Laptop MotherBoard Repair Step One
1
Laptop MotherBoard Repair Step One
Table of Contents
Introduction………………………………………………………………………………………………………10
Important notice for your Safety…………………………………………………………………..11
Part 1
Tools and Testing Equipments
Types and Functions
Repair Tools to Troubleshoot Laptop……………………………………………………………13
Cleaning Tools…………………………………………………………………………………………………14
Screwdrivers Tools……………………………………………………………………………………………14
Soldering Tools…………………………………………………………………………………………………15
Bios I/O KBC Programmers………………………………………………………………………….……18
ESD Safe Tools……………………………………………………………………………………………….…19
Inspection Tools…………………………………………………………………………………………….…20
Electronic Measuring Tools……………………………………………………………………………….21
Laptop Battery Tester……………………………………………………………………………………….22
Gripping Tools………………………………………………………………………………………………..…23
Other Tools…………………………………………………………………………………………………….…23
Part 2
Laptop Parts Tour
Basic Laptop Hardware Tour…………………………………………………………………………..…26
Laptop Case………………………………………………………………………………………………………26
Motherboard………………………………………………………………………………………………….…27
RAM Memory Cover Door…………………………………………………………………………………27
DVD/CD-RW Driver……………………………………………………………………………………………28
Battery………………………………………………………………………………………………………………29
Power Adapter……………………………………………………………………………………………….…30
KeyBoard…………………………………………………………………………………………………………..31
Laptop Memory…………………………………………………………………………………………………31
Hard Driver……………………………………………………………………………………………………..…34
Touchpad/Trackpad…………………………………………………………………………………………..36
4
Laptop MotherBoard Repair Step One
Mouse Buttons………………………………………………………………………………………………….37
Laptop Screen……………………………………………………………………………………………………37
Screen Inverter…………………………………………………………………………………………….……39
Screen Cable………………………………………………………………………………………………..……39
Web Camera……………………………………………………………………………………………..………40
CPU Fan……………………………………………………………………………………………………….……40
CMOS Battery……………………………………………………………………………………………………41
CPU Central Processing Unit………………………………………………………………..……………42
LID Close Switch………………………………………………………………………………………..………42
Front Bezel……………………………………………………………………………………………………..…43
Cover-Lid with Wi-Fi Antenna……………………………………………………………………………43
Wi-Fi Cards……………………………………………………………………………………………….……….44
Hinges Rails…………………………………………………………………………………………………….…44
Hinge Covers……………………………………………………………………………………………………..45
SD Card Reader…………………………………………………………………………………………….……45
Power Button Board………………………………………………………………………………………….46
Other Hardware Parts……………………………………………………………….………………………46
Motherboard Overview…………………………………………………………………………………….47
Top 10 Youtube Channels Tech Laptop Disassembly…………………………………50
Part 3
Basic Electronics
What is Electricity? …………………………………………………………………………..………………52
What is an Electron? ………………………………………………………………………………………..52
Voltage Pushes Electrons………………………………………………………………………………….54
Current Flows……………………………………………………………………………………………………54
Resisstance Reduces Current…………………………………………………………………………….55
Types of Current……………………………………………………………………………………………….55
How do we Measure Electricity? ………………………………………………………………………57
Effective Resisstance…………………………………………………………………………………………59
Binary Number system………………………………………………………………………………………62
Bits and Bytes……………………………………………………………………………………………………63
Logical………………………………………………………………………………………………………….……64
Logic Gates……………………………………………………………………………………………………..…65
AND Gates Check for Tow True Input…………………………………………………………………66
OR Gates Check for One True Input……………………………………………………………………66
5
Laptop MotherBoard Repair Step One
Not Gates Flip Inputs…………………………………………………………………………………………67
A Bigger AND Gates……………………………………………………………………………………..……67
Part 4
Electronics Components
The Main Electronic Components in Laptop Motherboard……………………………………..70
Capacitor……………………………………………………………………………………………………..……71
Capacitors Testing…………………………………………………………………………………………..…81
Resistor…………………………………………………………………………………………………………..…84
Resistor Testing…………………………………………………………………………………………………89
Inductor – Coil…………………………………………………………………………………………………..96
Inductor Testing……………………………………………………………………………………………..…98
Fuse………………………………………………………………………………………………………………..…99
Fuse Testing………………………………………………………………………………………………………100
Diode………………………………………………………………………………………………………………..101
Diode Testing…………………………………………………………………………………………..……….104
Zener Diode………………………………………………………………………………………………………105
Testing Zener Diode……………………………………………………………………………………….…106
Transformer………………………………………………………………………………………………….....107
Crystal Oscillator…………………………………………………………………………………………….…108
Transistor………………………………………………………………………………………………………….110
Intergrated Circuit (IC) …………………………………………………………………………………..…126
The most important integrated circuits are in Laptop Mainboard…………..…………128
EEPROM……………………………………………………………………………………………………………129
Super I/O…………………………………………………………………………………………………………..133
Clock Generator…………………………………………………………………………………………………134
Voltage Regulator………………………………………………………………………………………………135
