Thursday, April 23, 2015

Laptop Computer Electronic Circuit Literature

The purpose of electronic circuits is to control the flow of electric currents, it has been found experimentally that the intensity of various electrical effects is related to the amount of the charge that passes by a certain region per unit time. By controlling this amount we can vary the intensity of these effects. That's why this quantity , which is called the current, presents a special interest in engineering.
In practice, the flow of the current can be controlled by various electronic components. A network of interconnected components that can accomplish a certain task is referred to as electronic circuit.
The current can be measured by an ammeter. A voltmeter can be just an ammeter with a series-connected high-value resistor through which the current proportional to the measured voltage is forced to flow.
Impedance by definition is the ratio of the voltage to the current. Components in a circuit can be connected in series or in parallel With series connection, the same current flows through all elements and impedances add up. With parallel connection the same voltage is applied to all elements and conductances add up. In both cases the location of any element in the chain does not matter
Every circuit design starts with the development of a schematic. A schematic diagram is a drawing where components are represented by graphical symbols and that can communicate information about a circuit.
Before starting to find the problem on the motherboard we will try to implement the symbol and layout components contained / schematic diagram depicted on the motherboard, so we understand where the portion referred to in the diagram on the motherboard. This tutorial should turn you into a fully literate schematic reader! We’ll go over all of the fundamental schematic symbols:
Understand the electronic language. There will be a variety of schematic symbols on the schematic that represent real world devices and wires. A basic understanding of these symbols is required to read a schematic.
Understand ground. Ground is represented by either a triangle pointing down or a set of parallel lines that become shorter as they appear below each other, in effect representing the inner area of the triangle pointing down. Ground is a common reference point that schematics use to show the overall unity of the various functions of the circuit. It does not refer to the actual ground of the earth.
A line represents a wire. Wires are used to connect the devices together. All points along the wire are identical and connected. Wires may cross each other on a schematic, but that does not necessarily mean that they connect. If they do not connect, one will be shown looping around the other in a semicircle. If they do connect, they will cross and a dot will be seen at the point where the lines cross.
Resistor is represented by a zigzag shape. Resistors act to impede the flow of the circuit to an extent determined by the resistance value used. They are used to scale and shape the signal.
The voltage drop across a resistor is equal to the current flowing through it times the value of the resistor (V=IR). This allows the classic use of resistor to divide down a voltage. If a voltage source is applied to two consecutive resistors of the same value, the voltage created at the point between the two resistors will be half of the original voltage applied.
Capacitors are represented by two parallel lines. Capacitors are used to condition rapidly changing signals, as opposed to the static or slower changing signals that are conditioned by resistors. The traditional use of capacitors in modern circuits is to draw noise, which is inherently a rapidly changing signal, away from the signal of interest and drain it away to ground.
The non standard symbols will be of a geometric shape, usually a rectangle, with a device indicator number in or beside the shape. The indicator number should be Uxx. Wherever a wire contacts the device, there will be a number indicated at the connection point. This number is the pin number of the device.
Electronic devices are normally assembled on printed circuit boards (PCBs) that mechanically support and electrically interconnect parts by using conductive traces, etched from copper sheets laminated onto an isolating substrate. The size of the traces is calculated based on their current-carrying capacity and acceptable impedance.
Make sure printed circuit board code number recognized to get same number of schematic diagram applied .
This a ling of sample PCB code number:
Electric current is the number of electrons (electric charge) that flows through a point in the electrical circuit per unit time. electric current flows from the positive pole to the negative pole, it is because the positive pole has a higher potential than the negative pole.
