LG CX8700, CX8700B, CX8700BWA Service Manual

Features of CX8700

1. Wave Type

CELLULAR : G7W

•

• PCS : G7W

2. Frequency Scope

Transmit Frequency (MHz)

Receive Frequency (MHz)

CELLULAR

824.82 ~ 848.19 1850~1910 869.82~893.19 1930~1990 1575.42

3. Rated Output Power :

PCS = 0.20W

4. Output Conversion Method :

5. Voltage and Current Value of Termination Part Amplifier (Catalogue included)

MODE Part Name Voltage Current Power

CELLULAR AWT6310R 4.2V 600mA 0.20W

PCS AWT6310R 4.2V 600mA 0.20W

PCS

CELLULAR = 0.20W

This is possible by correcting the key board channel.

CELLULAR

PCS

6. Functions of Major Semi-Conductors

Classification Function

MSM6550 Terminal operation control and digital signal processing

GPS

Memory MCP

(HYI0UGG0MF1P-6SS0E)

RFR6500 Converts Rx RF signal to baseband signal RFT6150 Converts baseband signal to Tx RF signal

7. Frequency Stability

• CELLULAR : ±0.5PPM PCS : ±0.1PPM

•

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Flash Memory (1Mbit) + SDRAM (512Mbit) Storing of terminal operation program

CX8700

CDMA Mobile Subscriber Unit

CX8700

SERVICE MANUAL

TRI BAND CDMA

[PCS/Cellular/GPS]

CDMA MOBILE PHONE

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CX8700

Table of Contents

General Introduction

........................................................................................................................................ 4

CHAPTER 1. System Introduction

1. System Introduction......................................................................................................................5

2. Features and Advantages of CDMA Mobile Phone .................................................................6

3. Specification...................................................................................................................................9

4. Installation ..................................................................................................................... 14

CHPATER 2. NAM Input Method

1. NAM Program Method and Telephone Number Inputting Method .................................16

CHAPTER 3. Circuit Description

1. RF Transmit/Receive Part..........................................................................................................26

2. Digital/Voice Processing Part.....................................................................................................33

CHAPTER 4. Trouble Shooting……………………………………………….…………………….37

CHAPTER 5. Safety……………………………………………………………….……………..…..88

CHAPTER 6. Glossary………………………………………………………….………………..…..91

APPENDIX……………………………………………………………………………………….….103

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CX8700

General Introduction

The CX8700 phone has been designed to operate on the latest digital mobile communication technology, Code Division Multiple Access (CDMA). This CDMA digital technology has greatly enhanced voice clarity and can provide a variety of advanced features. Currently, CDMA mobile communication technology has been commercially used in Cellular and Personal Communication Service (PCS). The difference between them is the operating frequency spectrum. Cellular uses 800MHz and PCS uses 1.9GHz. The CX8700 support GPS Mode, we usually call it tri-band phone. Also, CX8700 works on Advanced Mobile Phone Service (S-GPS). We call it dual-mode phone. If one of the Cellular, PCS base stations is located nearby, Call fail rate of triple-mode phone is less than dual-mode phone or single-mode phone. The CDMA technology adopts DSSS (Direct Sequence Spread Spectrum). This feature of DSSS enables the phone to keep communication from being crossed and to use one frequency channel by multiple users in the same specific area, resulting that it increases the capacity 10 times more compared with that in the analog mode currently used. Soft/Softer Handoff, Hard Handoff, and Dynamic RF power Control technologies are combined into this phone to reduce the call being interrupted in a middle of talking over the phone. Cellular and PCS CDMA network consists of MSO (Mobile Switching Office), BSC (Base Station Controller), BTS (Base station Transmission System), and MS (Mobile Station). The following table lists some major CDMA Standards.

CDMA Standard Designator Description

Basic air interface TIA/EIA/IS-95-A/B/C

ANSI J-STD-008

Network TIA/EIA/IS-634

TIA/EIA/IS/651

TIA/EIA/IS-41-C

TIA/EIA/IS-124

Service TIA/EIA/IS-96-B

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TIA/EIA/IS-99 TIA/EIA/IS-637 TIA/EIA/IS-657

Protocol between MS and BTS for Cellular & AMPS

Protocol between MS and BTS for PCS

MAS-BS

PCSC-RS

Intersystem operations

Nom-signaling data comm.

Speech CODEC

Assign data and fax

Short message service

Packet data

Performance TIA/EIA/IS-97

TIA/EIA/IS-98

ANSI J-STD-018 ANSI J-STD-019

TIA/EIA/IS-125

* TSB –74: Protocol between an IS-95A system and ANSI J-STD-008

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Cellular base station

Cellular mobile station

PCS personal station

PCS base station

Speech CODEC

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CX8700

Chapter1. System Introduction

1.1 CDMA Abstract

The CDMA mobile communication system has a channel hand-off function that is used for collecting the information on the locations and movements of mobile telephones from the cell site by automatically controlling several cell site through the setup of data transmission routes, and then enabling one switching system to carry out the automatic remote adjustment. This is to maintain continuously the call state through the automatic location confirmation and automatic radio channel conversion when the busy subscriber moves from the service area of one cell site to that of another by using automatic location confirmation and automatic radio channel conversion functions. The call state can be maintained continuously by the information exchange between switching systems when the busy subscriber moves from one Cellular system area to the other Cellular system area.

In the Cellular system, the cell site is a small-sized low output type and utilizes a frequency allocation system that considers mutual interference, in an effort to enable the re-use of corresponding frequency from a cell site separated more than a certain distance.

Unlike the time division multiple access (TDMA) or frequency division multiple access (FDMA) used in the band limited environment, the Code Division Multiple Access (CDMA) system which is one of digital Cellular systems is a multi-access technology under the interference limited environment. It can process more number of subscribers compared to other systems (TDMA system has the processing capacity three times greater than the existing FDMA system whereas CDMA system, about 12~15 times of that of the existing system).

CDMA system can be explained as follows; TDMA or CDMA can be used to enable each person to talk alternately or provide a separate room for each person when two persons desire to talk with each other at the same time, whereas FDMA can be used to enable one person to talk in soprano, whereas the other in bass (one of the two talkers can carry out synchronization for hearing in case there is a bandpass filter function in the area of the hearer). Another available method is to make two persons to sing in different languages at the same time, space, and frequency when wishing to let the audience hear the singing without being confused. This is the characteristic of CDMA.

On the other hand, when employing the CDMA technology, each signal has a different pseudo-random binary sequence used to spread the spectrum of carrier. A great number of CDMA signals share the same frequency spectrum. In the perspective of frequency area or time area, several CDMA signals are overlapped. Among these types of signals, only desired signal energy is selected and received through the use of pre-determined binary sequence; desired signals can be separated, and then received with the correlator used for recovering the spectrum into its original state. At this time, the spectrums of other signals that have different codes are not recovered into its original state, and appears as the self-interference of the system.

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CX8700

2. Features and Advantages of CDMA Mobile Phone

2.1 Various Types of Diversities

When employing the narrow band modulation (30kHz band) that is the same as the analog FM modulation system used in the existing Cellular system, the multi-paths of radio waves create a serious fading. However, in the CDMA broadband modulation (1.25MHz band), three types of diversities (time, frequency, and space) are used to reduce serious fading problems generated from radio channels in order to obtain hig h-quality calls. Time diversity can be obtained through the use of code interleaving and error correction code whereas frequency diversity can be obtained by spreading signal energy to wider frequency band. The fading related to normal frequency can affect the normal 200~300KHz among signal bands and accordingly, serious effect can be avoided. Moreover, space diversity (also called path diversity) can be realized with the following three types of methods. First, it can be obtained by the duplication of cell site receive antenna. Second, it can be obtained through the use of multi-signal processing device that receives a transmit signal having each different transmission delay time and then, combines them. Third, it can be obtained through the multiple cell site connection (Soft Handoff) that connects the mobile station with more than two cell sites at the same time.