PWM Controller…………………………………………………………………………………………………138
Microprocessor……………………………………………………………………………………………….…140
Part 5
Identifying of Common Components of the Laptop Motherboard
Capacitors (C) …………………………………………………………………………………………………..142
Inductor – Coil (L) ……………………………………………………………………………………………..144
Fuse (F) …………………………………………………………………………………………………………….146
Diode (D) ………………………………………………………………………………………………….………147
6
Laptop MotherBoard Repair Step One
Zener Diode (ZD or PD) …………………………………………………………………………………….147
LED……………………………………………………………………………………………………………………148
Crystal (X or Y) ……………………………………………………………………………………………….…148
Resistors (R) ……………………………………………………………………………………………………..149
Mosfet (Q) ………………………………………………………………………………………………..……..150
Transistor (Q) ……………………………………………………………………………………………………151
Bios IC……………………………………………………………………………………………………………….151
FAN Connector………………………………………………………………………………………………….151
Bios…………………………………………………………………………………………………………………..152
Part6
Documents Related to the Laptop Motherboard
User Manual…………………………………………………………………………………………………..…154
Service Manual……………………………………………………………………………………………….…154
Schematic Diagram……………………………………………………………………………………………155
Block diagram……………………………………………………………………………………………………155
Datasheet……………………………………………………………………………………………………….…156
Part 7
How to Read Datasheet
How to Read DataSheet? ………………………………………………………………………………….158
Pin Configuration……………………………………………………………………………………………...159
Part 8
Motherboard Part Numbers
What is laptop ODM? ……………………………………………………………………………………….162
How to get the schematic diagram? ………………………………………………………………….163
Part 9
How to Read Laptop Schematic?
What’s the schematic diagram? …………………………………………………………………….…167
Important Part Schematic Diagram……………………………………………………………………167
Understanding Basic of Schematic…………………………………………………………………….170
4-1 Schematic Path and Connection Between Circuits………………………………..…….171
7
Laptop MotherBoard Repair Step One
4-2 Information…………………………………………………………………………………………………175
4-3 Finding signs………………………………………………………………………………..…….……….177
4-4 Related Search………………………………………………………………………………………......178
4-5 How to deal with schematics that don't have the power sequence……………..183
Part 10
Signal
Explanation of common signal names……………………………………………………………….188
Signals……………………………………………………………………………………………………………….188
The Power good signal………………………………………………………………………………..….…188
The open signal…………………………………………………………………………………………………190
Reset Signal……………………………………………………………………………………………………….191
+5VALW +3VALW signal………………………………………………………………………….…………192
PWR_S5_EN………………………………………………………………………………………………………192
Clock signal……………………………………………………………………………….………………………194
Chip Select Signal………………………………………………………………………………………………194
Part 11
The Architecture of the Laptop Motherboard
Power supply and signal……………………………………………………………………………………197
The AMD single bridge architecture (A70) ……………………………………………………..…198
The Nvidia architecture double bridge (C51M) …………………………………………………199
High-level and low-level signals…………………………………………………………………………201
The architecture of Nvidia single bridge (MCP67) ……………………………………………..204
Part 12
The Basic Knowledge You Must Know Before Starting to Repair Laptop
What is a short circuit? …………………………………………………………………………………….214
Finding a short……………………………………………………………………………………………….…215
What is a voltage divider? …………………………………………………………………………..……216
What are System Power STATES? …………………………………………………………………….218
What is a DC to DC boost circuit? ………………………………………………………………..…..219
What is a feedback?………………………………………………………………………………………….220
Diagnostic method for laptop power supply circuit failure………………………………..221
Laptop motherboard power supply…………………………………………………………………..222
Protection isolation circuit………………………………………………………………………………..222
Charging control circuit…………………………………………………………………………………….223
8
Laptop MotherBoard Repair Step One
standby circuit…………………………………………………………………………………………..………227
Analysis Linear Regulated Power Supply Type Standby Circuit…………………………..228
Switching power supply type standby circuit…………………………………………………....229
CPU circuit…………………………………………………………….........................................……233
CPU core power supply circuit………………………………………………………………….…….…236
Memory circuit………………………………………………………………………………………………….238
Part 13
Dictionary for Technicians
Name Components Code table………………………………………………………………………….238
The motherboard common signal definition………………………….………………………….238
SIO pin description……………………………………………………….…………………………………..238
Conclusion…………………………………………………………………………………………….………….238
9
Laptop MotherBoard Repair Step One
FAN - Heat Sink
CMOS battery
The CMOS battery connects directly to the laptop motherboard and helps to retain
important BIOS settings such as system time, date, BIOS configuration while the
laptop is turned off or even when the main battery is removed, the CMOS battery
is rechargeable and it’s getting charged when the laptop is plugged into the mains.