Voltage is a potential difference that difference is the number of electrons in a material. On the one hand there are electrons accumulate material while on the other side there is the number of electrons were slightly. This is due to the magnetic force affecting the material. In other words, the material into an electric voltage. The magnitude of the effect of the electric current depends on the magnitude of the difference of electrons collected in a material (potential difference) .
Schematics are the maps that provide guidance on the assembly and functioning of an electronic circuit. Without a schematic, only an undocumented mass of devices and wires would be presented to the user or designer. A schematic allows the user or designer to understand the circuit function and become familiar with how the desired effect of the electronic circuit is achieved.. When we open the schematic , we will find the contents of the index circuit components, directions and connections between components, the manufacturer's standard voltage, power sequences ,voltage rail to enhance their production and new problems are known at the time the product is already in the market.
At the beginning of the index page describes the details of the pages on the circuit that allows us to look for problem areas happened on the motherboard.
Names and Values
Values help define exactly what a component is. For schematic components like resistors, capacitors, and inductors the value tells us how many ohms, farads, or henries they have. For other components, like integrated circuits, the value may just be the name of the chip. Crystals might list their oscillating frequency as their value. Basically, the value of a schematic component calls out its most important characteristic.
Component names are usually a combination of one or two letters and a number. The letter part of the name identifies the type of component – R’s for resistors, C’s for capacitors, U’s for integrated circuits, etc. Each component name on a schematic should be unique; if you have multiple resistors in a circuit, for example, they should be named R1, R2, R3, etc. Component names help us reference specific points in schematics.
The prefixes of names are pretty well standardized. For some components, like resistors, the prefix is just the first letter of the component. Other name prefixes are not so literal; inductors, for example, are L’s (because current has already taken I [but it starts with a C…electronics is a silly place]). Here’s a quick table of common components and their name prefixes:
Identify Blocks
Truly expansive schematics should be split into functional blocks. There might be a section for power input and voltage regulation, or a microcontroller section, or a section devoted to connectors. Try recognizing which sections are which, and following the flow of circuit from input to output. Really good schematic designers might even lay the circuit out like a book, inputs on the left side, outputs on the right.
The composition of the layout of the diagram are arranged horizontally, so it will look a little different to that of the actual motherboard on hand .dimension can be referred to in the diagram components side by side, it was in fact located on the opposite, or being away from that we need pay attention to the same component layout code in the diagram and the motherboard in order to understand the components in question by the diagram
Here we will look at the illustrations, how do I find the layout of the components based on the location code, symbols, components and circuit line either as a power supply or data interface.
If the problem refers to the power module then we can assume that the ic / chip related to power problems. there are a lot of ic / chips on the motherboard power supply support ,that is also called the power modul. Knowing the circuit groups and chip power source supply,we have narrowed down the search area problematic components. voltage and resistance information mentioned .
components in the page described the relationship between components and voltage standards requested by the motherboard to run normally. do measurements on components, if we find there is one component that does not emit voltage or does not meet the demand in the schema, then we assume that the component is faulty / short or broken. do the replacement and re-do the measurement.
Follow this simple Voltage flow on VALW section to requirement Power supply needs on General Laptop Motherboard...
commond problem of missing ADP Voltage due over voltage protection:
ADP+ source for SMPS 3 and 5 V system :
Input Source for TPS 51125 :
How SMPS dc/dc work with N Chanel Mosfet to get 3V and 5V :
General Laptop Power Supply diagram (VALW section of ADP+,+3V,+5V) as a Voltage requierment circuit to life :
To get more understand look at the sample power sequences here :
and here :
sample of motherboard design circuit here :
VS is the voltage that appears after swicht on.This section activate after S5_ON ,EC and bios chip powered well and surely both firmware working.
This is General power system needs to running for all VS power rail