2.2 Power Control

The CDMA system utilizes the forward (from a base station to mobile stations) and backward (from the mobile station to the base station) power control in ord er to in crease the call p ro cessing capacity an d ob tain h igh -q uality calls. In case the originating signals of mobile stations are received by the cell site in the minimum call quality level (signal to interference) through the use of transmit power control on all the mobile stations, the system capacity can be maximized.If the signal power of mobile station is received too strong, the performance of that mobile station is improved. However, because of this, the interference on other mobile stations using the same channel is increased and accordingly, the call quality of other subscribers is reduced unless the maximum accommodation capacity is reduced. In the CDMA system, forward power control, backward open loop power control, and closed loop power control methods are used. The forward power control is carried out in the cell site to reduce the transmit power on mobile stations less affected by the multi-path fading and shadow phenomenon and the interference of other cell sites when the mobile station is not engaged in the call or is relatively nearer to the corresponding cell site. This is also used to provide additional power to mobile stations having high call error rates, located in bad reception areas or far away from the cell site. The backward open loop power control is carried out in a corresponding mobile station; the mobile station measures power received from the cell site and then, reversely increases/decreases transmit power in order to compensate channel changes caused by the forward link path loss and terrain characteristics in relation to the mobile station in the cell site. By doing so, all the mobile transmit signals received by the base station have same strength. Moreover, the backward closed loop power control used by the mobile station is performed to control power using the commands issued out by the cell site. The cell site receives the signal of each corresponding mobile station and compares this with the pre-set threshold value and then, issues out power increase/decrease commands to the corresponding mobile station every 1.25msec (800 times per second). By doing so, the gain tolerance and the different radio propagation loss on the forward/backward link are complemented.

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CX8700

2.3 Voice Encoder and Variable Data Speed

The bi-directional voice service having variable data speed provides voice communication which employs voice encoder algorithm having power variable data rate between the base station and the mobile station. On the other hand, the transmit voice encoder performs voice sampling and then, creates encoded voice packets to be sent out to the receive voice encoder, whereas the receive voice encoder demodulates the received voice packets into voice samples. One of the two voice encoders described in the above is selected for use depending on inputted automatic conditions and message/data; both of them utilize four-stage frames of 9600, 4800, 2400, and 1200 bits per second for Cellular and 14400,7200,3600,1800 bits per second for PCS, so PCS provide relatively better voice quality (almost twice better than the existing celluar system). In addition, this type of variab le voice encoder utilizes adaptive threshold values on selecting required data rate. It is adjusted in accordance with the size of background noise and the data rate is increased to high rate only when the voice of caller is inputted. Therefore, background noise is suppressed and high-quality voice transmission is possible under the environment experiencing serious noise. In addition, in case the caller does not talk, data transmission rate is reduced so that the transmission is carried out in low energy. This will reduce the interference on other CDMA signals and as a result, improve system performance (capacity increased by about two times).

2.4 Protecting Call Confidentiality

Voice privercy is provided in the CDMA system by means of the private long code mask used for PN spreading. Voice privacy can ve applied on the traffic channels only. All calls are initiated using the public long code mask for PN spreading. The mobile station user may request voice privacy during call setup using the origination message or page response message, and during traffic channel operation using the long code transition request order. The Transition to private long code mask will not be performed if authentication is not performed. To initiate a transition to the private or public long code mask, either the base station or the mobile station sends a long code transition request order on the traffic channel.

2.5 Soft Handoff

A handoff in which the mobile station commences communications with a new base station without interrupting communications with the old base station. Soft handoff can only be used between CDMA channels having identical freqeuncy assignments.

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2.6 Frequency Re-Use and Sector Segmentation

Unlike the existing analog Cellular system, the CDMA system can reuse the same frequency at the adjacent cell. there is no need to prepare a separate frequency plan. Total interference generated on mobile station signals received from the cell site is the sum of interference generated from other mobile stations in the same cell site and interference generated from the mobile station of adjacent cell site. That is, each mobile station signal

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CX8700

generates interference in relation to the signals of all the other mobile stations . Total interference from all the adjacent cell sites is the ratio of interference from all the cell sites versus total interference from other mobile stations in the same cell site (about 65%). In the case of directional cell site, one cell normally uses a 120°sector antenna in order to divide the sector into three. In this case, each antenna is used only for 1/3 of mobile stations in the cell site and accordingly, interference is reduced by 1/3 on the average and the capacity that can be supported by the entire system is increased by three times.

2.7 Soft Capacity

The subscriber capacity of the CDMA system is flexible depending on the relation between the number of users and service classes. For example, the system operator can increase the number of channels available for use during the busy hour despite the drop in call quality. This type of function requires 40% of normal call channels in the standby mode during the handoff, in an effort to avoid call disconnection resulting from the lack of channels. In addition, in the CDMA system, services and service charges are classified further into different classes so that more transmit power can be allocated to high class service users for easier call set-up; they can also be given higher priority of using hand-off function than the general users.

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CX8700

3. Specification

3.1 General Specification

3.1.1 Transmit/Receive Frequency Interval :

1) CELLULAR : 45 MHz

2)

PCS : 80 MHz

3.1.2 Number of Channels (Channel Bandwidth)

1) CELLULAR : 20 Channels

2) PCS : 48 Channels

3.1.3 Operating Voltage : DC 3.3~4.2V

3.1.4 Battery Power Consumption : DC 3.7V

SLEEP IDLE MAX POWER

CELLULAR

PCS

1 mA 110~140mA 700 mA (24 dBm) 1 mA 120~150 mA 700 mA (24 dBm)

3.1.5 Operating Temperature : -20°C ~ +60°C

3.1.6 Frequency Stability

1) CDMA : ±0.5PPM

2) PCS : ±0.1PPM

3.1.7 Antenna : Intenna Type, 50 Ω

3.1.8 Size and Weight

1) Size : 97(H) * 49.5(W) * 13.6(D) mm

2) Weight : 110 g (Approximately with standard battery)

3.1.9 Channel Spacing

1) CELLULAR : 1.25MHz

2) PCS: 1.25 MHz

3.1.10 Battery Type, Capacity and Operating Time.

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Unit = Hours : Minutes

Standard (1,100mAh)

Standby Time

Talk time

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CELLULAR About 380 Hours (SCI=2)

PCS About 380 Hours (SCI=2)

CELLULAR 230 Minutes (-92dBm input)

PCS 230 Minutes (-92dBm input)

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CX8700

3.2 Receive Specification

3.2.1 Frequency Range

1) CELLULAR : 869.820 MHz ~ 893.190 MHz

2) PCS : 1930 MHz ~ 1990 MHz

3) GPS : 1575.42 MHz

3.2.2 Local Oscillating Frequency Range :

1) CELLULAR : 1738.08MHz ~ 1787.94MHz

2) PCS : 1715.56MHz ∼ 1768.89MHz

3) GPS : 3150.84MHz

3.2.3 Sensitivity

1) CELLULAR : -104dBm (C/N 12dB or more)

2) PCS : -104dBm (C/N 12dB or more)

3) GPS : -148.5dBm (without SA mode)

3.2.4 Selectivity

1) CELLULAR : 3dB C/N Degration (With Fch±1.25 kHz : -30dBm)

2) PCS : 3dB C/N Degration (With Fch±1.25 kHz : -30dBm)

3.2.5 Spurious Wave Suppression : Maximum of -80dB

3.2.6 CDMA Input Signal Range

z Dynamic area of more than -104~ -25 dB: 79dB at the 1.23MHz band.