41
Laptop MotherBoard Repair Step One
48
North bridge
chip
AMD CPU
VGA Chip
RAM Slots
VGA Memory Chip
Memory Chip
CMOS Battery
South bridge
chip
VGA Memory Chip
Memory Chip
RAM Slots
VGA Chip
CPU Socket
Laptop MotherBoard Repair Step One
58
Power (P)
Voltage (V)
The total work
performed by a
current
Electrical force or
pressure
Current (I)
Resistance (R)
The number of
electrons passing
in a single point
Resistance to
the flow of
current
Laptop MotherBoard Repair Step One
68
We can also make a 4-input AND gate from three 2-input AND gates, like this:
4-input AND gate
A
B
Q
C
D
Laptop MotherBoard Repair Step One
4- Using Digital Multimeter
Using the Continuity test or the Buzzer mode
Testing SMD Ceramic Capacitor
1) Put the two ends of the measurement
on the ceramic capacitor.
2) Shows value without sound of a buzzer
so ceramic capacitor is Good.
1) Sound of a buzzer with 0 value so
capacitor is damage (short circuit)
83
Laptop MotherBoard Repair Step One
Resistor Testing
1- Visual inspection: Checks for missing or any burning on resistance.
Example of Burnt resistances
2- Using Digital Multimeter: You can check the resistor resistance by selecting the
ohm range in the digital multimeter, If the resistor is in circuit, you will generally
have to remove the resistor so you are testing only the resistor value and not the
other components in the circuit.
Set the dial to
resistance mode
89
Laptop MotherBoard Repair Step One
SMD diode use a line to mark which
pin is the cathode
Diode use a grey ring to mark
which pin is the cathode
Diode symbolized on mainboard and circuit diagramwith the
letter D
Diodes symbols on schematic diagram
Zener Diode
Schottky Diode
Silicon Diode
102
Laptop MotherBoard Repair Step One
Important Note: Transistors come in a variety of case styles. The pin-out for the
emitter, base, and collector is not the same from device to device. Likewise, it’s
impossible to determine if a transistor is a PNP or NPN type by it’s shape or case
design. Everything can be determined using the transistors part number. To get the
right pin-out, you will have to refer to a datasheet and look up the device using the part
number.
Another trick for common, low-power transistors, is to connect the ohmmeter to the
collector and emitter, leaving the base hanging open. Apply polarity so the collector
will be reverse biased (positive for NPN, negative for PNP.) Now wet a finger and
thumb. Hold the base and collector leads in this finger/thumb clamp (don't let them
touch). This injects some current into the base. If the ohmmeter resistance reading
decreases, the transistor is working. By holding the base and emitter leads between
thumb and finger, the resistance should go Up. These simple tests often tell if you have
a PNP or NPN transistor, and if it is good or bad.
If you have access to a transistor’s data sheet, then you already know a lot about the
transistor. You know whether it is NPN or PNP and which lead is the emitter, the base,
and the collector, However, the transistor's data sheet will show you that.
The first page is usually a summary of the part's function and features.
114
Laptop MotherBoard Repair Step One
136
Input voltage
VIN is the IC
power supply
input voltage
Output voltage used
to power chip on
DDR memory, this
voltage equal
VDDQSNS/2
Voltage regulator G2997 Pin Description
Pin 10 is (VIN) voltage input of IC for work, powered by 5V
PIN 1 is (VDDQSNS) input voltage, equal value of DRR3 RAM (1.5V)
PIN 3 is (VTT) This pin is used to the voltage regulator output. VTT value It will be
equal VDDQSNS/2, here we have 1.5/2 = 0.75v, its responsible for supply chips
located on RAM.
