboard 3.3VSB, 1.5VSB waiting for the machine voltage is short circuit, the most common is 3.3VSB and 1.5VSB voltage short-circuit, if the discovery of 3.3VSB short circuit, first to determine whether the network card is damaged (you can measure the interface of the network card caused by the ground resistance to judge), A problem is to first remove the network card chip, and then consider I/O chip (can be measured by the resistance of the mouth to judge), and finally consider whether the South bridge short circuit. If it is found to be a 1.5VSB short-circuit, most of the reason is the South bridge damaged. The most likely to cause a 3.3VSB short-circuit is the South Bridge.

Third, the power of the ATX plug into the measurement,

When the ATX power is plugged in, do not go directly to the motherboard to power on, but to measure the motherboard in the standby state of some important operating voltage is normal. Here we mainly say that the 5VSB, 3.3VSB, 1.5VSB voltage is normal. Measuring the vbat voltage of the motherboard is normal, the abnormal may be CMOS leakage, must check the CMOS power supply circuit. Check whether the 32.768KHZ vibration, these conditions are not normal will cause the motherboard does not power.

POWERSW, ps_on signal level, resistance is normal, abnormal may cause not on the electricity. In addition, the motherboard on the most basic signal flow can be understood as such a process, rtcrst# invalid after the RTC signal is normal, rsmrst# invalid after the dormant signal is normal, slp_s3# sleep signal ps_on# power supply signal, the process of mastering these signals, We can check it step-by-step to find the one step that is not performing properly and to eliminate it. Here is a detailed introduction of the entire power-on on the whole process of electricity:

1, before the ATX power supply, by the motherboard on the battery generated vbat voltage and CMOS jumper on the rtcrst# signal to supply the South Bridge, rctrst# signal used to reset the logic circuit inside the South Bridge, so we should first before the ATX power supply to measure the battery is the power, CMOS jumper

Is there a voltage of about 3 v.

2, check whether the crystal output of 32.768KHz frequency to the South Bridge (on the motherboard of the VIA chipset, but also to measure the crystal vibration of 25MHz whether the vibration)

3, plug in the ATX power supply, check the 5VSB, 3.3VSB, 1.5VSB, wait for the machine voltage is normal conversion out (5VSB and 3.3VSB standby voltage is required on every motherboard).

4, check the rsmrst# signal is 3.3V high level, rsmrst# signal is used to inform the South Bridge 5VSB and 3.3VSB standby voltage normal signal, if this signal is low, the South Bridge received the wrong information, that the corresponding standby voltage is not OK, so will not carry out the next step on the electric action. rsmrst# can be found in I/O chip, in addition to the measurement of rsmrst# signal voltage, but also to measure the rsmrst# signal to the ground resistance, if the rsmrst# signal in the short circuit state is not good, the actual maintenance, multiple fault is I/O chip, South Bridge or rsmrst# The signal of the pull resistance and filter capacitance caused.

6, short connection to the motherboard of the power switch, issued a pwbtn# signal to I/O chip, I/O chip received this signal, after the internal logic processing issued a pwbtin# signal to the South Bridge.

7, the South Bridge received pwbtin# signal, issued slp_s3# signal to I/O chip, I/O chip received this signal after the internal logic processing issued ps_on# signal to ATX power supply, ATX Power received low level of ps_on# signal, began to work, and send out the basic voltage to the motherboard on the various components, complete the electrical process.

Note: The above is the Intel chipset's power flow, via and SIS and other chips of the electrical process is somewhat different, some of which removed the I/O part, that is, trigger the motherboard power switch, directly send out pwbtn# to the South Bridge, South Bridge turned out susb# (ie slp_s3#) Signal to a transistor B-pole, this transistor C-Polar ATX power supply Pson pin, e pole-connected gnd,susb# signal for high level, the transistor C, e polar conduction, will ps_on# pull low, complete the electrical process.