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Signal Name for Motherboard Manufacturers:​

List of some common signal names of Wistron Board Manufacturer:

Signal Name Description
CK-PWRGD After the South Bridge receiving VRMPWRGD, sent this signal as
high level for opening the clock.
G792-RST# The high level s4end by the temperature control chip when the
temperature is normal.
CLK_EN# After CPU power supply being normal, send the low level that
can be used to open the clock.
LID_CLOSE# Close cover switch.
KBC-PWR-BTN# Press the on/off switch to produce the trigger signal to EC.
AD_IN# , AC_IN# The power adapter detection signal to EC, the low level
represents that the adapter is inserted.
+5VALM, +3VALM The standby power supply of South Bridge.
PWR-S5-EN A control signal used to open standby voltage of South Bridge.
ACAV-IN Power adapter detection output for charging chip.
ACIN Power adapter detection input for charging chip.
DCIN Power supply input for charging chip.
+3VL 3.3V linear power supply, supply voltage to EC.
DCBATOUT Common point.
AD+ The first voltage that the power adapter converts.

List of some common signal names of Inventec:

Signal Name Description
+VADP Power adapter voltage.
ADP_EN# Power adapter enable signal; Active low level.
ADP_PRES Adapter detection output voltage.
+VBATR Common point voltage.
+3VAL, +5VAL Linear power supply.
PWR_SWIN_3# The signal sent by trigger switch to EC chip.
KBC_PW_ON The power signal; It is sent by EC after EC receiving trigger switch;
It is use to open the system standby power supply under the
battery mode (backup battery).
OCP Over-current protection.
LIMIT_SIGNAL The power adapter connector intermediate pin; Power
identification signal.
+V3A, +V5A Power supply of standby system.
VCCI_POR#3 The initial reset signal of EC.

List of some common signal names of Compal Manufacturer:

Signal Name Description
SUS_STAT# Sent by the South Bridge; The low level indicates that the
system will be in power-down (save power) mode.
BCLK The front side bus clock signal.
ICH_POK PWROS for the South Bridge; Inform the South Bridge system
voltage power good.
VGATE CPU core voltage power-good signal.
+CPU_CORE CPU core voltage.
+VCCP The working voltage of CPU front side bus; This voltage
distributes in CPU, the North Bridge, and the South Bridge.
SUSP# S0 voltage open signal.
SYSON S3 voltage open signal.
PBTNOUT# The boot trigger signal sent by EC to the South Bridge.
ON/OFF# The trigger signal sent by boot trigger circuit to EC.
ON/OFFBTN# Press power on key signal.
+3VALW, +5VALW Inserting the adapter, that is the opened voltage.
VL 5V linear power supply.
PACIN The detection output signal is inserted to the adapter.
B+ Common point voltage.

List of some common signal names of Apple:

Signal Name Description
ONEWIRE_EN ONEWIRE enable signal; For the adapter to identify circuit
(the power connector LED green light).
ACPRN Low level ACPRN signal sent by charging chip after the
adapter is detected.
SMC_BATT_CHG_EN The charging enable signal sent by SMC; Active-high level.
SMC_ADAPTER_EN The high-level signal output by SMC after receiving the
adapter detection signal.
SMC_BC_ACOK The Adapter detection signal; Active – high level.
VR_PWRGD_CK505_L The lower level signal of open clock; After CPU power
supply chip generating CPU voltage normally, it will send
the low level signal to open clock.
VR_PWRGOOD_DELAY The power good signal sent by CPU power supply after
generating CPU voltage normally and it will delay to send
the power-good.
ALL_SYS_PWRGD Convergence from all power supply good signal except CPU
power supply
1V8S3_RUNSS S3 state voltage (memory supply) of 1.8V open signal.
PM_BATLOW_L The indicator signal of low battery voltage; Active-low
=PPBUSA_G3H Common point voltage.
PP3V3_G3_SB_RTC 3.3V power supply of the South Bridge RTC circuit.
=PP3V3_S5_REG 3.3V power supply in the condition of S5 provided the
standby voltage to the South Bridge and others.
=PP3V42_G3H_REG 3.42V power supply in the condition of G3 equivalent to
the linear power supply of other machine.