3.3 Transmit Specification

3.3.1 Frequency Range

1) CELLULAR : 824.820MHz ~ 848.190MHz

2) PCS : 1850 MHz ~ 1910 MHz

3.3.2 Output Power

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1) CELLULAR : 0.224W

2) PCS: 0.224W

3.3.3 Interference Rejection

1) Single Tone : -30dBm at 900 kHz (CELLULAR), -30dBm at 1.25MHz(PCS)

2) Two Tone : -43dBm at 900 kHz & 1700kHz(CELLULAR), -43dBm at 1.25 MHz & 2.05 MHz (PCS)

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CX8700

3.3.11 CDMA TX Frequency Deviation :

1) CELLULAR: +300Hz or less

2) PCS: ± 150Hz

3.3.12 CDMA TX Conducted Spurious Emissions

1) CELLULAR : 900kHz : - 42 dBc/30kHz below

1.98MHz : - 54 dBc/30kHz below

2) P C S : 1.25MHz : - 42 dBc/30kHz below

1.98MHz : - 50 dBc/30kHz below

3.3.13 CDMA Minimum TX Power Control

1) CELLULAR : - 50dBm below

2) P C S : -50dBm below

3.4

MS (Mobile Station) Transmitter Frequency

3.4.1 CELLULAR mode

Ch # Center Freq. (MHz) Ch # Center Freq. (MHz)

1011

29

70 111 152 193 234 275 316 363

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824.640

825.870

827.100

828.330

829.560

830.790

832.020

833.250

834.480

835.890

404 445 486 527 568 609 650 697 738 779

837.120

838.350

839.580

840.810

842.040

843.270

844.500

845.910

847.140

848.370

3.4.2 PCS mode

Ch # Center Freq (MHz) Ch # Center Freq (MHz) Ch # Center Freq (MHz)

25 1851.25 425 1871.25 825 1891.25 50 1852.50 450 1872.50 850 1892.50

75 1853.75 475 1873.75 875 1893.75 100 1855.00 500 1875.00 900 1895.00 125 1856.25 525 1876.25 925 1896.25 150 1857.50 550 1877.50 950 1897.50

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CX8700

175 1858.75 575 1878.75 975 1898.75 200 1860.00 600 1880.00 1000 1900.00 225 1861.25 625 1881.25 1025 1901.25 250 1862.50 650 1882.50 1050 1902.50 275 1863.75 675 1883.75 1075 1903.75 300 1865.00 700 1885.00 1100 1905.00 325 1866.25 725 1886.25 1125 1906.25 350 1867.50 750 1887.50 1150 1907.50 375 1868.75 775 1888.75 1175 1908.75

3.5

MS (Mobile Station) Receiver Frequency

3.5.1 CELLULAR mode

Ch. # Center Freq. (MHz) Ch. # Center Freq. (MHz)

1011

29

70 111 152 193 234 275 316 363

3.5.2 PCS mode

869.640

870.870

872.100

873.330

874.560

875.790

877.020

878.250

879.480

880.890

404 445 486 527 568 609 650 697 738 779

882.120

883.350

884.580

885.810

887.040

888.270

889.500

890.910

892.140

893.370

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Ch # Center Freq (MHz) Ch # Center Freq (MHz) Ch # Center Freq (MHz)

25 1931.25 425 1951.25 825 1971.25 50 1932.50 450 1952.50 850 1972.50

75 1933.75 475 1953.75 875 1973.75 100 1935.00 500 1955.00 900 1975.00 125 1936.25 525 1956.25 925 1976.25 150 1937.50 550 1957.50 950 1977.50 175 1938.75 575 1958.75 975 1978.75 200 1940.00 600 1960.00 1000 1980.00

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CX8700

225 1941.25 625 1961.25 1025 1981.25 250 1942.50 650 1962.50 1050 1982.50 275 1943.75 675 1963.75 1075 1983.75 300 1945.00 700 1965.00 1100 1985.00 325 1946.25 725 1966.25 1125 1986.25 350 1947.50 750 1967.50 1150 1987.50 375 1948.75 775 1968.75 1175 1988.75

3.5.3 GPS mode : 1575.42 MHz

3.5.4 Bluetooth mode : 2400 MHz ~ 2483.5 MHz

3.6 AC Adaptor : See Appendix

3.7 Cigar Lighter Charger : See Appendix

3.7 Hands – Free Kit : See Appendix

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CX8700

4. Installation

4.1 Installing a Battery Pack

1) The Battery pack is keyed so it can only fit one way. Align the groove in the battery pack with the rail on the back of the phone until the battery pack rests flush with the back of the phone.

2) Slide the battery pack forward until you hear a “click”, which locks the battery in place.

4.2 For Adapter Use

1) Plug the adapter into a wall outlet. The adapter can be operated from a 110V source. When AC power is connected to the adapter.

2) Insert the adapter IO plug into the phone with the installed battery pack.

Red light indicates battery is being charged.. Green light indicates battry is fully charged.

4.3 For Mobile Mount

4.3.1 Installation Position

In order to reduce echo sound when using the Hands-Free Kit, make sure that the speaker and microphone are not facing each other and keep microphone a generous distance from the speaker.

4.3.2 Cradle Installation

Choose an appropriate flat surface where the unit will not interface with driver’s movement or passenger’s comfort. The driver/user should be able to access the phone with ease. Using the four self-tapping screws provided, mount the supplied braket on the selected area. Then with the four machine screws provided, mount the counterpart on the reverse side of the reverse side of the cradle. Secure the two brackets firmly together by using the two bracket joint screws provide. The distance between the cradle and the interface box must not exceed the length of the main cable.

4.3.3 Interface Box

Choose an appropriate flat surface ( somewhere under the dash on the passenger side is preferred ) and mount the IB bracket with the four self-tapping screws provided. Clip the IB into the IB bracket.

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4.3.4. Microphone Installation

Install the microphone either by cliiping I onto the sunvisor (driver’s side) or by attaching it to door post (driver’s side), using a velcno adhesive tape (not included).

4.3.5 Cable Connections

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CX8700

4.3.5.1 Power and Ignition Cables

Connect the red wire to the car battery positive terminal and the black wire to the car ground. Connect the green wire to the car ignition sensor terminal. ( In order to operate HFK please make sure to connect green wire to ignition sensor terminal.) Connect the kit’s power cable connector to the interface box power receptacle.

4.3.5.2 Antenna Cable Connection

Connect the antenna coupler cable connector from the cradle to the external antenna connector. ( Antenna is not included.)

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CHAPTER 2. NAM Input Method

(Inputting of telephone numbers included)

1. NAM Program Method and Telephone Number Inputting Method

1. In idle state, Press ‘##83587’ + “000000”

2. Select ‘1.NAM1’ or ‘2.NAM2’ to see each parameter. (Except ESN)

● Usually pressing ‘OK key’ will save the change.

● To exit Service Program, press ‘END’ key.

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2-1) NAM1 Setting

After select ‘1.NAM1’, you can see this Entrance screen for for NAM1 setting. Press ‘OK key’ to edit NAM1 items. Press ‘CLR key’ to go to the main page. (NAM2 settingwill show you same screen when you select ‘2.NAM2’)

2-2) NAM1 Phone Number (MDN)

You can edit NAM1 Phone Number(MDN). Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

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2-3) NAM1 Phone Number (MIN)

You can edit NAM1 Phone Number(MIN). Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

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2-4) NAM1 Home SID

You can edit NAM1 Home SID. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-5) NAM1 Name

You can edit NAM1 Name. Press ‘OK’ to edit more NAM1 items. Press ‘Soft Key 1’ to edit NAM1 Name. Press ‘CLR key’ to edit previous NAM1 items.

2-6) More NAM1 Programming

You can decide to edit more NAM1 items. Press ‘END key’ to exit Service Programming. Press ‘OK key’ to edit more advanced NAM1 items.

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2-7) NAM1 MCC

You can edit NAM1 Mobile Country Code. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-8) NAM1 MNC

You can edit NAM1 MNC. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-9) NAM1 NMSID

You can edit NAM1 MNC. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

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2-10) NAM1 True IMSI MCC

You can edit NAM1 True IMSI MCC. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-11) NAM1 True IMSI NMSID

You can edit NAM1 True IMSI NMSID. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-12) NAM1 PRL Enabled

You can see NAM1 PRL Enabled. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

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2-13) CDMA Home SID/NID

You can edit NAM1 Home SID/NID Pairs. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-14) NAM1 CDMA Pri. CH A

You can edit NAM1 CDMA Primary Channel A. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

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2-15) NAM1 CDMA Sec. CH A

You can edit NAM1 CDMA Secondary Channel A. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

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2-16) NAM1 CDMA Pri. CH B

You can edit NAM1 CDMA Primary Channel B. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-17) NAM1 CDMA Sec. CH B

You can edit NAM1 CDMA Secondary Channel B. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-18) Lockout SID/NID

You can edit Lockout SID/NID Pairs. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

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2-19) NAM1 Home Sys Reg

You can edit Home System Registration. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items. Press Left, Right, Up, Down key to toggle Yes/No.

