Troubleshooting of microcomputer Motherboard

Troubleshooting of microcomputer Motherboard
Boot: (if the instance is not started, the CPU does not work)
Search Procedure: first check the signal and then check the resistance value.

1. Power Supply (jumper overclocking is to change the CPU operating voltage ).

<1> CPU power supply (1.5 V)

Plug in the load to see if 1.5v is available-None, look at the three power supplies of the transistor (A 5 V, on the other two sides, the voltage IC is output to a 4-point multi-volt voltage of the effect tube g pole and a 7-point multi-volt voltage)-IC power supply (12 V/5 V) -- directly provide a voltage power outlet.

(If there is 12 V no output-the IC bad output is not the voltage of 4 o'clock + V and 7 o'clock V)-the IC bad or the transistor is bad

Low CPU operating voltage (for example, the voltage IC output is 10v--3 running or open circuit.

When no CPU is inserted, the operating voltage is normal ., There is no or a low operating voltage when the CPU is plugged in. The voltage IC is bad or the load is short.

<2> vid voltage (5 V)

IC output vid -- blocked -- CPU

2. VTT voltage (1.5 V) (the control line itself has a high or low level)

Power the address data line and power the CPU. The VTT voltage is a transistor (usually a large transistor next to the CPU) that is adjusted and blocked to the CPU data and address line.

3. Other causes of CPU unavailability.

<1> Power Supply

<2> clock

<3> Reset -- none -- the power supply IC has a good signal and the power supply IC has a straight line or crystal oscillator.

<4> incorrect CPU jumper

<5> 32768 crystal oscillator -- no CPU reset is inserted, and CPU reset is normal

<6> CPU data, address, and control line short-circuit or open-circuit may cause the CPU to not work. If the address cannot be delivered to the data center, the address is not working properly.

<7> poor access to CPU deterioration.

<8> pci isa data line, open or short circuit of the address line.

<9> If the BIOS is bad, the power signal of the foot is no CPU, and the power signal does not work, the CPU may work. If the power supply CPU does not work, the BIOS is bad.

<10> door circuit problems

<11> I/O bad

<12> North Bridge power supply (1.5v2.54v)

The North Bridge uses a large transistor to power it. There are many small capacitors in the power supply circuit, that is, the small capacitors next to the North Bridge. These small capacitors are used for power supply filtering. Use the table pen to check the power supply at both ends of the capacitor. Because the capacitor is grounded at one end, you can also check the resistance value. The general resistance value is more than 100 Euro.

The large transistor on the board is used to power components, and some may be used to power multiple components.

4. Check the blocking plant and check the ISAs the center of the North Bridge (such as querying the North Bridge power supply). Check the ISAs the BIOS center to determine whether I/O and Nan Qiao are good or bad. Check the PCI to determine whether the North and South bridges are good or bad.

The BIOS affects the normal operation of the CPU. The capacitor is the signal sent from the CPU to the BIOS.

Rectangular BIOS check capacitor signal, power supplier BIOS -- check 24 initialization signal, power supply clock, reset

The abnormal CPU usage is indicated by oo or ff.

Bad DB02541--BIOS or BIOS Problems

When you enter the BIOS settings and save the settings, restart the system. When a line of English is displayed on the screen, the new machine is displayed. If the BIOS is suspected, the display is not displayed frequently. Sometimes the BIOS settings can be entered in CMOS but cannot be entered into the system.

The problem of re-starting the CMOS reset settings when entering the system -- clearing the CMOs and resetting without starting the system may be a door circuit.

Memory:

Diagnostic card display c1c6d3d4 -- memory problems

(1) bad memory stick

(2) memory power supply clock

(3) the rows and columns inserted into the memory are changed through a hop.

(4) data and address lines.

(5) Poor slot contact.

Other memory problems

Cpu read memory crashes.

Running large software crashes-insufficient memory.

After 98, the file name contains fewer characters.