List of some common signal names of Quanta:

Signal Name Description
NBSWON# Trigger signal for power on; Press the power on key to produce
high-lowhigh signal to EC.
D/C# Inverse relationship with ACIN (Just for motherboard with
D/C# signal, where the motherboard is without BL/C# signal).
BL/C# Represents high level, low battery (only for battery mode).
CPURST# CPU reset signal; The North Bridge sent CPURST# to CPU after
received PLTRST#.
PCIRST# The PCI reset; Used for resetting the device on the PCI bus
when powered on.
PLTRST# The platform reset signal; After the South Bridge sending
CPUPWRGD signal, through the delay buffer sent PLTRST#
CPUPWRGD In the South Bridge internal, PWROK pin and VRMPWRGD pin
signal through the logic generated CPUPWRGD.
CK_PWRGD The South Bridge sent CL-PWRGD open clock chip after
receiving VRMPWRGD.
VR-PWRGD-CK410# CPU core voltage power managed the clock open signal from
chip; Active low level.
DELAY_VR_PWG CPU core voltage power-good signal.
PWROK_EC After EC received high level HWPG signal, delay producing the
PWROK_EC signal.
HWPG By the PG Logic and all power supply except the CPU core
power supply.
VR_ON The CPU core voltage opening signal sent by EC.
MAINON After EC receiving SLP_S3# from the South Bridge, after that
producing S3 voltage opening signal.
SUSON After EC receiving SLP_S5# from the South Bridge, then
producing S3 voltage opening signal.
S5_ON The opening signal of the South Bridge standby voltage sent by
EC; Its use to convert the PCU to voltage S5.
SLP_S3#, SLP_S4# ACPI controller signal sent by the South Bridge is used to
opening voltage when the power is turned on, and it also used
to shutting off voltage when the power is turned off.
DNBSWON# EC sent high-low-high effective trigger signal to the South
Bridge PWRBTN#.
+3VSUS, +5VSUS The voltage under the condition of S3; Memory power supply;
Sent by EC and opened by SUSON.
3V_S5 The voltage under the condition of S5.

+3VPCU, +5VPCU EC Standby power supply
3V_AL, 5V_AL, VL 3V, 5V Linear power supply
ACIN, ACOK Power Adapter detection
VIN The common point voltage

List of some common signal names of ASUS:

Signal Name
OTP_RESET# CPU over temper
HW_PROTECT# CPU over temper
FORCE_OFF# The forced shutd
voltage protectio
KBCRSM The keyboard wa
LID_KBC# The close-lid slee
LID_SW# Close-lid sleep sw
this signal is low
GATE_PWR_SW# The booth trigge
H_CPURST# The North Bridge
PLTRST# signal.
PM_PWROK After receiving A
CLK_PWRGD The South Bridge
receiving VRMPW
South Bridge tha
CPU_VRON EC delayed 99ms
For opening CPU
ALL_SYSTEM_PWRGD Generated by me
bus power supply
signal logic.
SUSB_ON, SUSB#_PWR S0 voltage open s
SUSC_ON, SUSC_PWR S3 voltage open s
PM_PWRBTN# After receiving PW
effective trigger t
PWRSW_EC# Laptop boot-up t
PM_RSMRST# The reset signal o
understood that
normal when rec
SUS_PWRGD SUS voltage pow

VSUS_ON SUS voltage open signal.
+3VSUS +3VO renamed to +3VSUS after jumper.
+5VSUS +5VO renamed to +5VSUS after jumper.
+3VO 3V standby voltage in S5dormant state.
+5VO 5V standby voltage in S5dormant state.
+3VA_EC +3VA renamed to +3VA_EC after through the inductance;
As the EC standby power supply.
+3VA +3VAO renamed to +3VA after jumper JP8101.
+5VA +5VAO renamed to +5VA after jumper.
+3VAO 3V linear voltage.
+5VAO 5V linear voltage.
ACIN Power adapter detection.
AC_BAT_SYS The common point voltage.