2-20) NAM1 Forn SID Reg

You can edit NAM1 Foreign SID Registration. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items. Press Left, Right, Up, Down key to toggle Yes/No.

2-21) NAM1 Forn NID Reg

You can edit NAM1 Foreign NID Registration. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items. Press Left, Right, Up, Down key to toggle Yes/No.

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2-22) NAM1 Acc Ovld Class

You can see NAM1 Access Overload Class. Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-23) Slot Cycle Index

You can edit Slot Cycle Index Press ‘OK key’ to edit more NAM1 items. Press ‘CLR key’ to edit previous NAM1 items.

2-24) Powering Down

Restart.

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2-25) ESN

You can see the ESN number by select ‘3.View ESN’ from Service Programing main menu. It will be shown as decimal format. ESN can’t be modified.

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CX8700

CHAPTER 3. Circuit Description

1. RF Transmit/Receive Part

1.1 Overview

The TX and RX part employs the Direct-Conversion system. The TX and RX frequencies are respectively 824.04~848.97 and 869.04~893.97 for cellular and 1850~1910 and 1930~1990 for PCS. The block diagram is shown in [Figure 1-1]. RF signals received through the antenna are seperated by the Triplexer. RF Signal fed into the low noise amplifier in RFR6500(LNA) through the duplexer. Then, they are fed into Mixer in RFR6500. In RFR6500, the RF signal is changed into baseband signal directly. Then, this signal is changed into digital signal by the analog to digital converter (ADC, A/D Converter), and the digital circuit part of the MSM(Mobile Station Modem) 6500 processes the data from ADC. The digital processing part is a demodulator. In the case of transmission, RFT6150 receives OQPSK-modulated anlaog signal from the MSM6550. The RFT6150 connects directly with MSM6550 using an analog baseband interface. In RFT6150, the baseband quadrature signals are upconverted to the Cellular or PCS frequency bands and amplified to provide signal drive capability to the power amp. After that, the RF signal is amplified by the Power Amp in order to have enough power for radiation. Finally, the RF signal is sent out to the cell site via the antenna after going through the duplexer.

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CX8700

[Figure 1-1] Block Diagram of CX8700

Tri-band Ant.

U103

Mobile S/W

MS-156NB

Triplexer

GPS BPF

U104

Triplexer

C015

PCS Duplexer

ACMD-7402

DCN Duplexer

EFSD836MF2S2

DP101

U109

COUPLER

CP0402A1880

U110

COUPLER

CP0402A836

DP104

U107

GPS LNA

ALM-1106-TR1

U108

DUAL PAM

AWT6310R Gain:27dB

Gain:15.9dB

NF:1.6dB

Gain:15.4dB

NF:1.4dB

Gain:15.4dB

NF:1.4dB

F104

PCS Tx RF BPF

ACPF -7002

IL:3.5dB

Attn.:35dB

F105 DCN Tx RF SAW EFCH836MT CB 8

IL:2.5dB

Attn.:39dB

F102

PCS Rx RF SAW

B7847

IL:3.4dB

GPS Rx RF SAW

DCN Rx RF SAW EFCH881MT CA7

IL:2.5dB

F103

B7840

F101

RFR6500

RFR6000

U105

RFT6150

TX PLL

Loop Filter

LO Distribution

Loop Filter

U102

Loop Filer

RX PLL

GPS PLL

Gain Control

X101

VCTCXO

TG-5010LH

LPF

Secondary path

Jammer Det.

SBI 1

SBI 2

Primary path

M

S

M

6 5 5 0

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CX8700

BLUETOOTH

RF

MODULE

RFT6150

VCTCXO

RFR6500

BT 1.2 PROCESS

JTAG Interface

ARM9 Core

R-UIM Controller

RF Interface

MSM6550

DFM processor

CDMA processor

gpsOne processor

Memory Controller

QDPS4000

- VOCODER

- MIDI(CMX) etc.

HK ADC

SBI

Tx DACs

PLL

Rx ADCs

CODEC

USB

GPIO

T-Flash MEMORY

CAMERA Module

2M Pixels

LCD MODULE

262K TFT Main

65K TFT Sub

PMIC

MAX1829

Battery

MCP MEMORY

1G NAND Flash

512M SDRAM

(TY9000A000AMGP)

KEYPAD

Mic

EARPIECE

Stereo SPK

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AUDIO AMP

(LM4857)

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CX8700

1.2 Description of RX Part Circuit

1.2.1 Triplexer Filter (U104)

The main function of Triplexer is to prohibit the other band signals from flowing into the one band circuit and vice versa. RF designer can use common tri-band antenna regardless of frequency band (800, 1575 and 1900 MHz). The specification of CX8700 Triplexer is described below:

Cellular GPS PCS

Frequency Range 824 – 894 MHz 1575.42 MHz 1850 – 1990 MHz

Insertion Loss to

Common

Isolation

Temperature Range -30 to +85 deg

1.2.2 Duplexer (DP104, DP101)

1.0 dB Max

(At +25 deg)

48.5dB

(Cell TX)

1.8 dB Max.

(At +25 deg)

32.9dB(GPS-Cell)

18.3(GPS-PCS)

0.85 dB Max (At +25 deg)

53.1dB

(PCS TX)

The duplexer consists of the RX bandpass filter (BPF) and the TX BPF which has the function of separating TX and RX signals in the full duplex system for using the common antenna. The TX part BPF is used to suppress noises and spurious out of the TX frequency band. The RX BPF is used to receive only RX signal coming from the antenna, which is usually called preselector. It’ s main function is to limit the bandwidth of spectrum reaching the LNA and mixer, attenuate receiver spurious response and suppress local oscillator energy. As a result frequency sensitivity and selectivity of mobile phone increase. The specification of CX8700 duplexer described below ;

z PCS duplexer:

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TX RX TX to RX (min)

Pass Band 1850~1910 MHz 1930~1990 MHz

Insertion Loss 3.5dB max 3.0dB max

Return Loss 8.0dB min 8.0dB min

Attenuation

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(1930~1990MHz)

40dB min

50dB min

(1850~1910MHz)

54dB (1850~1910MHz)

44dB (1930~1990MHz)

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CX8700

z Cellular duplexer

TX RX TX to RX (min)

Pass Band 824~849 MHz 869~894 MHz

Insertion Loss 2.5B max 3.5dB max

VSWR 2.2 max 2.3 max

Attenuation 40dB min (869~894MHz)

1.2.3 LNA (U105)

The RFR6500 has cellular, and PCS LNA, respectively. The characteristics of Low Noise Amplifier (LNA) are low noise figure, high gain, high intercept point and high reverse isolation. The frequency selectivity characteristic of mobile phone is mostly determined by LNA. The specification of CX8700 LNA is described below:

Parameter

Gain -19 -20 -2 -9 15.5 16 dB Noise Figure 19 20 2 9 1.4 1.6 dB Input IP3 25 25 20 20 6 8 dBm

1.2.4 GPS LNA(U107)

Low gain Middle gain High gain Units

Cellular PCS Cellular PCS Cellular PCS

50dB min

(824~849MHz)

54dB (824~849MHz)

43dB (869~894MHz)

The characteristics of Low Noise Amplifier (LNA) are low noise figure, high gain, high intercept point and high reverse isolation. The frequency selectivity characteristic of mobile phone is mostly determined by LNA. The specification of CX8700 GPS LNA is described below

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Parameter GPS Band Units

Gain 14.8 dB

Noise Figure 0.85 dB

1dB compression point 0 dBm

IIP3 +5 dBm

1.2.5 RX RF SAW FILTER(F101, F102, F103)

The main function of RX RF SAW filter is to attenuate mobile phone spurious frequency, attenuate noise amplified by the LNA and suppress second harmonic originating in the LNA.