Laptop requirements in order to switch on first are the availability of 3V and 5VALW. Careful when finding 5VALW missing , switched on first cause of several motherboard, 5VALW appear after switch on .Than 3V_ALW or 3VPCU provide power supply to the EC , BIOS IC , South Bridge ( SB ) , clock generator and oscylator on ALW voltage .
VSB or swuitch voltage button (3.3V) will appear after Bios and EC powered. some of laptop motherboard will found 17V switch voltage on one of pin switch button but after switch -on voltage is changed to be 3.3 V.This is normal. Press power button ( short to ground ) then 3.3VSB will turn into 0V and back to 3.3V.and if standby VSB 17V press power button VSB become 0V and back to 3.3V. than power button is a good sign . steps further is the signal being sent to the EC ( Embedded controller NPCE 885LAODX ) signal names is NBSWON # most other brands of EC signal name may SW_ON, EC_ON or whatever name of the signal as long as signal coming from SW1 sent to EC , this voltage must respond in the same manner of testing power button , BIOS IC and firmware connected to SPI interface to the EC .Signal confirmation to ensure EC BIOS working properly is RSMRST # for3.3V.RSMRST# signal sometimes appear after switch on and other motherboard without switch on 3.3 V already present .Modern Motherboard has 2 or 3 IC BIOS. Identified EC BIOS which is usually one-page schema with EC names EC BIOS.
Other important signal from EC is DNBSWON # ,this is PWR_BTN signal to switch on South bridge sent by the EC after receiving NBSWON # signal from power button . DNBSWON # 3.3V must be present otherwise it would not switch on , after this signal appears then the SB will sent SUSCLK # signal back to the EC and turn on VS as trigger for all switching gate driver as VR_ON , Suson , MAINON , S5_ON or SLP_S3 , SLP_S4 and SLP_S5 . and for all the Vs voltage to the Device .
How switching system work on Laptop motherboard :
How switching signal work with EC and Southbridge and measuring point to get know if there are missing voltage and enable signal :
VS voltage magnitudes can be seen in the schema motherboard in question (VS voltage rail).
VS for Strap Boot device:
1.Procesor (VCCORE) rail voltage 0.9 V-1.5V
2.Ram (VCCRAM) Voltage 1.8V rail for DDR2, DDR3 VTT 1.5 V to 08V-0, 99V
3.Vga chips and input / output control, hub chip (VCCP) 1.5v rail voltage, 1.8 V, 3v
VS to Device (Lcd / led, hdd, optical, usb, wifi, bloutooth, keyboard, sound, camera etc.) For details on each Rail Voltage VS can be seen in the schema and Datasheet motherboard and components as well as the device in question.
Signal the wave triger / Sensor / 2-way confirmation signal / data interface
signal function open / close gate charge of organizing stages enable / disable each component or PCI (Peripheral commucition interface). Microcontroller System signal is governed by where the manufacturer has made a firmware binary command to set logic gate interface and low count pin into each IC bios on each motherboard.
Differences sircuit and arrangement on the motherboard of course require different settings Microcontroller, so that each of each different motherboard brand and series firmaware will necessarily require different settings.
This system can accept input signal, process it and deliver the output signal in accordance with the program in the contents into it.Microcontroller input signal derived from the sensor information from the environment (discrete) while the output signal addressed to the actuator (an electronic circuit for moving or controlling a mechanism or system) then give effect to the environment.
The microcontroller can easily analogized as the brain of a device / product that is programmed to be able to interact with the surrounding environment, embedded system is often referred to as the control systems that are embedded in a product.
Embedded System can not stand Alone
Microcontroller need to trigger the CPU clock oscillator working on one instruction to the next instruction in microcontroller operation time of one or several clock cycles to run.
There are several types of memory found in the microcontroller, ROM (ReadOnly Memory) and RAM (Random Access Memory). ROM is used as storage firmware while in modern electronic circuit use type EPROM (Erasable Programmable Read Only Memory) and EEPROM (Electrical Erasable Programmable Read Only Memory). CPU, memory, clock oscillator, and I / O are in one integrated circuit. If some elements omitted, then the system can not work.
Unlike the simple Embedded controller, microcontroller on sircuit LaptopMotherboard more complex embedded systems which have an external rom called the BIOS IC separate even they actually are part inseparable
Microcontroller is a microprocessor system SET contained in a chip. Contains components of the system supporting the microprocessor, memory and interface provider (interface) Input output controller, the difference with the microprocessor usually only contains the CPU alone. (Except Sandybridge CPU).
