LG LG-840G User manual
Internal Use Only
Service Manual
LG840G
Date: September, 2012 / Issue 1.0
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LGE Internal Use Only
Table Of Contents
1. INTRODUCTION..................................................................... 3
1.1 Purpose....................................................................................................3
1.2 Regulatory Information ....................................................................3
1.3 Abbreviations........................................................................................5
2. PERFORMANCE...................................................................... 7
2.1 System......................................................................................................7
2.2 Using Conditio......................................................................................7
2.3 Accessary ................................................................................................7
2.4 Network...................................................................................................8
2.5 Current Consumption..................................................................... 13
2.6 Usage Time ( AT & T spec).............................................................. 13
2.7 RSSI......................................................................................................... 13
2.8 Battery Bar........................................................................................... 14
2.9 Heat Emissio ....................................................................................... 14
2.10 Color Temperature......................................................................... 14
2.11 LG840G Figure.................................................................................15
3. TECHNICAL BRIEF................................................................ 16
3.1 RF Technical Description................................................................16
3.2 WCDMA Part....................................................................................... 17
3.3 EDGE/GPRS/GSM RF block............................................................ 23
3.4 Control Flow ....................................................................................... 29
3.5 BB Technica Description ................................................................ 30
3.6 Power management........................................................................ 42
4. TROUBLE SHOOTING .......................................................... 45
4.1 RF Component...................................................................................45
4.2 RF Path..................................................................................................47
4.3Trouble Shooting of GSM Part (GSM850/900/1800/1900)
......................................................................................................................... 49
4.4Trouble Shooting of WCDMA Part............................................. 58
4.5 Checking Bluetooth Block ............................................................ 66
4.6 Checking WiFi Block ........................................................................ 69
4.7 Checking GPS Block......................................................................... 72
4.8 Power ONTroubleshooting..........................................................76
4.9 Charger Troubleshooting.............................................................. 79
4.10 USB Troubleshooting.................................................................... 80
4.11 USIM Detect Troubleshooting..................................................82
4.12 Camera Troubleshooting............................................................ 85
4.13 Main Keypad BacklightTroubleshooting.............................87
4.14 LCD Troubleshooting.................................................................... 88
4.15 Vibrator............................................................................................... 90
4.16 Receiver Path................................................................................... 91
4.17 Headset path ................................................................................... 93
4.18 Speaker phone path..................................................................... 95
4.19 Main microphone.......................................................................... 97
4.20 Headset microphone.................................................................... 99
5. DOWNLOAD.......................................................................101
6. BLOCK DIAGRAM...............................................................120
7. CIRCUIT DIAGRAM ............................................................130
8. BGA PIN MAP.....................................................................141
9. PCB LAYOUT.......................................................................145
10. CALIBRATION...................................................................153
10.1 Conguration ofTachyon.........................................................153
10.2 How to use Tachyon....................................................................156
11. EXPLODED VIEW & REPLACEMENT PART LIST .............158
11.1 EXPLODED VIEW...........................................................................158
11.2 Replacement Parts.......................................................................161
11.3 Accessory ........................................................................................186
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1. INTRODUCTION
1. INTRODUCTION
Copyright © 2007 LG Electronics. Inc. All right reserved.
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1.1 Purpose
This manual provides the information necessary to repair, calibration, description and download the
features of this model.
1.2 Regulatory Information
A. Security
Toll fraud, the unauthorized use of telecommunications system by an unauthorized part (for example,
persons other than your company’s employees, agents, subcontractors, or person working on your
company’s behalf) can result in substantial additional charges for your telecommunications services.
System users are responsible for the security of own system. There are may be risks of toll fraud associated
with your telecommunications system. System users are responsible for programming and configuring the
equipment to prevent unauthorized use. The manufacturer does not warrant that this product is immune
from the above case but will prevent unauthorized use of common-carrier telecommunication service of
facilities accessed through or connected to it.
The manufacturer will not be responsible for any charges that result from such unauthorized use.
B. Incidence of Harm
If a telephone company determines that the equipment provided to customer is faulty and possibly
causing harm or interruption in service to the telephone network, it should disconnect telephone service
until repair can be done. A telephone company may temporarily disconnect service as long as repair is not
done.