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CX8700

1.2.6 Down-converter Mixers (U105)

The RFR6500 device performs signal down-conversion for Cellular, PCS and GPS tri-band applications. It contains all the circuitry (with the exception of external filters) needed to support conversion of received RF signals to Base-band signals. The three down-converting Mixers (Cellular, PCS and GPS), and a programmable PLL for generating RX LO frequency and an RX LO Buffer Amplifier and RX Voltage Controlled Oscillator. The GPS LNA & mixers offer the most advanced and integrated CDMA RX solution designed to meet cascaded Noise Figure (NF) and Third-order Intercept Point (IIP3) requirements of IS-98D and J-STD-018 specifications for Sensitivity, Two-Tone Inter-modulation, and Single-tone Desensitization. Operation modes and band selection are specially controlled from the Mobile Station Modem MSM6550. The specification of CX8700 Mixers is described below:

Parameter

Noise Figure 27 27 11 11 dB Input IP3 4 3 4 3 dBm Input IP2 50 50 75 70 dBm

Low gain High gain Units

Cellular PCS Cellular PCS

1.3 Description of Transmit Part Circuit

1.3.1 RFT6150 (U102)

The RFT6150 Base-band to RF Transmit Processor performs all TX signal-processing functions required between digital Base-band and the Power Amplifier Modulator (PAM). The Base-band quadrate signals are up-converted to the Cellular or PCS frequency bands and amplified to provide signal drive capability to the PAM. The RFT6100 includes an mixers for up-converting analog Base-band to RF, a programmable PLL for generating TX LO frequency an TX LO Buffer Amplifier and TX Voltage Controlled Oscillator, cellular and PCS driver

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amplifiers and TX power control through an 85 dB VGA. As added benefit, the single sideband up-conversion eliminates the need for a band pass filter normally required between the up-converter and driver amplifier. I, I/, Q and Q/ signals proceed from the MSM6550 to RFT6150 are analog signal. In CDMA mode, These signals are modulated by Offset Quadrature Phase Shift King (OQPSK). I and Q are 90 deg. out of phase, and I and I/ are 180 deg. The mixers in RFT6150 converts baseband signals into RF signals. After passing through the upconverters, RF signal is inputted into the Power AMP.

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CX8700

z RFT6150 Cellular and PCS CDMA RF Specifications

Parameter Condition Min. Type. Max. Units

Rated Output Power

Min Output Power

RX band noise power

ACPR

Average CDMA Cellular

Average CDMA PCS

Average CDMA Cellular

Average CDMA PCS

CDMA Cellular

CDMA PCS

Cellular: Fc±885kHz

PCS : Fc±1.25MHz

8

10

-80

-78

-133

-132

-56

dBm dBm dBm dBm

dBm/Hz

dBc/

30kHz

1.3.2 Power Amplifier(U108)

The Dual power amplifier that can be used in the PCS and CDMA mode has linear amplification capability and high efficiency. For higher efficiency, it is made up of one MMIC (Monolithic Microwave Integrated Circuit) for which RF input terminal and internal interface circuit are integrated onto one IC after going through the AlGaAs/GaAs HBT (heterojunction bipolar transistor) process. The module of power amplifier is made up of an output end interface circuit including this MMIC. The maximum power that can be inputted through the input terminal is +17dBm and conversion gain is about 28dB. RF transmit signals that have been amplified through the power amplifier are sent to the duplexer. .

1.4 Description of Frequency Synthesizer Circuit

1.4.1 Voltage Control Temperature Compensation Crystal Oscillator (VCTCXO, X101)

The temperature variation of mobile phone can be compensated by VCTCXO. The reference frequency of a mobile phone is 19.2 MHz. The receiver frequency tuning signals called TRK_LO_ADJ from MSM as 0.5 V~2.5 V DC via R and C filter in order to generate the reference frequency of 19.2 MHz and input it into the frequency synthesizer. Frequency stability depending on temperature is ±2.0 ppm.

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CX8700

2. Digital/Voice Processing Part

2.1 Overview

The digital/voice processing part processes the user's commands and processes all the digital and voice signal processing in order to operate in the phone. The digital/voice processing part is made up of a keypad/LCD, receptacle part, voice processing part, mobile station modem part, memory part, and power supply part.

2.2 Configuration

2.2.1 Keypad/LCD and Receptacle Part

This is used to transmit keypad signals to MSM6550. It is made up of a keypad backlight part that illuminates the keypad, LCD part that displays the operation status onto the screen, and a receptacle that receives and sends out voice and data with external sources.

2.2.2 Voice Processing Part

The voice processing part is made up of an audio codec used to convert MIC signals into digital voice signals and digital voice signals into analog voice signals, amplifying part for amplifying the voice signals and sending them to the ear piece, amplifying part that amplifies ringer signals coming out from MSM6550, and amplifying part that amplifies signals coming out from MIC and transferring them to the audio processor.

2.2.3 MSM (Mobile Station Modem) 6500 Part

MSM is the core elements of CDMA terminal and carries out the functions of CPU, encoder, interleaver, deinterleaver, Viterbi decoder, Mod/Demod, and vocoder.

2.2.4 Memory Part

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The memory part is made up of a NAND Flash memory and a SDRAM for storing data.

2.2.5 Power Supply Part

The power supply part is made up of circuits for generating various types of power, used for the digital/voice processing part.

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CX8700

2.3 Circuit Description

2.3.1 Keypad/LCD and Receptacle Part

Once the keypad is pressed, the key signals are sent out to MSM6550 for processing. In addition, when the key is pressed, the keypad/LCD lights up through the use of 18 LEDs. The terminal status and operation are

displayed on the screen for the user with the characters and icons on the LCD. Moreover, it exchanges audio signals and data with external sources through the receptacle, and then receives power from the battery or external batteries.

2.3.2 Audio Processing Part

MIC signals are amplified through OP AMP, inputted into the audio codec(included in MSM6550) and converted into digital signals. Oppositely, digital audio signals are converted into analog signals after going through the audio codec. These signals are amplified at the audio amplifier and transmitted to the ear-piece. The signals from MSM6550 activate the ringer by using signals generated in the timer in MSM6550.

2.3.3 MSM Part

MSM6550 is the core element of CDMA system terminal that includes ARM926EJ-S microprocessor core. It supports both CDMA and Digital FM, operating in both the cellular and PCS spectrums. The subsystems within the MSM6550 include a CDMA processor, a DFM processor, a multi-standard Vocoder, an integrated CODEC with earpiece and microphone amplifiers, general-purpose ADC for subsytem monitoring, an ARM926EJ-S microprocessor, and an RS-232 serial interfaces supporting forward and reverse link MDR data communications of 230.4 Kbps simultaneously. And it also contains complete digital modulation and demodulation systems for both CDMA and AMPS cellular standards, as specified in IS-95-A/B/C. In MSM, coded symbols are interleaved in order to cope with multi-path fading. Each data chann el is scrambled by the long code PN sequence of the user in order to ensure the confidentiality of calls. Moreover, binary quadrature codes are used based on walsh functions in order to discern each channel. Data created thus are 4-phase modulated by one pair of Pilot PN code and they are used to create I and Q data. When received, I and Q data are demodulated into symbols by the demodulator, and then de-interleaved in reverse to the case of transmission. Then, the errors of data received from viterbi decoder are detected and corrected. They are voice-decoded at the vocoder in order to output digital voice data.