Some graphics cards (motherboard integrated with graphics cards) Need to borrow memory for memory display, so the memory must be inserted in the first slot, 72-wire memory should be used together with two. Insert 1.3 or 2.4 slots.

Graphics card:

FF--C1--C3--C5--OB--OD, 2B, 31 (some do not show here, some jump to the keyboard 6f4e Stop Jump)

Not displayed:

Bad graphics card

Use different video cards in each of the PCI, ISA, and AGP slots to test whether all the slots in the PCI slot are short-circuited by the pins in the ISA slot, the resetting of all PCI/ISA slots comes from a reset signal. But the clock is independent .)

All peripheral functions are connected to the south bridge, because only the south bridge connects I/O

Integrated graphics card (VGA)

The color-to-ground resistance of r.g. B. B should be around 100 euro.

Three colors and lines, field synchronization, the signal from the North Bridge output by the side of the IC to VGA, if there is no IC through the exclusion, there is a discharge by the inductance to the VGA power supply, the inductance is connected with capacitor filtering.

If the above components are all good, the North Bridge is broken.

General lack of color, check the resistance can be found. On the screen, the black screen may be damaged or the North Bridge may be faulty.

Display sequence:

Graphics card materials

Display motherboard information, mainly obtained from BIOS

The CPU information is displayed. The locking frequency cannot be set as the superfrequency, And the superfrequency must be good for the fan.

CPU frequency error: 1. Jumper hop Error 2. The clock IC has problem 3. The frequency of the resistor and Capacitor in the circuit is incorrect.

Display memory:

First, re-insert the memory: memory itself is bad, memory slots are faulty, Data, addresses, and control lines are faulty.

Displays the IDE connection information.

IDE is rarely bad.

1. Hard Disk not found -- exclude hard disk half, signal line, Master/Slave jumper on hard disk -- locate hard disk in CMOS settings -- locate the problem on the motherboard -- check the resistance price if the resistance value is not correct one should be traced to the south bridge, in the middle, there are many obstacles, and the middle is broken. Some Optical drives and hard disks cannot be inserted into an IDE slot.

2. Wrong hard disk capacity-signal line and hard disk itself first excluded (first clear CMOS and then change signal line most OK)

1> If the resistance is normal, the Southern bridge is broken.

2> check the resistance to open or Short Circuit

6. Soft drive materials.

1) Eliminate FDD and signal line _ main board faults.

2) view the CMOS settings (do not use FDD for the CMOS settings and do not display the FDD information during detection. If there is no FDD, the FDD failure is displayed. If yes, the FDD is displayed)

3) Some FDD edge to south bridge (less) some edge to I/O (MOST) I/O is more bad, but the South Bridge is less bad.

7. keyboard information:

Change the keyboard.

Poor contact.

Voltage, clock, one signal line

Check related capacitance, discharge resistance, (discharge resistance power supply)

Check the inductance I/O, the South Bridge is rarely bad, and the keyboard port is easy to bad.

8. COM port

The comport is rarely bad, and the comport core is mostly bad. You can check the resistance value to find out the problem. I/O may be bad, but the South Bridge is rarely bad.

9. Print port (many faults)

Blocking power supply ___ print port _ (some pass through 330/220 blocking) I/O blocking 5 V power supply to each line, the first power supply line has capacitive filtering, most of which is I/O bad, the impedance capacitor is rarely broken.

10. USB port (with few faults ):

Check 5 V power supply.

USB is directly connected to the south bridge, only a few to I/O, and other related components are not easy to break. The keyboard, mouse, and inductance between USB and the south bridge I/O are easy to break, and the inductance plays an insurance role.

11. game ports

Some to I/O, generally to the South Bridge

Different I/O functions vary, depending on the number of I/o feet to check the power supply and wave capacitance-Good South Bridge is bad.

Sound Card/integrated sound card

Sound Card not installed: 1. CMOS Settings 2. No driver

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