Motherboard Power Controller Fault

The general power output controller for higher current, heat large, if the control chip, or poor quality or cooling Manifold poor
A high failure rate. As well as its surrounding long-term power supply filter capacitor for high-temperature environment, will be made because the electrolyte dry

Into a failure, which led to increased power output of the ripple caused by the motherboard job instability.
The fault does not arise in a board, of which 60% of the failures will lead to the motherboard could not start work; 35%
Failure will make the motherboard not working correctly; another 5% of the special random failure, the performance of the state of instability for the motherboard.
11. Check the motherboard failures common method of
Motherboard failure is often manifested in the system failed to start, the screen no display and intuitive judgments are difficult to fault phenomena. Here are
Maintenance methods have advantages and limitations, are often used in combination.
1. Cleaning Method
Can be used to brush gently brush the dust on the motherboard In addition, a number of add-in cards on the motherboard, chip pin form, often
Because of poor contact pin oxidation. Eraser can be used to the surface oxide layer, re-plug.
2. Observation
Repeated view of the board and needed repairs to see if the plugs and sockets is skew, resistance, capacitance pin is touching the surface,
Is burned, the chip surface is cracking, copper on the motherboard is blown. Would also like to see if there is foreign matter falling into the motherboard
Between components. Encountered in areas of doubt, you can look at the amount of help multimeter. Touch the surface of some chips, such as the
Abnormal hot fruit can try for a chip.
3. Resistance, voltage measurement method
To prevent accidents, what should be measured before the power-board +5 V power supply and ground (GND) between the electrical
Resistance. The most simple way is to measure the power chip resistor between the pin and the ground. The power plug is not inserted, the resistance
In general should be 300Ω, the minimum should not be less than 100Ω. Test-retest about reverse resistance values, slightly different, but not phase
Difference is too large. If the positive and negative or close to the resistance of a small turn-on, it shows a short circuit occurs, you should check the reasons for short. Rise to this
The reasons for such phenomena as the following:
(1) system has been the breakdown of the chip board. In general more difficult to rule out such a failure. For example, TTL chips (LS Series)
The +5 V connected together, can absorb +5 V pin on the solder, so that suspension, one by one measurement, in order to identify fault-chip
Sub. If we adopt the secant method will certainly affect the life of the motherboard. (2) The board on any damage to the resistance and capacitance. (3)
Conductive debris on the board there. When excluding short-circuit fault, the plug in all the I / O cards, measuring +5 V, +12 V and the
To whether the short-circuit. +12 V in particular, whether it collide with the surrounding signal. When there is a good hand the same type of motherboard
When measurement of resistance can also be measured on-board method of doubt, by contrast, you can quickly find chip failures
When these steps were not bear fruit, you can plug in the power supply power-measurement. Generally measured power supply +5 V and +12 V.
When they find out too much of a voltage deviation from the standard, you can cut through the separation or some wire or unplug some chips and then
Measuring voltage. When cut a certain wire or unplug a piece of silicon, if the voltage becomes normal, then this leads to a meta-lead devices
Documents or pull down the chip is the failures.
4. Swap exchange
The host system to produce failure for various reasons, such as the motherboard’s own fault or I / O bus on a variety of card failure would
Can cause the system not functioning correctly. Using plug repair method is to determine the fault in the motherboard or I / O devices fast-track approach. The
Way is to shut down the plug-in board-by-block pull out, pull out a board on the start of each observation of the machine running, once pulled out of a
Block after the board is running normally, then the cause of the malfunction is that the plug-in board failure or the corresponding I / O bus slots and the load circuit so
Barrier. If the pull all the plug-in board to start after the system is still not normal, then the fault is likely on the motherboard. Exchange method using real
Terms of quality is to the same type plug-in board, consistent with the way the bus, feature the same plug-in board or the same model chip-chip phase with each other
Mutual exchange, according to the changes in the phenomenon of failure to determine failures. This method is used for easy plug maintenance environment, such as
Memory self-test error, the same interchangeable memory chips or memory to determine the cause of troubles.
5. Static and dynamic measurement and analysis method
(1) The static measurement: Let the board be suspended in a close-up state, by the principles of logic or chip output and
Enter the logical relationship between the use multimeter or logic level pen measuring the relevant points to analyze and judge the cause of troubles.
(2) Dynamic Measurement and Analysis of Law: the preparation of specific procedures or artificial assertion normal conditions, the machine is running
Using oscilloscope to observe the waveform components, and compared with the normal waveform to determine fault location.
6. Simplest to most sophisticated and integrated method to determine the composition of Principle
With the extensive application of large scale integrated circuit, the control logic on the motherboard integrated more and more, its logic right
Is increasingly difficult to determine by measuring. The logic can be used to determine the relationship between the first chip and a simple resistance-capacitance components, will be so
Barrier concentrated in the logical relationship is hard to determine the large-scale integrated circuit chips.
7. Software diagnostics
Through random diagnostic procedures, special maintenance diagnostics card and based on various technical parameters (such as interface address), self-compiled specifically
With diagnostic procedures to aid in hardware maintenance can achieve a multiplier effect. Principle of program testing method is to use the software to send the number of
It is, order, by reading the line status, and a chip (such as the register) state to identify the fault position. This method is often used
For inspections in a variety of interface circuit faults and the various circuit parameters with the address. However, this method applied on the premise that CPU and base
Bus operating normally, be able to run the diagnostic software that can run the installation on the I / O bus slots on the diagnosis of cards.
Prepared by the diagnostic procedures to be strict, comprehensive and focused, enabling emergence of certain key parts of a regular signal, can be
Occasional failure of repeated testing, and can show an error of record.