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CX8700

B/T Chip

B/T Chip Antenna

Antenna

RFR6000

RFR6500

POWER

POWER Amplifier

Amplifier

VCTCXO

+2.9V_Rx_LDO

RFT6100

RFT6150

Bluetooth RF

19.2MHz

INNER CHG

BATTERY

HDET

RF Controls

Bluetooth

Bluetooth Baseband

Baseband Processor

Processor

PLL

HK ADC

Rx

ADCs

RF

Interface

TX

DACs

AUX

SBI

MSM6500

Mobile Station Modem

gpsOne

Processor

CDMA

Processor

DFM

Processor

JTAG Interfaces

UART1

UART1 UART2

UART2

UART3/USB

Integrated

MODE Select

Interface

ETM

CAMIF

ARM9

TDMI

Memory

Controller

General-

Purpose

Interface

Vocoder

EVRC

13k

13k MP4

MP4

MIDI

QDSP4000

CODEC

Data Comm

DM

USB

Transceiver

LDO

Camera module

Camera module (1.3M C-MOS)

(1.3M C-MOS)

Microprocessor Bus

Address/Data

General-Purpose Interface Bus

1 2 3

1 2 3 4 5 6

Keypad input

2

4 5 6 7 8 9

7 8 9 * #0

* #0

Audio AMP

EAR

MIC

Digital Test Bus JTAG

PC

Connectivity

Test/Debug

System

Memory

NAND Flash(512Mb)

LP-SDRAM(256Mb)

LP-SDRAM(512Mb)

KEYPAD, BEZEL,

SIIDEKEY

Speaker

External

EAR/MIC

LCD

Peripheral Circuits

[Figure 2-2] Block Diagram of Digital/Voice Processing Part

2.3.4 Memory Part

MCP contents 512Mbits NAND FLASH memory and 256Mbits SDRAM. In the NAND Flash Memory part of MCP are programs used for terminal operation. The programs can be changed through downloading after the assembling of terminals. On the SDRAM data generated during the terminal operation are stored temporarily.

2.3.5 Power Supply Part

When the battery voltage (+4.0V) is fed and the PWR key of keypad is pressed, U402(PMIC) is activated by the PWR_ON_SW signal, and The PWRON signal is held high, Buck and LDO1,2,3 are turned on; when LDO1 reaches 87% of its final value a 60ms reset timer is started at after which RESET\ is asserted high. Now the BB Processor is initialized and will assert PWRHOLD high. PWRHOLD maintains the power on.

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The Buck/LDO1,2,3 are generating the +1.4V_MSMC, +2.6V_MSMA, +1.8V_MSMP1 and +2.8V_LCD respectively. The Rx part LDO(Out5) is operated by the control signal SLEEP/ from MSM6550 The Tx part LDO(Out7) is operated by the control signal IDLE/ from MSM6550. The TCXO part LDO(U403) is operated by the control signal TCXO_EN/ from MSM6550.

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CX8700

2.3.6 Logic Part

The logic part consists of internal CPU of MSM, RAM, MCP. The MSM6550 receives TCXO (=19.2MHz) from the X101 and controls the phone in CDMA modes. The major components are as follows:

z

The ARM926J-S microprocessor includes a 3 stage pipelined RISC architecture, both 32-bit ARM and 16-bit THUMB instruction sets, a 32-bit address bus, and a 32-bit internal data bus. It has a high performance and low power consumption.

CPU

z

NAND Flash is used to store the terminal’s program. Using the down-loading program, the program can be changed even after the terminal is fully assembled.

SDRAM is used to store the internal flag information, call processing data, and timer data.

z

For key recognition, key matrix is setup using KYPD[1][3][5][7][9][11][13][15][17][19][21] signal from MSM6550. 18 LEDs and backlight circuitry are included in the keypad for easy operation in the dark.

z

LCD module contains a controller which will display the information onto the LCD by 16-bit data from the

MSM6550. It is also supplied stable +2.8V_LCD by Out3 in U402 for fine view angle and LCD reflects to

improve the display efficiency. 4 LEDs is used to display LCD backlight.

MCP

KEYPAD

LCD MODULE

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CX8700

R

p

ply

CHAPTER 4. Trouble Shooting

4.1.1 DCN Rx

Test Point

DCN_Duplexer

Mobile S/W

Triplexer

PCS_Duplexer

RFR6500

VCTCXO

Checking Flow

START

x

TE

ST SETUP (HHP)

- Test Channel: 384

- Test Band:

- SID: 2004

- S Spec Oscilloscope Setting

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US Ce

llular

ecto

r Power: -30 dBm

trum Analyzer Setting

1. Check

DC P

owe

r su

circuit

2. Check

VCTCXO Circuit

3. Check

Co

ntrolsignal

4. Check

RFSign

alpath

5. Check

Rx I

/Qdata

e

downloadSW, CAL

LG Electronics Inc.

- 37 -

CX8700

YesY

Y

4.1.1.1 Checking DC Power supply Circuit (PMIC)

Test Point Checking Flow

U302, U303

Check R319

of U303

Check MSMP2

Check L412

of U303

+2.9V_

RX0 sOK?

No

+2.6V_

MSMP2

is OK

es

+2.9V_

es

DC Powe is OK. See next Page

No

RX0isOK?

No

r supply Circuit

The Problem may Refer to Logic trou

?

The Problem may Refer to Logic trou

to

be Logic

blesh

oot

be Logic

blesh

be Logic

blesh

par

oot

t

par

t

Circuit Diagram

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LG Electronics Inc.

- 38 -

CX8700

g V

T

Refer t

t

r

VCTCX

r

)

r

)

4.1.1.2 Checkin

Test Point

CTCXOCircuit

Check X101 Pin 3

◆ Refe

Check X101 Pin 4

◆ Refe

X101

to Graph 4.1.1(a

to Graph 4.1.1(b

Changing X101 Check R125, R127 C1002

SW Download Replace Boa

19.2MHz ?

+2.8V OK?

YES

Simila

Checking Flow (VCTCXO)

No

?

NO

YES

NO

YES

d

VCTCXO

ne

Control signal

be Logic

S Control signal

Ci

xt Page to

he Problem may

ee next Page to check

rcuit is OK.See

check

part

o Logic

O

Ci

rcuit is OK.

ou

blesh

oot

Waveform

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Graph Graph

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- 39 -

CX8700

Circuit Diagram

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LG Electronics Inc.

- 40 -

CX8700

r

4.1.1.3 Checking Control signal

Test Point

U105 Pin49 (SBST0) Pin50 (SBDT0)

Check Pin 49(SBCK0),

Check if there is Any Major Difference

Refer to Graph 4.1.1(

◆

Check Pin 49(SBCK0),

Check if there is Any Major Difference

◆

Refer to Graph 4.1

.1(

Checking Flow

Pin 50(SBST0) Pin 51(SBDT0) of U105

c,d

)

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Pin 50(SBST0) Pin 51(SBDT0) of U105

c,d

)

Similar?

Download the SW

Replace Board

Simila

NO

?

YES

Control Signal is Ok

See next Page to Check

RF signal path

Control Signal is Ok

See next Page to Check

RF signal path

LG Electronics Inc.

- 41 -

CX8700

SB

CK0

Waveform

SB

CK0

SB

ST0

Graph 4.1.1(c)

SB

DT0

Circuit Diagram

Graph 4.1.1(d)

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LG Electronics Inc.

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CX8700

A

◆Refer toGra

p

(e)

A

4.1.1.4 Checking RF Signal path (Mobile S/W, Triplexer, Duplexer)

DP101. Pin3

U104. Pin7

C1034, L111 C173

Test Point Checking Flow

U103. Pin2

DP101

U104

C1063, L185

Check U103 Pin 2

Check

if ther

e is

ny Major Difference

h 4.1.1

Check U104 Pin 7

Check

if ther

e is

ny Major Difference

◆

Ref

er to Grap

Check DP101 Pin 3

Check

if ther

ny Major Difference

◆

Ref

er to Grap

e is

h 4.1.1(f)

h 4.1.1(g)

No

Changing U104

Changing U103

Check C101

Check C1063&L185

Changing DP101

Detected S

ignal?

Yes

ignal?

Yes

ignal?

Yes

ignal?

Yes

ignal?

Yes

No

Check C1034 & C173

L111

Detected S

RF Signal Path

S

ee next Page to check

RX I/Q data signal

ignal?

Yes

is

OK.

.

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LG Electronics Inc.

- 43 -

CX8700

)

U103 Pin

Waveform

Graph 4.1.1(e

U104 Pin

DP101 Pin 3

Graph 4.1.1(f)

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Graph 4.1.1(g)

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CX8700

Circuit

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LG Electronics Inc.