Significant difference between microprocessor and microcontroller is, a microprocessor CPU (Central Processing Unit) with no memory and I / O support, while the microcontroller consists of a CPU, memory, I / O specific and supporting units, for example Analogto Digital Converter (ADC) that have been integrated in the microcontroller.
This system can accept input signal, process it and deliver the output signal in accordance with the program in the contents into it.
Microcontroller input signal derived from the sensor information from the environment (discrete) while the output signal addressed to the actuator (an electronic circuit for moving or controlling a mechanism or system) then give effect to the environment.
Easily the microcontroller can be analogized as the brain of a device / product that is programmed to be able to interact with the surrounding environment, as prescribed by the microcontroller .The system is often referred to as embeddedsystem control systems that are embedded in a product.
Bios chip as firmware storage to run microcontroller
Modern Laptop circuit have 2 Bios Chip to stored saparated Embedded controler firmware and PCH (southbridge) Firmware .
EC Bios rom size usualy smaler than Main Bios,This Bios chip stored a firmware to run microcontroler on Embedded controler (SIO) this firmware controlling Power management including switching system and Sleep state .
Embedded controler is a computer inside the chip ,to get runing this EC need firmware that we call EC bios file (firmware).Signal confirmation power OK name RSMRST.
See the diagram below to get more detil :
Main Bios is a firmware to run Southbridge most main function are running LPC Bus interface.
with the programming commands that are already regulated by inter-IO interface available with programming sircuit The difference arrangement will cause the system to malfunction.The storage capacity of the ROM is also much larger so that programming is more detailed and complex to do.
and How Main Bios connected to PCH here :
Knowing Bios Chip and how they work on this link :
Bios Chip reprograme with bios programer here :
Service log is made by technicians to make a record of faulty motherboard electricity and signal system , every single voltage and signal measurement are notice in this log .To narrow the search of missing voltage and signal, divide by checking symptom of faulty to be :
1.Dead motherboard
no led indicator at all, no fan moving ,no power .This motherboard require an adapter voltage (12V_15V_16V_18.5V_19V_20V) also 3V and 5V to completely VALW power in this link :
How use PSU to find shorted componen on circuit on this link :
How to found shorted component here :
First thing to do is Power Drain ,remove battery pack,with out power adapter push Power switch button for 30~50 second to realist EMI inductions .get the power try to boot up again.
If still no response ,follow stepping procedure below :...
Intermittent in electronic repair definition means sometimes equipment will work and sometimes not . Intermittent problems can occur in any conductor and in every electronic circuit . If you found error ( for example , sometimes display sometimes not ) Laptop work properly throughout the day without any problems and can last for a day and did not have a chance to see the error .
See the detil how to found and fix intermitten foult here :
Ready to practice ...?
Get schematic colection here :
Minimum Tools that a Profesional technician need here :
Major Laptop motherboard component here :
Overal General motherboard working system here :
How to make service log by following the symptom :
Beside using a multitester to measure Voltage rails need ,we also using Regulater Power Supply to monitoring current usage on no display issues.Event they have variation amount of current usage we could identified however Southbridge already runing on specific current usage .
The Southbridge is an integrated circuit on the motherboard that is responsible for the hard drive controller, I/O controller and integrated hardware such as sound card, video card if present on the motherboard, USB, PCI, ISA, IDE, BIOS, and Ethernet. The southbridge gets its name for commonly being South of the PCI bus. The southbridge is one of the two chips in the core logic chipset on a personal computer (PC) motherboard, the other being the northbridge. The southbridge typically implements the slower capabilities of the motherboard in a northbridge/southbridge chipset computer architecture
For more detil check the shoutbridge link on this page :…
Hand shake bettwen CPU-SB and clock generator on this link :
SB Power Button Timing
see how EC powering SB by sending pwr_on signal here:…
The SB controls the system reset signal timings, which are provided in this section.
ROMRST# is used for resetting the LPC system ROM. The SB generates ROMRST# and
controls the required timing for this signal. Depending on the system configuration, the timing of
ROMRST# may be referenced to RSMRST# or A_RST#. Enabling the Embedded Controller