C. Changes in Service
A local telephone company may make changes in its communications facilities or procedure. If these
changes could reasonably be expected to affect the use of the this phone or compatibility with the
network, the telephone company is required to give advanced written notice to the user, allowing the user
to take appropriate steps to maintain telephone service.
D. Maintenance Limitations
Maintenance limitations on this model must be performed only by the manufacturer or its authorized
agent. The user may not make any changes and/or repairs expect as specifically noted in this manual.
Therefore, note that unauthorized alternations or repair may affect the regulatory status of the system and
may void any remaining warranty.
1. INTRODUCTION
1. INTRODUCTION
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1. INTRODUCTION
Copyright © 2007 LG Electronics. Inc. All right reserved.
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E. Notice of Radiated Emissions
This model complies with rules regarding radiation and radio frequency emission as defined by local
regulatory agencies. In accordance with these agencies, you may be required to provide information such
as the following to the end user.
F. Pictures
The pictures in this manual are for illustrative purposes only; your actual hardware may look slightly
different.
G. Interference and Attenuation
Phone may interfere with sensitive laboratory equipment, medical equipment, etc.Interference from
unsuppressed engines or electric motors may cause problems.
H. Electrostatic Sensitive Devices
ATTENTION
Boards, which contain Electrostatic Sensitive Device (ESD), are indicated
by the sign. Following information is ESD handling:
• Service personnel should ground themselves by using a wrist strap when exchange system boards.
• When repairs are made to a system board, they should spread the floor with anti-static mat
which is also grounded.
• Use a suitable, grounded soldering iron.
• Keep sensitive parts in these protective packages until these are used.
• When returning system boards or parts like EEPROM to the factory, use the protective
package as described.
2. INTRODUCTION
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1. INTRODUCTION
Copyright © 2007 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only 6/140
1.3 Abbreviations
For the purposes of this manual, following abbreviations apply:
Offset Phase Locked LoopOPLL
Light Emitting DiodeLED
Low Drop OutputLDO
Liquid Crystal DisplayLCD
Intermediate FrequencyIF
International Portable User IdentityIPUI
Global System for Mobile CommunicationsGSM
General Purpose Interface BusGPIB
Gaussian Minimum Shift KeyingGMSK
Flexible Printed Circuit BoardFPCB
Electrostatic DischargeESD
Electrical Erasable Programmable Read-Only MemoryEEPROM
Digital Signal ProcessingDSP
dB relative to 1 milli wattdBm
Digital Communication SystemDCS
Digital to Analog ConverterDAC
Constant Current – Constant VoltageCC-CV
Bit Error RatioBER
BasebandBB
Automatic Power ControlAPC
1. INTRODUCTION
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1. INTRODUCTION
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Wireless Application Protocol
WAP
Voltage Control Temperature Compensated Crystal OscillatorVCTCXO
Voltage Controlled OscillatorVCO
Universal Asynchronous Receiver/TransmitterUART
Time Division Multiple AccessTDMA
Time Division DuplexTDD
Travel AdapterTA
Side Tone Masking RatingSTMR
Pseudo SRAMPSRAM
Static Random Access MemorySRAM
Sending Loudness RatingSLR
Subscriber Identity ModuleSIM
Surface Acoustic WaveSAW
Real Time ClockRTC
Root Mean SquareRMS
Receiving Loudness RatingRLR
Radio FrequencyRF
Public Switched Telephone NetworkPSTN
Phase Locked LoopPLL
Programmable Gain AmplifierPGA
Printed Circuit BoardPCB
Power Amplifier ModulePAM
1. INTRODUCTION
2. PERFORMANCE
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2. PERFORMANCE
2.1 System
2.
2 Using Condition
Item Type / Spec.