- 45 -

CX8700

r

rd A

d

,

A

)

4.1.1.5 Checking Rx I/Q data

Test Point

U105 Pin7 (RX0_QM Pin8 (RX0_QP) Pin9 (RX0_IM) Pin10 (RX0_IP)

Check Pin7 (RX0_QM) Pin8 (RX0_QP) Pin9 (RX0_IM) Pin10 (RX0_IP)

Check if there is

ny Major Difference

◆ Refer to Graph 4.1.1(h,i)

Check Pin7 (RX0_QM) Pin8 (RX0_QP) Pin9 (RX0_IM) Pin10 (RX0_IP)

Check if there is

ny Major Difference

◆ Refer to Graph 4.1.1(h,i)

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Checking Flow

Simila

?

Yes

Re-download the

e & Calibrate

Softwa

Similar?

Yes

ll DCN RX check is complete if the phone still does not work change the board.

No

Replace U105

No

Replace Boa

LG Electronics Inc.

- 46 -

CX8700

)

Waveform

RX0_IP

RX0_IM

Graph 4.1.1(h)

RX0_QP

RX0_QM

Graph 4.1.1(i

Circuit

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LG Electronics Inc.

- 47 -

CX8700

X

R

L

R

p

ply

4.1.2 PCS R

Test Point

Checking Flow

START

x

TE

ST SETUP (HHP)

- Test Channel: 600

- Test Band:

- SID: 4119

- S Spec Oscilloscope Setting

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US

PCS

ecto

r Power: -30 dBm

trum Analyzer Setting

1. Check

DC P

owe

r su

circuit

3. Check

Co

ntrolsignal

4. Check

RFSign

alpath

2. Check

VCTCXO Circuit

5. Check

Rx I

/Qdata

e

LG Electronics Inc.

-downloadSW, C

A

- 48 -

CX8700

T

Y

4.1.2.1 Checking DC Power supply Circuit (PMIC)

Test Point Checking Flow

Circuit Diagram

Check R319

of U303

Check C318

of U302

+2.9V_

RX0 isOK?

es

+2.6V_

es

DC Powe is OK. See next Page

No

MSMP2

is OK

No

r supply Circuit

The Problem may Refer to Logic trou

?

he Problem may

Refer to Logic trou

to

be Logic

blesh

oot

be L

blesh

par

t

ogicpart

oot

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LG Electronics Inc.

- 49 -

CX8700

T

Refer t

t

r

VCTCX

r

(b)

(a)

4.1.2.2 Checking VCTCXOCircuit

Test Point Checking Flow (VCTCXO)

Waveform

Check X101 Pin 3

◆ Refer to Graph

4.1.2

?

Check X101 Pin 4

◆ Refer to Graph

4.1.2

?

19.2MHz?

+2.9V OK?

YES

Changing X101 Check C1001, C1002, C1006, R125

?

Simila

NO

SW Download Replace Boa

d

YES

NO

YES

VCTCXO ne Control signal

be Logic

S Control signal.

Ci

xt Page to

he Problem may

ee next Page to check

rcuit is OK.See

check

.

part

o Logic

O

Ci

rcuit is OK.

ou

blesh

oot

Z3X-BOX.COM

Graph Graph

LG Electronics Inc.

- 50 -

CX8700

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 51 -

CX8700

r

4.1.2.3 Checking Control signal

U105 Pin49 (SBST0) Pin50 (SBDT0)

Test Point

Check Pin 49(SBCK0),

Pin 50(SBST0) Pin 51(SBDT0) of U105

Check if there is Any Major Difference

◆

Refer to Graph 4.1.2(

Z3X-BOX.COM

Check Pin 49(SBCK0),

Pin 50(SBST0) Pin 51(SBDT0) of U105

Check if there is Any Major Difference

◆

Refer to Graph 4.1.2(

Checking Flow

c,d

)

Download the SW

c,d

)

Replace Board

Similar?

Simila

NO

?

NO

YES

Control Signal is Ok

See next Page to Check

RF signal path

Control Signal is Ok

See next Page to Check

RF signal path

LG Electronics Inc.

- 52 -

CX8700

SB

CK0

Waveform

SB

CK0

SB

Graph 4.1.2(c)

ST0

SB

DT0

Circuit Diagram

Graph 4.1.2(d)

Z3X-BOX.COM

LG Electronics Inc.

- 53 -

CX8700

r

A

◆Refer toGra

p

(e)

A

4.1.2.4 Checking RF Signal path (Mobile S/W, Triplexer, Duplexer)

C101

U104

U109

DP101

Test Point Checking Flow

U103

Check U103 Pin 1

Check

if ther

ny Major Difference

Check U104 Pin 7,

if ther

Ref

er to Grap

if ther

Ref

er to Grap

U109 Pin4

Check

ny Major Difference

◆

Check DP101 Pin 2

Check

ny Major Difference

◆

e is

h 4.1.2

h 4.1.2(f)

h 4.1.2(g)

Detected S

ignal?

Yes

ignal?

Yes

ignal?

Yes

ignal?

Yes

ignal?

Yes

ignal?

No

Changing U107

No

Check C101

No

Changing U104 o U109

No

Check C131&C192& C1062

No

Changing DP101

No

Check C1055 & C153

Yes

RF Signal Path

S

ee next Page to check

RX I/Q data signal

is

OK.

.

Z3X-BOX.COM

LG Electronics Inc.

- 54 -

CX8700

)

U103 Pin

Waveform

Graph 4.1.2(e

U104 Pin

DP101 Pin

Graph 4.1.2(f

Z3X-BOX.COM

LG Electronics Inc.

Graph 4.1.2(g

- 55 -

CX8700

Circuit

Z3X-BOX.COM

LG Electronics Inc.

- 56 -

CX8700

rd A

d

,

A

)

4.1.2.5 Checking Rx I/Q data

Test Point

U105 Pin7 (RX0_QM Pin8 (RX0_QP) Pin9 (RX0_IM) Pin10 (RX0_IP)

Check Pin7 (RX0_QM) Pin8 (RX0_QP) Pin9 (RX0_IM) Pin10 (RX0_IP)

Check if there is

ny Major Difference

◆ Refer to Graph 4.1.2(h,i)

Check Pin7 (RX0_QM) Pin8 (RX0_QP) Pin9 (RX0_IM) Pin10 (RX0_IP)

Check if there is

ny Major Difference

◆ Refer to Graph 4.1.2(h,i)

Z3X-BOX.COM

Checking Flow

Similar?

Yes

Re-download the

Software & Calibrate

Similar?

Yes

ll PCS RX check is complete if the phone still does not work change the board.

No

Replace U105

No

Replace Boa

LG Electronics Inc.

- 57 -

CX8700

)

Waveform

RX0_IP

RX0_IM

Graph 4.1.2(h)

RX0_QP

RX0_QM

Graph 4.1.2(i

Circuit

Z3X-BOX.COM

LG Electronics Inc.

- 58 -

CX8700

W

4.2 TX Part Trouble

4.2.1 DCN TX Trouble

Mobile

DCN

duplexer

Dual

PAM

RF TX SAW

RFT6150

< CX8700 DCN TX Part >

S

Triplexer

Z3X-BOX.COM

LG Electronics Inc.

- 59 -

CX8700

V

Checking Flow

START

9Press “MENU’+”##PROG RAM8700”in Phone idle state.

9Press “MENU’+”##PROG RAM8700”in Phone idle state. 9Press “0000000” & Press “7” FCC Test

9Press “0000000” & Press “7” FCC Test 9Press “2” CDMA FCC

9Press “2” CDMA FCC

-Set CH384 & AGC380

9Spectrum analyzer setting

9Spectrum analyzer setting 9Oscilloscope setting

9Oscilloscope setting

1.Check

PMIC Circuit

2.Check

VCTCXO Circuit

6.Check Duplexer

3.Check RFT6150

3.Check RFT6150 Circuit

Circuit

4.Check RF SAW

7.Check Triplexer

8.Check Mobile switch

Re-download.cal5.Check Dual PAM

Z3X-BOX.COM

CTCXO

LG Electronics Inc.

- 60 -

CX8700

4.2.1.1. Check RFT Circuit

TEST POINT

<RFT6150:+2.9V_TX, +2.6V_MSMP2>

R102:+2.9V_TX

R109:+2.6V_MSMP

C307:+2.9V_TX

PMIC

Z3X-BOX.COM

< PMIC :+2.9V_TX, +2.6V_MSMP2 >

C318:+2.6V_MSMP2

LG Electronics Inc.