(EC) will force the SB to deassert ROMRST# with respect to RSMRST#. This allows the EC to
access the ROM before the system access cycle begins.
The ROMRST# timing is shown with respect to RSMRST# and A_RST#
indicates the timing value that are applicable to each platform configuration.
see how S3_S5 runing on EC after SUSB and SUSC sent back to EC here :
Hand shake beetwen Clk_Gen with CPU and ICH
operates at a very small current. Care must be taken when working with this circuit.
To ensure the accuracy of the ICH/PCH RTC circuit for each specific board design and
RTC circuit layout, the external load capacitance should be optimized by choosing
correct values of the tuning fork capacitors C1/C2.
The occurrence of time-loss under environmental stress conditions is dependent on
motherboard factors (cleanliness, discrete component characteristics, layout, fork
capacitor values), and condensation. If time-loss is observed on your system, check all
of the sources of inaccuracy listed in this document to improve immunity of the internal
ICH/PCH oscillator to time loss.
Functional Block RTC
Real Time Clock
The Real Time Clock (RTC) updates the computer’s time and generates interrupts for periodic
events and pre-set alarm. The RTC also makes hardware leap year corrections. The SB’s RTC
includes a 256-byte CMOS RAM, which is used to store the configuration of a computer such as
the number and type of disk drive, graphics adapter, base memory, checksum value, etc.
Functional Blocks of RTC
The internal RTC is made of two parts—one part is an analog circuit, powered by a battery
VBAT, and the other is a digital circuit, powered by a main power VDD. Figure 1show the
block diagram of the internal RTC. The SB has added hardware-based daylight saving feature
and makes adjustments (spring forward or fall back) at the designated dates/times.
Both the dateand hour for the daylight and standard time are fully programmable, allowing for differentdaylight saving dates and hours for different parts of the world.
operates at a very small current. Care must be taken when working with this circuit.
To ensure the accuracy of the ICH/PCH RTC circuit for each specific board design and
RTC circuit layout, the external load capacitance should be optimized by choosing
correct values of the tuning fork capacitors C1/C2.
The occurrence of time-loss under environmental stress conditions is dependent on
motherboard factors (cleanliness, discrete component characteristics, layout, fork
capacitor values), and condensation. If time-loss is observed on your system, check all
of the sources of inaccuracy listed in this document to improve immunity of the internal
ICH/PCH oscillator to time loss.
see more detil about RTC on intel here :
Reballing is a process when we lift off the defective chip and repair it by applying lead based solder on the chip and placing it back on the board or replacing the component with a new one while also applying lead based solder on it before soldering it back on the circuit board. The BGA consists of hundreds of connection densely packed together in rows or patterns to save space on the circuit. for mor detil see on this link below :…
BGA Reballing Problem
How to check resistant value to check for bad chip on this link :
How to Identified missing pad before placed the chip on this link :
How to modification cooling system on chips due Over heat chip after reballing or replacing the Chip on this link :
How to Tracking joining pad by testing continuity on chip on this link :
LVDS( Low-voltage differential signaling) knowing as LCD panel is a measuring point to get know Power requarement present or missing.Missing power on this point may cause LCD/LED lossing the power and can't display .Inverter Supplay or inv_pwm enable signal missing could cause back ligh off and monitor goes dark . Missing +3VS_LCD make LCD video loos the power .BL_EN_CON is enable signal from BL_EN and some of enable signal missing couse no output from PCH .Trace any missing voltage and signal source to found the problem ,try to inject any missing voltage from psu and if they work,we just need to get same voltage from somewhere near to jumper.see on this link for more detil :…
40 pin LCD PANEL
Missing LCD VIN 19V will couse Inverter off ,no back ligh will happen
Misssing DIS_OFF will couse LCD/LED off ,this enable signal come from BK_OF and finaly signalized from Embedded controler (KB930QF).LCD POWER CIRCUIT also get enable signal from PCH and VGA to activated +LCDVDD_CONN.
To get more confident check also Group Foto Album ,there is 19 Album and every single album and foto having tutorial on it ..Check Also File on the group to get an other tutorial ,Scematic and Bios back up according each single PCB code .
Note : Make your Donation USD 49.00 to get 6 month Book Full access to Paypal ID ,book link access will be open in 24 Hours.
click Donate button on the righ side of this page or you can make a donation using Western Union for US$ 49 to Sepriadi Putra MM (Indonesia) ID NO : 3404101809690003.