1.Type DOP
2.Size 103.6 x 59.8 x 11.7mm
3.Weight 110.9±5.5g (1000mAh Battery)
4.Battery 1000 mAh (Li-Ion)
5.LCD Type TFT QVGA LCD(3.2”)
6.Accessory
1) Travel Adaptor
2) USB Cable
3) Ear-Mic Set
4) Micro SD
1) Input : AC 100~240V , Output : 5.1V, 700mA
2) Micro-USB type(Not in Box)
3) 3.5phi Ear Phone(Not in Box)
4) 2GBYTE
Item Spec. Min. Typ. Max. Unit
Output
Voltage
DC Power 5.1 Vdc
Battery Power 3.2 3.7 4.2 Vdc
Input Voltage 100 110 240 Vac
Using
Temperature 0 47 ℃
2.3 Accessary
Input : AC 100~240VOutput: 5.1V, 700mATravel Adapter
Charging Voltage : 4.2V
Standart Charging Current: 500mA
Li-Ion Polymer, 1000mAhBattery
RemarkType/Spec.Item
SD Card 2GBYTE MICRO SD CARD 15.0x11.0x1.0MM
TR 8P 2GB MicroSD Card
2.1 System
2.2 Using Condition
2.3 Accessary
2. PERFORMANCE
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2.4 Network
1) GSM Tx/Rx Frequecy characteristics
Item Specification
Phase Error Rms : 5°
Peak : 20 °
Frequency Error GSM : 0.1 ppm
DCS/PCS : 0.1 ppm
EMC(Radiated Spurious Emission
Disturbance) GSM/DCS : < -28dBm
Transmitter Output power and Burst
Timing
GSM : 5dBm – 33dBm ±3dB
DCS/PCS : 0dBm – 30dBm ±3dB
Burst Timing <3.69us
Spectrum due to modulation out to less
than 1800kHz offset
200kHz : -36dBm
600kHz : -51dBm/-56dBm
Spectrum due to modulation out to
larger than 1800kHz offset to the edge of
the transmit band
GSM :
1800-3000kHz :< -63dBc(-46dBm)
3000kHz-6000kHz : <-65dBc(-46dBm)
6000kHz < : < -71dBc(-46dBm)
DCS :
1800-3000kHz :< -65dBc(-51dBm)
6000kHz < : < -73dBc(-51dBm)
Spectrum due to switching transient 400kHz : -19dBm/-22dBm(5/0), -23dBm
600kHz : -21dBm/-24dBm(5/0), -26dBm
Reference Sensitivity – TCH/FS Class II(RBER) : -105dBm(2.439%)
Usable receiver input level range 0.012(-15 - -40dBm)
Intermodulation rejection – Speech
channels
±800kHz, ±1600kHz
: -98dBm/-96dBm (2.439%)
AM Suppression
-GSM : -31dBm - DCS : -29dBm -98dBm/-96dBm (2.439%)
Timing Advance ±0.5T
2.4 Network
1) GSM Tx/Rx Frequecy characteristics
2. PERFORMANCE
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2) WCDMA Tx/Rx Frequecy characteristics
Item Specification
Transmit Frequency WCDMA850 : 824 MHz ~ 849 MHz
WCDMA1900 : 1850 ~ 1910 MHz
Maximum Output Power +24 dBm / 3.84 MHz, +1 / -3 dB
Frequency Error within ±0.1 PPM
Open Loop Power Control Normal Conditions : within ±9 dB,
Extreme Conditions : within ±12 dB
Minimum Transmit Power < -50 dBm /3.84 MHz
Occupied Bandwidth < 5 MHz at 3.84 Mcps (99% of power)
Adjacent Channel Leakage
Power Ratio (ACLR)
> 33 dB @ ±5 MHz,
> 43 dB @ ±10 MHz
Spurious Emissions
|f-fc| > 12.5 MHz
< -36 dBm / 1 kHz RW @ 9 kHz ≤ f < 150 kHz
< -36 dBm / 10 kHz RW @ 150 KHz ≤ f < 30 MHz
< -36 dBm / 100 kHz RW @ 30 MHz ≤ f < 1 GHz
< -30 dBm / 1 MHz RW @ 1 GHz ≤ f < 12.75 GHz
