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 Home » Repair PC's components » MOTHERBOARD REPAIRING STEPS

Easy steps for repair motherboard  

Repair parts
Do not turn fault detection method and sequence
1. Check the working conditions of the three CPU
l Power Supply
l clock
l Reset
2. Remove the BIOS chip select pin 22 check whether the signal transition
3. Test for BIOS, search the line connected with the BIOS
4. Charles ISA, PCI, on the data lines, address lines (and AD), interrupt and other control lines (this can be a direct reflection of north and south bridge problem)
5. Charles AGP, PCI, CPU Block North Bridge on the way to determine whether the normal resistance
l CPU core voltage power supply
2 FET bad, open or short circuit
2 short-circuit filter capacitor (electrolytic capacitor)
2, no output voltage IC
No 12V power supply
voltage IC bad
2 CPU voltage related to minor short circuit
2 bad of a field effect transistor, the output voltage becomes lower
2, no effect on the feedback circuit
2 Output voltage and low voltage IC
l VID 0-4, (+5 V voltage)
2, no output voltage IC
2 and the exclusion bad CPU Blocks
2 Break
l VTT 1.5V
2 bad power FET
2 VTT1.5V a right to short-circuit
2 FET power supply is not normal
2 FET bad
l clock
2 CPU Clock Tower and the open circuit between IC
2, no output clock IC
2 and output filter capacitor connected to the bad (10 PF)
2 power supply is normal 3.3V 2.8V 2.5V
2 All no output or no output half
2 from the crystal oscillator 22 is to determine if the bad skin
2 have electricity, IC bad
2, no power, check supply the relevant line
2 IC bad
2 half check for abnormal
l Reset
Low Voltage Reset 2: Bad Northbridge
2 There was no reset voltage
? North Bridge North Bridge without welding or reset false
? Disconnect the line connected with the North Bridge

2 are reset: continuous line with the North Bridge
2 No Reset: Reset generation circuit check

Boot display and related failures to judge
1. Display the information and memory card capacity
2. Shows the motherboard model, manufacture date, BIOS version of the content
3. Shows the main frequency of CPU, (FSB and multiplier)
1) CPU Block bad
2) Jumper Settings Error
3) North Bridge and CPU line between Block
4. Memory capacity
1) bad memory
2) bad memory slot
3) Northbridge bad
4) memory slots poor contact
5. IDE interface status
1) not detected
i. signal line and the hard disk, CD-ROM
ii. IDE Interface needle
iii. Southbridge bad break
2) detection of errors
i. hard drive, optical drive signal line
ii. IDE interface issues
iii. Southbridge bad
iv. Clear CMOS
6. Floppy
1) Setting error
2) signal line and the floppy drive
3) Floppy Interface
4) I / O bad
5) South Bridge bad
7. Keyboard, mouse
1) The keyboard, mouse, bad
2) The relevant line (exclusion, inclusion and exclusion, inductors, resistors, I / O)
3) keyboard lock (CMOS, keyboard lock-related lines)
4) South Bridge, or to break or short circuit between the South Bridge
8. Sound card
1) not detected
i. CMOS off (clear CMOS)
ii. sound card and crystal (no waveform voltage one high and one low)
iii. Supply (78L05)
2) noise
i. input power supply filter capacitor
ii. the output filter capacitor
iii. sound bad
iv. Southbridge bad
9. USB, COM ports, printer port, game port
1) interface bad
2) The power supply is not normal
3) signal line in question
4) I / O or the South Bridge

Memory-related failure to judge
1. Read less memory
? Slot bad
a) bad shrapnel Contact: oxidation, stretch out of control, open
b) short circuit burned out groove: two-pin short circuit, damaged
? Memory-related lines: one slot short circuit; power supply; clock; ranks gating; lines are open; data line; address line; control line; Northbridge bad (most of the relevant line with the North Bridge)
2. Digital jump incomplete
C0-C1-C3-C5 (no C3 and C5, are related to line problems)
3. Memory error
? Memory bad
? Access to good
? Slot problem with the line between the North Bridge
4. Into 98 missing characters: the bad memory
5. After the crash into the 98: the bad memory
6. AGP slot short circuit - effect Northbridge, RAM
7. BIOS error or data loss
? Virus infection
? Upgrade fails
? Power supply does not
Note: The clock IC are sometimes not read memory
Diagnosis of Different motherboards have different number of cards to go, often have the following three kinds:
2: FF-C1-1d-2b-3d-42-6F-7F-FF
3: FF-d3-d4-0b-2A-31-3d-4E
Sound Card Trouble
1. Power Supply
78L05 12V power outlet to the three-terminal regulator input pin, the output is 5V voltage to the IC card
2. IC card to work should be hot
1-12 feet which is more important, including the power supply, crystal oscillator, two feet, the control signal
3. Crystal
24.576MHz, next to two small capacitor 22PF
? Have a power waveform
? Into the 98 after a wave
? Only level, no wave, one high and one low voltage
4. PA
Just the sound card output audio signal amplification (amplifier sound bad cause little noise, no sound)
Failure of some of the problems caused by sound card
1. Power Supply
2. Crystal
3. Sound card chip
4. PA
5. Sound card and amplifier small capacitor around
6. CMOS setting error will cause silent, not the sound card installed
7. BIOS Bad


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