Laptop MotherBoard Repair Step One
149
Resistors (R):
A Resistor
A Resistor Network
A fuse resistor
Resistor value
Resistor Symbol
NTC thermistors Symbol
Location Marking
Negative Temperature Coefficient (NTC thermistors) are resistors with a negative
temperature coefficient, which means that the resistance decreases with
increasing temperature. They are primarily used as resistive temperature sensors
and current-limiting devices.
Laptop MotherBoard Repair Step One
Sony
SONY MBX-123
Asus
Wistron
ASUS EEEPC P701
Wistron JE40 HR – 48IQ01.031
Quanta is probably the biggest laptop manufacturer, followed by Compal and
Pegatron. Compal and Pegatron probably have the best quality overall.
Information about the manufacturer and motherboard model laptop very
important to us. you might need to know model number motherboard’s model for
a number of reasons as stated below:
1- Looking for motherboard BIOS file or the need to update the BIOS of
motherboard
2- Looking for a motherboard schematic.
3- Need to update the drivers of hardware as audio drivers.
How to get the schematic diagram?
The easiest way to look for the schematic diagram in the internet is by using the
laptop reference, for example: Acer Aspire 1300, Hp pavilion DV5-1000us etc.
In case you don't find the schematic using the laptop reference you can use the
ODM.
To look for the motherboard schematic using the ODM method look for a
reference printed in the motherboard and use it to search for the schematic, below
is an example of those references for ODMs:
Find the motherboard model number
This is usually printed on the motherboard, but can be located in several possible
locations; for example, it may be printed near the RAM slots, near the CPU socket,
or between the PCI slots. There will be a lot of writing on the motherboard, but the
model number is usually written in the largest text (Motherboard model numbers
are typically a collection of numbers and letters).
163
Laptop MotherBoard Repair Step One
Below is another example of the change of names of the signals (or voltages) after
passing through certain component.
This is important for when we are reviewing the schematic and need to know
where certain voltage is generated. That is, when we have a missing voltage on the
motherboard and we need to find the source of this tension in the diagram.
Another important detail are the symbols shown next to the component
references.
The image above, we see that the capacitor C357 has the @ symbol (At) next to
your reference. This indicates that the capacitor is optional and will depend on the
card manufacturer if this component will be mounted on the board or not.
We can find some variants of this symbol as an asterisk (*), registration OPTION
and others. The important thing is to always keep in mind that if any component
has a symbol next to their reference in the schematic, it is optional and cannot
exist on the motherboard. See an example of another schematic:
174
Laptop MotherBoard Repair Step One
As mentioned above, sometimes the SIO sends a signal to the operation of the
sources of 3.3 and 5V. This circuit is on page 44 of our schematic.
Being in this schematic page and searching for the number 38, we see that two
signals have direct communication with the SIO.
181
Laptop MotherBoard Repair Step One
189
The common abbreviations of PG signal are among others:
PD
VTTPWRGD
PWRGDx
CPUPWRGD
POKx
POK
PWRG
SPOK
Example:
After RT8205 gets all the needed voltages, then it will send SPOK like you see on
the next picture.
Some common Wistron signal names used around the charger chip MAX8725.
AD+: the first voltage that the adapter converts.
DCBATOUT: common point of the 19V.
ACOK: the adapter detection output for charging chip.
DCIN: power supply input for charging chip.
ACIN: adapter detection input for charging chip.
Check next picture.
Laptop MotherBoard Repair Step One
Chip select signal is common in BIOS chip, noted as CS#, and "#" means that it is
active when it is low. It's sent by CPU from the North Bridge to the South Bridge &
finally to the BIOS.
It exists or not, which can initially judge whether the North & South Bridge and
CPU work, and whether BIOS information is destroyed/corrupted.
SPI BIOS pin shown in next image, CS# is the BIOS chip select signal.
195
Laptop MotherBoard Repair Step One
The GND or the ground is used to close the circuit power loop. Because without
GND no current will flow through the device in question. The symbols used for the
ground are VSS or GND.
The North bridge and South Bridge are connected by the so-called Hub-Link that
later is named to DMI (Direct Media Interface). The speed of this connection is very
fast.
The South bridge controls mainly the next devices:
1- USB devices like camera, blue tooth and card readers etc.
2- Audio card. Modem and audio are on the same line
3- SATA: Hard disk and CD-ROM/DVD-ROM
4- IDE: early hard disk and CD-ROM/DVD-ROM
5- PCI-E device: Network card and card reader, expansion card, mini PCI-E slot etc.
6- EC which is connected by LPC (low pin count got his name because it is one of
the busses that has small number pin-out).
202
Laptop MotherBoard Repair Step One
Finding a short:
Here we have four capacitors on this line. The line works great!