< -41 dBm / 300 kHz RW @ 1893.5 MHz < f < 1919.6 MHz
< -67 dBm / 100 kHz RW @ 925 MHz ≤ f ≤ 935 MHz
< -79 dBm / 100 kHz RW @ 935 MHz < f ≤ 960 GHz
< -71 dBm / 100 kHz RW @ 1805 MHz ≤ f ≤ 1880 MHz
Transmit Inter-modulation < -31 dBc @ 5 MHz & < -41 dBc @ 10 MHz
when Interference CW Signal Level = -40 dBc
Error Vector Magnitude < 17.5 %, when Pout ≥ -20 dBm
Peak Code Domain Error < -15 dB at Pout ≥-20 dBm
2) WCDMA Tx/Rx Frequecy characteristics
2. PERFORMANCE
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3) WCDMA Rx Frequecy characteristics
Item Specification
Receive Frequency WCDMA850 : 849 MHz ~ 894 MHz
WCDMA1900 : 1930MHz ~ 1990 MHz
Reference Sensitivity Level BER < 0.001 when Îor = -106.7 dBm / 3.84 MHz
Maximum Input Level BER < 0.001 when Îor = -25 dBm / 3.84 MHz
Adjacent Channel Selectivity
(ACS)
ACS > 33 dB where BER < 0.001 when Îor = -92.7 dBm / 3.84 MHz
& Ioac = –52 dBm / 3.84 MHz @ ±5 MHz
Blocking Characteristic
BER < 0.001 when Îor = -103.7 dBm / 3.84 MHz
& Iblocking = -56 dBm / 3.84 MHz @ Fuw(offset) = ±10 MHz
or Iblocking = -44 dBm / 3.84 MHz @ Fuw(offset) = ±15 MHz
Spurious Response BER < 0.001 when Îor = -103.7 dBm / 3.84 MHz & Iblocking = -44 dBm
Intermodulation
BER < 0.001 when Îor= -103.7 dBm / 3.84 MHz
& Iouw1 = -46 dBm @ Fuw1(offset) = ±10 MHz
& Iouw2 = -46 dBm / 3.84 MHz @ Fuw2(offset) = ±20 MHz
Spurious Emissions < -57 dBm / 100 kHz BW @ 9 kHz ≤ f < 1 GHz
< -47 dBm / 1 MHz BW @ 1 GHz ≤ f ≤ 12.75 GHz
3) WCDMA Rx Frequecy characteristics
2. PERFORMANCE
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4) HSDPA Tx/Rx Frequecy characteristics
Item Specification
Transmit Frequency 824 MHz ~ 849 MHz
1850MHz ~ 1910 MHz
Maximum Output Power Sub-Test
1=1/15, 2=12/15 21~25dBm / 3.84 MHz
3=13/15 4=15/8 20~25dBm / 3.84 MHz
5=15/7 6=15/0 19~25dBm / 3.84 MHz
HS-DPCCH
Spectrum Emission Mask
Sub-Test : 1=1/15, 2=12/15, 3=13/15, 4=15/8, 5=15/7, 6=15/0
Adjacent Channel
Leakage
Power Ratio (ACLR)
Sub-Test : 1=1/15, 2=12/15, 3=13/15, 4=15/8, 5=15/7, 6=15/0
> 33 dB @ ±5 MHz
> 43 dB @ ±10 MHz
Error Vector Magnitude 3GPP Not Complete
Sub-
test in
table
C.10.1.4
Power
step Power step slot boundary
Power
step size,
P [dB]
Transmitter
power step
tolerance
[dB]
5
1 Start of Ack/Nack 6 +/- 2.3
2 Start of CQI 1 +/- 0.6
3 Middle of CQI 0 +/- 0.6
4 End of CQI 5 +/- 2.3
Frequency offset from
carrier △f Minimum requirement Measurement
Bandwidth
2.5 ~ 3.5 MHz -35-15×(△f-2.5)dBc 30 kHz
3.5 ~ 7.5 MHz -35-1×(△f-3.5)dBc 1 MHz
7.5 ~ 8.5 MHz -35-10×(△f-7.5)dBc 1 MHz
8.5 ~ 12.5 MHz -49dBc 1 MHz
4) HSDPA Tx/Rx Frequecy characteristics
2. PERFORMANCE
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5) HSDPA Rx Frequecy characteristics
Item Specification
Receive Frequency
849 MHz ~ 894 MHz