Thursday, March 19, 2015

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Thursday, June 12, 2014

ACPI (Advanced Configuration and Power Interface) power management

ACPI is defined as a platform interface to the hardware detection, monitoring power management configuration. Determining the multiprocessor specification and Plug and Play devices. Besides power management aims to conserve power by stopping the power supply when not in use. Stages are controlled by the embedded operating system or known as Bios firmware file.
This firmware is executed with SPI Flash (Flash memory) electronic storage media that can be erased and reprogrammed electrically. (EEPROM electrically erasable programmable read-only memory). Firmawe this only works when run on the same circuit that has been in the program with Embedded controller and PCH were recorded.
This firmware is used to execute commands Basic input output system by sending a signal switches on the command input (trigger) S5_ON at SIO or embedded controller then forwards the order to the PCH (south bridge) switching system that activates the power supply to the Processor , Memory, Graphic Chip and others.

Power management hardware trigger events called system control interrupt (SCI), or simply setting the stage language that is tailored to the trigger signal power distribution stages.
The following outlines the stages of Power state governed by ACPI

1. S0: Trigger / gate driver signal or ordered by ACPI ready to pass power used by the device.

2. S3: Suspend State Signal. Suspension of the power distribution awaiting confirmation of Embedded controller to be enabled.

3. S5: State soft-off signal. All activities will cease, In addition to managing the transition between phases of the distribution of power, ACPI also manage the power supply of the individual devices to a fine level. For example, if two or more devices sharing the same power supply, the information can be encoded in the ACPI tables so that the power supply is only active if one or both of the devices are being used.

EC Bios requires a main power supply for 3.3V ( VCC) pin 8 on the IC , we see that in the series. Pin 7 and pin 3 is also connected to VCC,Beside power and ground others Pin connected to the EC (embedded controller) as a two-way interface to process binary data and run circuit power management.

Tuesday, June 3, 2014


Laptop Motherboard need 3V and 5V power system. This 3V_ALW supply VSB (voltage switch button)-EC Bios IC-EC (embedded controller)-SB(South bridge) and more other important component .5V suplay power Source for any switching transistor and device .(USB-HDD-Optical etc).
Without this 3V and 5V Power circuit board will totally death.
RT8206A/B dual step-down, switch-mode powersupply
(SMPS) controller generates logic-supply voltages
in battery-powered systems. The RT8206A/B includes two
pulse-width modulation (PWM) controllers fixed at 5V/
3.3V or adjustable from 2V to 5.5V. An optional external
charge pump can be monitored through SECFB(RT8206A).
This device also features a linear regulator
providing a fixed 5V output. The linear regulator provides
up to 70mA output current with automatic linear-regulator
bootstrapping to the BYP(pin 9)switchover source voltage input for the LDO. .
The RT8206A/B includes
on-board power-up sequencing, the power-good outputs,
internal soft-start, and internal soft-discharge output that
prevents negative voltages on shutdown.

Checking this IC need to know how they work and knowing important input and output Voltage .
1.VIN (Pin 6) 6v-25V
Power-supply Input.This input value between 6V to 25V according adapter or battery usage and ADP+power source. VIN is used for the constant on-time
PWM one shot circuits. VIN is also used to power the
linear regulators. The linear regulators are powered by
SMPS1 if VOUT1 is set greater than 4.66V and BYP is
tied to VOUT1.
2.ENLDO (Pin 4) 6V-15V
LDO Enable Input. The REF/LDO is enabled if ENLDO is
within logic high level and disable if ENLDO is less than
the logic low level.This power input between 6V to 15V ,some of other circuit manufacture powered VIN or B+ and the other using diode .
After VIN and ONLDO power present LDO(pin 7) will having output for 5V than supply VL(Voltage Linear) to activate EN1(pin 14) and En2(pin 27).
EN1 is SMPS1 input enable than SMPS output will trigger Upper n channel gate trough UGATE1(pin 15) for 5V .
EN2 is SMPS2 input enable for UGATE2 than SMPS output will trigger Upper n channel gate trough UGATE1(pin 15) for 5V .High-Side MOSFET Floating Gate-Driver Output for SMPS1. and swings between PHASE1/2 and BOOT1/2.
PVCC (pin 19) PVCC is the supply voltage for the low-side MOSFET
driver LGATEx. Connect a 5V power source to the PVCC
pin (bypass with 1uF MLCC capacitor to PGND if
necessary). There is an internal 10Ω connecting from
PVCC to VCC. Make sure that both VCC and PVCC are
bypassed with 1uF MLCC capacitors.PVCC input coming from VL .if LDO no voltage present than PVCC will not triger Lower n channel mosfet.VCC (pin3) is analog suplay input voltage for PWM core.with out this power SMPS will not activated .Be ware also PGND need for SMPS power ground..
If VIN present 6-25V and ONLDO present 6 to 15V but LDO not present .check feedback on pin 7 LDO.if there is no feedback positively RT8206B damage.
If VIN present 6-25V and ONLDO present 6 to 15V and LDO present for 5V positively RT 8206B on good condition .Make sure LDO continuity to VL and triger EN1 and activated SMPS1.SMPS2 will activated after SMPS1 activated and become gate driver for both upper n channel 3V and 5V.
If all power above available but Ugate1 and 2 doesn't comes out check FB1 SMPS1 Feedback Input. Connect FB1 to VCC or GND for
fixed 5V operation. Connect FB1 to a resistive voltagedivider
from VOUT1 to GND to adjust output from 2V to
5.5V.and do same way for FB 2 to adjust output from 2V to 3.3V.