Until one day, water is spilled and a capacitor explodes. PC51 is now sending all the
voltage to ground!
Measure each capacitor, right?
- Many will turn their multimeter to capacitance or resistance mode and
measure PC51 is the bad capacitor. Let’s assume PC55, PC54 and PC50 are
working in perfect condition.
- We take the multimeter and place black probe on pin 1 of PC55 and red
probe each capacitor.
This will not work! Can you guess why?
- be on pin 2 of PC55.
215
Laptop MotherBoard Repair Step One
Diagnostic method for laptop power supply circuit failure
The motherboard power supply circuit of the laptop computer is an indispensable
part of the laptop computer and its problems usually lead to various failure
phenomena such as failure to boot, automatic restart, and crash etc.
To learn the diagnosis and elimination of the fault of the power supply circuit of
the laptop motherboard:
firstly, the basic working principle should be mastered.
Secondly, the common fault phenomena caused by the problem of the power
supply circuit of the motherboard should be understood.
Finally, the maintenance experience of the power supply circuit of the
motherboard should be continuously summarized and learned. method.
1- Laptop motherboard power supply circuit basics There are two ways to supply
power to the laptop motherboard. One is the dedicated rechargeable battery
for laptop computers and the other is to convert 220V mains to 19,5 or 20 volts.
Powered by the power adapter. The laptop's dedicated rechargeable battery
typically provides a lower supply voltage than the power adapter's input supply
voltage.
Whether it is a dedicated rechargeable battery or a power adapter for a laptop
computer, the power input to the laptop's motherboard cannot be directly used
by all chips, circuits, and hardware devices. This is because the functional
modules and hardware devices on the laptop motherboard. The current and
voltage requirements are different and must be converted after the
corresponding power supply.
Therefore, various power conversion circuits on the laptop motherboard have
become an indispensable part of the laptop computer. At the same time, after
the problem occurs in the power supply circuit of the laptop computer, it will
lead to various failure phenomena such as failure to boot, automatic restart,
and crash.
To learn the diagnosis and troubleshooting methods for the power supply
circuit of the laptop motherboard, you must first master the working principle
and common fault phenomena, so that the fault analysis can be reasonable and
the troubleshooting can be quickly and accurately performed during the
maintenance of the notebook computer.
221
Laptop MotherBoard Repair Step One
As shown in Figure 7a, the +CPU CORE supply powers the core of the CPU,
which is typically provided by a CPU power supply circuit located near the CPU
socket of the motherboard.
As shown in Figure 7b, the +GFX CORE power supply is the power supply for the
integrated display core in the CPU. This power supply is also typically provided
by an independent switching regulator power supply circuit.
As shown in Figure 7. The CPU is connected to the ground circuit. For a CPU
with high power consumption, a large number of grounding wires can
effectively ensure the safety and stability of the CPU. As can be seen from
Figure 7, the CPU needs voltage when it works normally. A variety of power
supplies with different currents can ensure that the functional modules
integrated in the CPU work stably. The various power supplies required by the
CPU are provided by a dedicated switching regulator power supply circuit, and
some are converted by other power supply circuits. Several important CPU
power supply circuits are specifically described below.
1.5 CPU core power supply circuit
The CPU core power supply circuit provides a core power supply circuit for the
CPU of the laptop computer, and is a switching power supply circuit, which is
usually composed of a power control chip, a field effect transistor, an inductor,
a capacitor, and a resistor, and the like, wherein the power control chip It is the
core of the circuit, not only has the function of driving and controlling the
circuit, but also the functions of detection, monitoring and protection.
The power control chip can monitor the voltage and current changes of the
output of the power supply circuit through the circuit connection of the
relevant pins, thereby ensuring the stability of the current and voltage supplied
to the CPU. When the power supply circuit is abnormal, the power control chip
can turn off the circuit output, thereby protecting the entire circuit and the
CPU.
The power control chip outputs a control signal through the relevant pin to
control the on and off of the FET in the circuit, thereby converting the power
provided by the upper power supply circuit into the core power supply of the
CPU.
The difference from the fixed voltage output power supply circuit is that the
voltage value of the CPU core power supply is dynamically changed. This
requires that the power supply control chip in the CPU core power supply
circuit should first understand the power supply voltage required by the CPU,
and then drive the power supply.
236
Laptop MotherBoard Repair Step One
Recommended training to Learn laptop motherboard Repair
The information below will help you learn how to repair your laptop motherboard
successfully. Click on photo below to visit the website:
Please visit the Resources Page to get more useful repairing information at:
http://eloy-motherboards.blogspot.com/p/newsletter.html
249