1930 MHz ~1990 MHz
Maximum Input Level
(BLER or R), 16QAM Only
Sub-Test : 1=1/15, 2=12/15, 3=13/15, 4=15/8, 5=15/7, 6=15/0
BLER < 10% or R >= 700kbps
5) HSDPA Rx Frequecy characteristics
2. PERFORMANCE
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2.5 Current Consumption
2.6 Usage Time ( AT & T spec )
2.7 RSSI
WCDMA Only
GSM Only
Standby
3.0mA(DRX=1.28sec) ↓3.00mA(PP=5) ↓
Talk Mode
270 mA (Tx Lvl : 12dBm) ↓
280 mA (Tx Lvl:5) ↓
Power Off
(During Backup Battery Charging)
300㎂↓
500㎂↓
300㎂↓
500㎂↓
Stand by Voice Call VT
WCDMA
Only
275 hours↑= 3.80mA ↓
(1000mAh battery,
DRX cycle = 1.28)
200 mins ↑= 300mA ↓
(1000mAh battery, TX = 13dBm, low
power mode )
/
GSM
Only
275 hours ↑= 3.80mA ↓
(1000mAh battery,
Paging frame class6)
200 mins ↑= 300mA ↓
(1000mAh battery, TX = Level 5)
Cell Power [dBm] GSM850/900 DCS/PCS WCDMA
BAR 5 -> BAR 4 -79 ±2dBm -79 ±2dBm -75 ±2dBm
BAR 4 -> BAR 3 -88 ±2dBm -88 ±2dBm -85 ±2dBm
BAR 3 -> BAR 2 -97 ±2dBm -97 ±2dBm -95 ±2dBm
BAR 2 -> BAR 1 -103 ±2dBm -103 ±2dBm -101 ±2dBm
BAR 1 -> No service ~ No service ~ No service ~ No service
2.5 Current Consumption
2.6 Usage Time ( AT & T spec )
2.7 RSSI
2. PERFORMANCE
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2.8 Battery Bar
2.9 Heat Emission
2.10 Color Temperature
Indication Standby
Bar3 3.74 ±0.05V
Bar 3 →2 3.74 ±0.05V
Bar 2 →1 3.65 ±0.05V
Bar 1 →Blink 3.588 ±0.05V
Power Off 3.35 ±0.05V
Heat Emission 55 oC (AT&T Heat Emission Standard, Metal Material
below 55degrees)
Color Temperature 6000 ~ 9000
2.8 Battery Bar
2.9 Heat Emission
2.10 Color Temperature
2. PERFORMANCE
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2.11 LG840G Figure
2.11 LG840G Figure
3. TECHNICAL BRIEF
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GSM1800/1900 RX1
GSM1800/1900 RX2
GSM900RX1
GSM900RX2
GSM900_RX_M
GSM900_RX_P
DCS/PCS_RX_P
DCS/PCS_RX_M
RX_IN_G_LBM
RX_IN_G_LBP
RX_IN_G_HBP
RX_IN_G_HBM
FEM
LMSP33QJ
2G PAM
RF3194
TX_HB
TX_LB
GSM1800/1900TX
GSM850/900TX
HB_RFOUT
LB_RFOUT
GSM_HB_TX
GSM_LB_TX
TX_OUT_G_HB
TX_OUT_G_LB
HB_RFIN
LB_RFIN
Duplexer W850 / GSM850_RX_P
W850 / GSM850_RX_M
RX1
RX2 RX_IN_U_G_LBM
RX_IN_U_G_LBP
TX RFOUT_LB
Duplexer TX RFOUT_HB
3G PAM
SKY77196
W1900_RX_P
W1900_RX_M
RX1
RX2 RX_IN_U_G_BH1M
RX_IN_U_G_BH1P
BPF
BPF
B9425
B9459
RFIN_LB
RFIN_HB
TX_OUT_U_LB
TX_OUT_U_HB1
QSC6270
WCMDA_850
WCMDA_1900
ANT
ANT
TRX1TRX2 VRAMP GSM_PA_RAMP PA_DAC
CPL_OUT PWR_DET_IN
PWR_DET
LG840G only supports RF Band GSM850/900/1800/1900
WCDMA 850/1900
Main ANTENNA
Main CLK
19.2MHz
Sleep CLK
32.768KHz
■T3H RF Block Diagram
3. TECHNICAL BRIEF
3.1 RF Technical Description
The RF platform of LG840G supports two dierent communication modes (WCDMA/GSM modes) including six communi-
cation bands (W1900/W850/GSM850/GSM900/GSM1800/GSM1900).
