The Laptop Mainboard Maintenance Skills

Jan. 23, 2011 - PRLog -- The Laptop MotherBoard Maintenance Skills
14.318 MHZ and 32.768 KHZ whether adverse)
3-1-3. Check the few without PIN (JUMPER) whether to did not go up or go wrong
Position the voltage is correct, a few better 32.768 KHZ
Frequency and relevant lines are normal
3-2 cardin PCIRST is not correct
Check the PCI CHIP cluster generator attempts to PCIRST SLOT (PIN) of line is A15
OPEN or without adverse or parts
3-3 CPURST is not correct
Check to the CPU CHIP cluster generator attempts the line is OPEN or without adverse or parts
4. Check BE0 BE7, A2 ~ ~ ~ D63 D0 A31, such as signal and its relevant line is
OPEN or without adverse or parts
5 cardin check ADS, CPURDY, PCI REQ0 ~ REQ3, such as the signal and its relevant lines
Whether OPEN or without adverse or parts
6 cardin check AD0 ~ AD31 SLOT of PCI signals of related line is OPEN or
Without bad or parts
7 cardin BIOS bad or no material (can use good quality products of exchange test to determine the BIOS
8 cardin check SA16, SD0 SA0 ~ ~ ~ XD0 SD7 (XD7) signal and its relevant lines
Whether OPEN or without adverse or parts
1. Familiar with PC mainboard bus type and the I/O bus slots in each signal arrangement situation, with I/O slots in important signals for
Clues for fault point search is maintenance PC mainboard fatal fault of the key.
Laptop motherboard common bus with PC/XT, PC/mig-at, VESA, PCI type etc, different bus I/O trough of citic
Number permutation has a difference, familiar with I/O trough of important signals are searching for bus crash, fault system of screen no display etc strictly
Heavy fault of premise. To crash, first class fault distinguish fault reason is by an I/O device failure cause or motherboard itself so
Disabilities caused. Diagnose faults in the system board hind, can detect the system board I/O trough of the address bus or data bus pulse condition at the beginning
Step judgment system failure positions: if all the address bus or data bus are no pulse, likely is not working; CPU If a
Don't address bus or data bus at a constant level while remaining bits for pulse, is the bus fault. Due to the CPU itself the failure
Low, so check CPU without reason from the CPU input signal is normal working on. The basic work of the CPU
There are three conditions, namely system RESET signal RESET, system clock signal CLK, CPU READY signal comments. With PC/mig-at machine
For example, the CPU (intel286) 29 feet to RESET signal, corresponding to the I/O slot B02 slot DRV signal RESET, at boot
When should a prominent positive pulse, The CPU 31 feet for CLK signal, corresponding to the I/O slot B20 slot system clock SYSCLK signal
, should be TTL level of the clock pulse. The CPU 65 feet for comments signals, the boot for low level or pulse. A P
C/mig-at machine crash, screen show no fault, first check the I/O slot B02 slot DRV signal RESET for constant low, explain boot RESET
Wrong, then check the clock signal processing chip 82284-12 feet, at boot has a positive pulse, explain 82284 has correct sends
A system reset signal, tracking reset signal transmission path down that have been correctly 82284 check issued the system restoration
Signal, tracking reset signal transmission path down checking, discover 74ALS02 five, six feet input is positive, but the output pulse 4
Feet, but as "high and low" float level, replace the chip empty after troubleshooting. The bus breakdown maintenance principle is: if the hair
Now a certain one or a few at a constant level, can restart check these bits at boot instantly whether at a constant level,
If the boot instant namely at a constant level, is the error status, If the boot instantly pulse and then into a constant level should be first
Check the other signal, If discover the eight even more bits simultaneously error status, then should check whether the CPU is work
Often or corresponding bus driver door control signals.
2 I/O devices running abnormal failure analysis skills
An I/O device operation involving the I/O devices (such as printers, display, soft, hard disk) itself, the connecting cable,
Multi-function card or motherboard. In through the substitution and insertion method really accurate fault occurred in the mainboard, seize the motherboard relevant peripherals
Important control signal, and then the lsi chips function to understand somewhat cases is also easy to remove the faults. if
Floppy drive motor rotation indicator light but not reading the floppy drive. Seize DREQ2, HQR, HLDA, DACK2 several signal and transmission channel can be very
Fast fixed-point failure positions. In addition, the interrupt peripheral devices running plays a very important role, therefore, from interrupt controller and
Broken control signal transmission path search involves interruption peripherals malfunction is also must consider. The Laptop MotherBoard control circuit is
For complex, fortunately control functions of high concentration and transmission path simplified, want to hold important control signal to the mainboard failure
Positioning, faster than early to division element mainly fault locating faster.
3. Randomness breakdown maintenance skills
Randomness fault reason is relatively complex, chips or equipment with connectors way connecting systems exist contact undesirable,
Sequential control circuit sporadic time-series signal drift, Chip matching between the level in time sequence matching bad (such as some compatible
Machine memory chip reading speed inconsistent); Circuit wiring unreasonable or other reason makes the motherboard chip between pins produce
Capacitance inductance can cause randomness malfunction. Such fault performance in manifestation memory wrong, memory calibration error, keyboard input
Crash, literacy floppy disk, printing, etc when operating not fixed place randomness fault. Key from below circuit of signal
(1) the system control circuit, such as ALE address latch signal. (2) the system memory circuit: RAS, CAS ranks choose communication number,
ADDRSEL ranks address translation control signal, memory data read drive, memory chip speed matching relations. (3) system
The address bus and the data bus chip. (4) the system clock signal SYSCLK, various PCLK, DMACLK. Particular attention should be within
Save memory chips, speed matching relations and 74FXX, 74LSXX, 74ALSXX etc chip difference. Of course to randomness
Fault occurred phenomenon is fixed, but from phenomena directly judge fault reasons, such as host sometimes activation, sometimes don't start,
Once started after the system work completely normal and long regular, it is likely the "POWER" signal POWER - no
Normal caused.
4. Other categories of breakdown maintenance skills
(1) mainboards are burnt out. This is usually due to pulling insert system charged connector, or circuits of power between short
Road and cause, right now but adopt static resistance measurement method. If you find any input/output feet and power supply or to direct conduction (
Unless the original circuit such as in addition) belong to the breakdown fault; If you find two similar input feet or output feet resistance exists very bright
The significant difference, generally, is also fault. Note: on the mainboard burn-in breakdown maintenance not simple change burned-out yuan
Thing settles, but should check with the related many components, until the fault eliminate and trouble-free elements can add electrical measurement
Try.
(2) system configuration parameters is not correct.
Such fault can be generally by resetting system configuration parameters can, but if the configuration parameters cannot set or not
Can save system configuration parameters, then from batteries, CMOS RAM chips, CMOS RAM power supply circuit, and write circuits etc
Aspects lookup breakdown reason.

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