Tuesday, November 19, 2013



Wednesday, October 16, 2013

Checking Laptop Motherboard Problem by the Symtom and make Service log measurement

Service log is made by technicians to make a record of faulty  motherboard electricity and signal system , every single voltage and signal measurement are notice in this log.To narrow the search of missing voltage and signal,
divide by checking  symptom of faulty to be :

1.Dead motherboard
no led indicator at all,no fan moving ,no power .This motherboard require an adapter voltage (12V_15V_16V_18.5V_19V_20V) also 3V and 5V to completely VALW power supply need.without this impossible motherboard to a life.
Starting with checking power jack to ensure adapter continuity supply P channel mosfet transistor(adp fet's) ended to P channel mosfet transistor for battery fet.This line power contribution called Main circuit line of VALW power supply.Open schematic (ensure match motherboard and schematic code)for charger IC page and trace started from DC jack to adp P channel mosfet (or same motherboard using Inductor or Diodes to replace transistor on circuit) make sure continuity supply for charger IC VCC,DC/DC main supply IC VCC and each Upper N channel SOURCE to produced 3V and 5VALW.
Signal confirmation EC Bios working name is RSMRST# for 3.3V

2.No display motherboard
led indicator on,switch on but no internal or external display.
There are 3 boot strap device supported to make motherboard load to display of course after Bios system working properly :
Without this motherboard will not be able to display.power name by VCCORE and enable signal called VR_ON or V_RON as a trigger from Embedded controler(EC) to enable or disable VCCORE IC.Processor need power supply greater than 1.05V but some AMD processor only need power greater than 0.9V.

Sodim power called VCCRAM.There are 2 VCCRAM need to make sodim working :1.5V and 0.9VTT for DDRIII and 1.8V_0,75VTT for DDRII.Get the schematic and find VCCRAM/VTT measuring point to ensure sodim powered well.

Chip Power called VCCP.There are very complex power supply system.Chip need 19VALW-5/3VALW-5/3VS-1.2VS-1.05VS.Chip also have they own RAM and need power supply to working.Finding measuring point on chip by opening chip page on schematic or by checking Voltage rail for specific motherboard.
Signal confirmation chip was ok on chip PWRGOOD for 3.3V or tolerance 10%

Note every missing power and replace damage component.

3.Power Drop
Led Indicator on ,switching on,on for few second after that back off.
This symptom happen because power spike or there is shortage on VS line.
Processor and Chip are most  which can cause power spike,look at VCORE and VCCP circuit line ,circuit has provide stockpile empty pad to add some more capacitor to anticipate power spike during boot up process.
The other problem of power drop are some shorted on VS line ,so after switch on VS active 1 or more VS line got a feed back caused power down and shutdown the system.

Adapter led Blinking or drop,Current high Voltage down,no movement at all(Dead shorted motherboard)
This feed back comes from VALW main power supply line.Checking this on schematic by opening Charger IC page and trace any sorted component on VIN and VBAT+line.Finding shorted by checking all component having Cathoda and anoda .this are most potential component conduce shorted.

5.No switch/Can not Switch on
there are few system switch found for different circuit manufacture.measurung switch voltage on one of switch button pin,before switch standby power available for 17~19V comes from 51_ON#and after switch on power switching vcc 3.3V replace 51_ON# supply than EC_ON# one of pin Embedded controller reacted for on/off mode.
Switching system shorted power switch to the ground,while shorted vcc become zero volt than 3,3V_vcc replace 51_ON# 17-19V become 3.3V.this signal read by Embedded controller to switch on or switch off the system.
The other system used 3 or 5V switch button VCC.this system using curve signal reading .when 3or5V shorted to the ground by switching button ,3V will drop to zero volt(for 1 second) EC will reacted to power on the system and when 3or5V shorted for more than 3 second ,EC will reacted to power off the system.
Make sure this system running properly beside checking for spi flash running on this EC and EC powered well.
Can not switch also will happen if NBPWR_BTN# or what ever pin called.if this signal missing event all system above checked well,the switching power on system will not work.