Motherboard does not boot repair methods

会员1115209

Motherboard does not boot repair method ( not boot failure is expressed as: power switch does not work).
1. PCB for physical damage
2. Whether the scorch marks
3. Whether the leakage capacitance, drum kits, loosening
4. Notice to see if there was been welded on the motherboard PCB interface within
5. Are there negative short Notice to see if there had been welded on the body OK
6, Measuring CMOS jumper cap if there is 3V, the absence of 3V ( INTEL original board and part of the brand board no voltage is normal), remove the cap and then jump to check whether there is a first pin 3V
A. Non- 3V, double check diode over VCCRST is normal ( the IO short circuit);
B. Have 3V , check Southbridge RTCRST # short circuit, a capacitor for leaked
7, Measuring
32.768KHZ is normal, (the NVIDIA motherboard also need measure to 25M crystal 1.6V or so.)
Check one: use the oscilloscope to measure crystal feet if there32.768KHz waveforms and frequency
Check Method Two: Use the multimeter to measure whether the voltage crystal feet, under normal circumstances, crystal feet have pressure ( INTEL, the AMD :0.1 ~ ~ 0.5V, NV 1 ~ ~ 1.6 or so)
A, If no voltage: check the RTCRST #, VCCRTC, playing with the crystal pin short circuit or open circuit, the dissolution of the resonant capacitor, for Southbridge.
B, If no pressure feet, substitution method (first for the crystal, and back to the resonant capacitor, resistor), and finally Southbridge.
C, Internal voltage if the crystal feet above the normal range, first for capacitance resistors, crystal, and then replanted Southbridge, not back to Southbridge.
D, If the hand can touch the crystal is energized to change the crystal, the resonant capacitors, resistors, and then replanted Southbridge, Southbridge last replacement.
G, the NVIDIA motherboard 25M is not normal, if the standby voltage is normal, the problem is the bridge.
8, check 3VSB normal
Check one: use the diagnostic card standby is lit.
Check Method Two: Measurement PCI slot A14 foot or PCI_E slot B10 whether feet 3.3Vvoltage (if there is no voltage, the first power play value is shorted to ground, short circuit first demolition of the card, and then split the South Bridge Road continue Charles 3VSB conversion source voltage, then the next step maintenance.)
9, The measurement RSMRST #hether 3.3V
Measuring point: Check the IO chip pin, check drawings or demolition Southbridge run line, pay attention to the different chipset name is not the same, can also skip this step. If RSMRST #voltage is 0V , check the signal generating chip standby power supply , replace the chip, and finally Southbridge.
10, A common trigger circuit Maintenance ideas:
A, Measuring whether the switch pin is high, if not high, check the switch on the pull-up resistors, capacitors, the IO bad.
B, Measuring IO trigger if feet jump, if the switch pin is high, but the switch is pressed IO trigger feet without hopping, check switch to IO trigger foot line (running line)
C, If you press the switch on the front PWRBTN # no signal pin3.3V , first check the IO power supply and replace the IO back to Southbridge.
D, If the switch is pressed PWRBTN #signal transitions feet are not always 3.3V , the IO without power or IO bad.
E, If the switch is pressed SPL_S3 # signal pin is still low, the first measurement of whether its signal shorted, then check Southbridge standby condition.
F, If the previous trigger signal pins, PWRBTN #, SPL_S3 #normal jump up, PSON #signal pin is still high, the IO bad.
G, if PSON #signal pin is low, the green line is still high, the signal pin to the Green Line break
H, If you press the switch, the green line goes low jump, but still no power, that is, the power protection.
11, Automatic Power: Symptom expressed as plugged in is automatically powered up ( INTEL original board and DELL board automatically energized normal)
Maintenance: A, Continuous short circuit power pin 4 seconds if off, you can ignore this failure, usually because they were cleared CMOS automatic power was caused.
B, Sustained short power pin 4seconds or more can not be shut down, try to replace the parts connected to the green line, but note there are not included motherboard CPU or non- CPU power supply may not be able to shut down.
12, Power protection: Trigger after power off, commonly known as power-down (after 775 yards and ran the board is powered down, then automatically energized to continue to run the code belongs to normal).Power protection into power protection and board protection .
Power failure protection is triggered after the performance of power, the green line is low .
Maintenance: Maintenance of power protection board must first unplug the CPU power supply 12V small power supply, and then see if there is a power protection.
A. Not protected - turn on CPU power tube removal, power / driver chips, a large filter capacitor.(Quickly determined which field pipe bad: a pen then 12V, respectively, took another lead pipe D pole if this field through the bad .
B. Protection - master interface 12V / 3.3V / 5V short circuit
13, Motherboard protection: Motherboard Protection Faults as triggered off, the green line is high (can be triggered again)
Maintenance: cause the motherboard to protect common following.
A. the RTCRST # low (CMOS jumper jump trans);
B. H61 motherboard flashed BOIS above information;
C. Missing power supply (power supply or instant measurement energizing force measured for each power supply is normal);
D. Check power ok voltage pin, part of ITE IO board code will not run off, you only need to repair the fault code can not run (ASUS AM2 board majority);
E. The NVIDIA chipset air welding (pressure bridge);
F. Southbridge THERMTRIP # is low the (over-temperature protection, to investigate the drawing);
G. Dual power can not switch (momentary power failure, 3VSB standby voltage change).

会员14822

这个应该是国外友人发的吧.全是看不懂..

会员494089

论坛欢迎外国朋友 希望分析更多维修资料