List of some common signal names of Dell:

Signal Name Signal Name
IMVP_PWRGD Power supply good signal sent by CPU power supply chip.
IMVP_VR_ON Open CPU power supply.
PBAT_PRES# Detection of insert main battery.
SBAT_PRES# Detection of insert the auxiliary battery.
+PBATT Main battery power supply terminal.
+SBATT Auxiliary/Sub battery power supply terminal.
+VCHGR Charging output voltage.
H_RESET# The North Bridge sent CPU reset signal.
H_PWRGOOD PGD reset signal sent by the South Bridge to CPU.
CLK_ENABLE# The open signal of clock chip: Activelow level.
PGD_IN One of the conditions of that CPU power supply chip sent
CLK_EN#, PGOOD and others.
+VCCP_1P05VP The front side bus power supply: 1.05V.
SUSPWROK The reset signal of all SUS power brings together to generate the
SUSPWROK signal.
RUNPWROK The PGD signal of all RUN power convergence to this signal.
+0.9V_DDR_VTTP Memory VTT power supply.
_VCC_GFX_CORE The discrete graphic card core power supply.
GFX_ON Open discrete graphics card power supply.
RUN_ON EC sent open S0 state voltage.
SUS_ON After receiving the trigger signal, EC sent SUS_ON to use to open
the South Bridge standby power supply and memory main
power supply.
POWER_SW# A low voltage signal generated by the power switch or keyboard
and EC chip receives this boot signal.
ACAV_IN The Power Adapter detection signal.
THERM_STP# Overheat protection signal; Active-low level.
ALWON EC sent a ALWON signal to the system power supply chip to
open/start-up the system power supply.
+PWR_SRC The common point voltage.
+DC_IN Power Adapter voltage input.
RTC_CELL The motherboard button battery voltage.

Operating Sequence:

Although there are countless motherboard manufacturers, there is a sequence of operation for all of them, which allows us to follow a more direct path to the defect.

Generically speaking, the operating sequence, known as the start sequence, is the definition of the state in which the card is completely off until the moment we turn on and video appears on the screen.

From the moment we connect the charger to the motherboard, several voltages appear, one after the other, which start the sequence of operation (we will address these voltages later).

Following a numerical logic, let's assume that a card connects and displays video with 10 voltages (T1, T2, T3, T4, T5, T6, T7, T8, T9, T10), if for some reason T6 for example, does not appear (any shorted component can cause this), of course the operating sequence will be interrupted and there will also be no voltage after it (T7, T8, T9 and T10).

That is to say in this case that if T5 is present on the board, you do not need to check the voltages prior to it (T1, T2, T3 and T4), as the board only appears if the voltage before it is present.

Did you understand until now? So let's continue.

I advise that when you receive a defective laptop, the first thing you do is to understand where that defect is through the symptom. If it is on the motherboard, download the schematic diagram and look for the page of the operating sequence, as the example of the image below (schematic of the motherboard compal LA-4101P, page 5.


The sequence of operation is given from top to bottom as shown by the numerical sequence in the column on the left.
On this page of the schematic diagram you will find the main pulses and voltages for the motherboard to connect (it is important to know that both may have different names depending on the manufacturer's design)

Note: Pulse is the name given to the exchange of information between certain components of the motherboard (ex: ON/OFF# is the pulse of the power button that will turn the laptop on and off).
At first glance all these letters and numbers may seem complex, but in reality everything is very easy to understand and for that we will get straight to the point.

In the next lines we will delve into some pulses and voltages of the laptop schematic diagram:

1. Vin, B+: High voltage (originated from the charger).

2. + 3VL: Also known as VREG3. Voltage that rises in the Primary PWM (this is not yet the primary voltage of 3V).

3. +5VALW/+3VALW: The famous primary voltages. They are generated by the Primary PWM and can be measured in their respective inductors, according to the schematic diagram..

4. RSMRST#: Resume and Reset signal, responsible for resetting and making the North or South Bridge ready to work. It must be at a high level (Ex 3V) in stand by and reset to zero when pressing the power button.

5. ON/OFF#: Power button signal, it must be at a high level (usually 3V) in standby, when pressing the button it goes to 0V, making the laptop turn on. Knowing this, you will be able to diagnose a problem in the power button in seconds.

There are many other pulses and voltages that, depending on the design, may vary in name and function. But don't worry, as you study schematics diagram, you will be able to assimilate each one of them and the interpretation will become more and more simple.

As you can see, some voltages appear on the motherboard even before the power button is pressed, that is, they appear on STAND BY (only connected to a charger or battery).

This tension is known as primary. It is from these voltages that all other circuits can be fed. We will understand how they arise and how to diagnose defects in them, from now on.
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