The all the RF blocks can be divided into three main parts, which are a WCDMA part, a GSM, and a Antenna switch
module. The simplied block diagram is shown in Figure 3.1.1
3. TECHNICAL BRIEF
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17
p
a
g
e Fi
g
ure 3.2.1
p g g
Figure 3.2.1. WCDMA RF structure
3.2 WCDMA Part
The W-CDMA transceiver uses dierential analog in-phase and quadrature-phase interfaces, that is an IQ interface, both
in the receiver and information path.
The transceiver has the following getransmitter neral features:
- Power class : Power class 3 (+24dBm) in Band II and V
- Zero-IF Receiver.No IF lter needed
- Direct IQ modulation transmitter
3. TECHNICAL BRIEF
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18
p
a
g
e Fi
g
ure 3.2.1.1
p g g
Figure 3.2.1.1 WCDMA Transceiver Architecture
3.2.1 Transmitter Part
WCDMA Transmitter Block
The QSC62x0 device supports tri-band UMTS transmissions with three separate driver amplier outputs; in fact, most Tx
active circuits are contained within the device. All three UMTS transmit paths (Figure 3.2.1.1) begin with a single, shared
analog baseband signal from the device’s baseband circuits. The baseband signal is composed of two dierential lines,
one in-phase component and one quadrature-phase component. Each component is low pass ltered and amplied to
levels sucient for driving the quadrature upconverters. There are two upconverters — one for low-band signals and one
for high band — but only one upconverter is active at a time.
3. TECHNICAL BRIEF
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The active upconverter’s output is at the desired RF channel frequency and drives the QSC output stages.
These RF circuits include multiple variable-gain stages that provide transmit AGC control.
A greater than 81 dB gain control range is realized using information from the on-chip Tx power detector combined with
a control signal from the baseband circuits. The wide range of driver amplier output levels is achieved while supporting
the WCDMA standard’s requirements for ACLR, spurious emissions, Rx-band noise, etc.
The high-band driver amplier output is followed by a SPDT switch that provides two high-band outputs,
thereby fullling the tri-band UMTS requirement. The low-band output port is driven directly by its output amplier.
All three output ports are single-ended with 50ohm nominal impedance. Each requires a matching network to interface
with its band-pass lter.
Each of the three UMTS Tx output chains are functionally identical: the QSC Tx output drives the PA through the band-
pass lter and a matching network; a directional coupler provides a sample of the PA output signal; the through path of
the coupler is routed to the Tx port of the duplexer; the duplexer antenna port is connected to the antenna switch; and
the switch is connected to the antenna.
The coupler outputs provide a low-level sample of the active transmitter’s Tx power. An on-chip power-detector circuit
provides a Tx power estimate that assists in setting the transmit gains and helps ensure that the maximum allowed
output power is not exceeded. The three UMTS couplers (one for each band) use a daisy-chain conguration that allows
them to share the single, on-chip power detector circuit.
3. TECHNICAL BRIEF
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20
p
a
g
e Fi
g
ure 3.2.2.1
p g g
Figure 3.2.2.1 WCDMA Receiver schematic
3.2.2 Receiver Part
WCDMA Receiver
The antenna collects the base station forward-link signal and radiates the phone’s reverse-link signal. In the example of a
multiband, multimode phone (Figure 3.2.2.1), a switch routes the antenna signals to one of the three UMTS Rx/Tx paths,
each beginning with its own band-specic duplexer that separates that band’s receive and transmit paths
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