- 61 -

CX8700

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 62 -

CX8700

Checking Flow

U102

START

Check R102

+2.9V_TX ?

Check R109

+2.6V_MSMP2 ?

NO

Check PMIC Circuit

C307: +2.9V_TX

YES

NO

Check PMIC Circuit

C318: +2.6V_MSMP2

YES

RFT Voltage is ok.

See next page

Z3X-BOX.COM

LG Electronics Inc.

- 63 -

CX8700

4.2.1.2. CheckVCTCXO Circuit

Test Point

X101 PIN4

VCTCXO

X101 PIN3

Check X101 PIN 3

Refer to Graph 4.2.12

Check X101 PIN4

Replace X101

Checking Flow

X101

START

Similar ?

+2.9V ? Check U302

YES

NO

YES

VCTCXO Circuit OK.

See next page.

Circuit Diagram

TCXO Waveform

Z3X-BOX.COM

LG Electronics Inc.

- 64 -

CX8700

4.2.1.4. Check RFT Circ uit

TEST Point

TX_QP TX_QM

TX_IP TX_IM

CELL_OUT

PIN21

PIN 27 PIN 28 PIN 29 PIN 30

PIN 1, 2, 3, 4

TCXO

PIN15

U102

TX_ON, SBCK0, SBDT0, SBST0

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 65 -

CX8700

r

S

ee nextpa

ge

Signa

e

&MS

r

Check

Refer to Grap

Check U102 I/Q

Pin27. 28, 29, 30

Refer to Grap

Checking Flow

Sta

t

U102 P

in23

CE

Simila

LL_OUT

h4.2.1.4 (A)

?

NO

Data

h4.2.1.4 (B)

YES

NO

RFT Circuit is OK

Check U201 MSM

Check

U102 P

in15

Refer to Grap

TCXO

Simila

h4.2.1.4(C)

?

NO

Check

TCXOCircuit

C

Check

(TX_ON

heck U102 PWR

(+2.6V_

MSMP2

+2.9V_TX)

OK

U102 P

Signal)

≥

2.5

YES

in1

+2.6V_MSMP2 PIN 32 +2.9V_TX PIN: 6,9,13,14,17,19,20,

NO

Z3X-BOX.COM

22,24,25,31

Check

l

PMIC Circuit

TX_O

N

Lin

M

Check

Refer to Grap

Replace U102

U102 P SBC SBD SBST0

Simila

YES

in2

, 3,4 K0 T0

h4.2.1.4 (D)

?

YES

NO

Check SBI Signal LINE&MSM

LG Electronics Inc.

- 66 -

CX8700

(A)

)

p

)

X

_Q_

Waveform

RX_I_P

RX_I_

N

SBDT

Graph 4.2.1.4

Graph 4.2.1.4(C

Gra

R

RX_Q_

h 4.2.1.4(B

P

N

Z3X-BOX.COM

SBST

SBCK

LG Electronics Inc.

Graph 4.2.1.4(D

- 67 -

CX8700

4.2.1.5. Check DCN RF TXSAW

Test Point Checking Flow

PIN3 RF OUT

START

Check F105 Pin1,3

RF IN/OUT Port

Refer to Graph 4.2.1.5

RF_OUT

F105

PIN1 RF IN

Circuit Diagram Waveform

Similar ?

Relpace U103

YES

NO

RF TX SAW is OK.

RF_IN

Z3X-BOX.COM

LG Electronics Inc.

RF_OUT

- 68 -

CX8700

A

4.2.1.6. Check DCN P

PIN11 RF OUT

Test Point

PIN3 PA_R1

U108

M Circuit

Checking Flow

START

Check U108 Pin 2,11

RF IN/RF OUT

Refer to Graph 4.2.12

YES

PAM Circuit OK.

Similar ?

NO

Check U108 Pin4

NO

≥3.8V ? Check VCC Line

YES

PAM Circuit OK.

See next page.

PIN2 RF IN

PIN1 VREF CELL

Check U108 Pin2

YES

PIN4 VCC

≥2.7V ?

NO

Check U108 Pin3

≤1.8V ?

YES

Replace U108

YES

NO

Check +2.9V_TX Line.

And PA_ON.

Check PA_R1 Signal line

Z3X-BOX.COM

LG Electronics Inc.

- 69 -

CX8700

RF_

p

RF_

Circuit Diagram

Waveform

IN

Z3X-BOX.COM

OUT

Gra

h 4.2.1.6

LG Electronics Inc.

- 70 -

CX8700

r

K

Rep

4.2.1.7. Check DCN Duplexer

Test Point

ANT Port

DP104

Checking Flow

t

Sta

Check DP104 Pin1,6

TX_PORT

ANT_PORT

to Graph4.2.1.8

Refe

Similar?

DP101

TX Port

Circuit Diagram Waveform

laceDP

NO

104

YES

Duplexer is O

ANT_Port

TX_Port

Z3X-BOX.COM

ANT_Port

Graph 4.2.1.8

LG Electronics Inc.

- 71 -

CX8700

4.2.1.8 Chcek Triplexer

Test Point Checking Flow

U104

ANT Port

Cell port

U104

START

Check U104 Pin5,2

Cell port/ANT Port

Refer to Graph 4.2.12

Similar ?

Relpace U104

YES

NO

Triplexer Circuit OK.

See next page.

Circuit Diagram Waveform

ANT_Port

CELL_Port

ANT_Port

Z3X-BOX.COM

LG Electronics Inc.

- 72 -

CX8700

4.2.1.9 Chcek Mobile Switch

Test Point Checking Flow

U103

RF OUT

START

Check U103

Check U103 IN/OUT Port

IN/OUT Port

Refer to Graph 4.2.12

U103

RF IN

Refer to Graph 4.2.12

Similar ?

Relpace U103

YES

NO

Mobile Switch Circuit OK.

See next page.

Circuit Diagram Waveform

RF OUT

RF IN

Z3X-BOX.COM

RF IN

RF OUT

LG Electronics Inc.

Graph 4.2.1.9

- 73 -

CX8700

W

V

4.2.2 PCS TX Trouble

Test Point

PCS duplexer

DUAL PAM

RF SA

Mobile SW

Triplexer

RFT 6150

CTCXO

Z3X-BOX.COM

RFT6150

LG Electronics Inc.

- 74 -

CX8700

√

r

p

r

p

R

Checking Flow

STA

T

Press “MENU” + “##PROGRAM8700 ” in Phone idle state

√

Press “0000000”

√

Press “7” FCC Test

√

Press “1” PCS FCC

-1. Set CH384 & 2. AGC 380

√

Spectrum analyzer setting

1. Check

PMIC(LDO) Circuit

2. Check

VCTCXO Ci

3. Check

RFT6150 Circuit

cuit

HDET

6. Check lexe

Du

7. Check Tri

lexer

Z3X-BOX.COM

LG Electronics Inc.

4. Check F SAW

5 Check

Dual PAM

8. Check

Mobile Switch

Re-download SW, CAL

- 75 -

CX8700

TCXO_

T

4.2.2.1. Check Regulator Circuit

TX_LDO_EN

TEST POINT

+2.9V_TCXO

PUT

OU

<+2.9V_TCXO>

+VPWR

++VPW

U302

EN

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 76 -

CX8700

g

Checking Flow

U302

Check U302 PinC1

+2.9V

YES

PMIC Circuit is OK See

Next Pa

e

NO

Replace U302

Z3X-BOX.COM

LG Electronics Inc.

- 77 -

CX8700

r

TCX

T

4.2.2.2. Check VCTCXO Circuit

Test Point

+2.9V_TCXO Pin 4

X101

Pin 3

O_OU

Checking Flow

Start

Check X101 Pin3

Refe

to Graph 4.2.2.2

Similar?

Check X101 Pin4

+2.9V?

NO

YES

NO

VCTCXO Circuit OK

Check U302

Circuit Diagram

Waveform

Replace X101

Z3X-BOX.COM

LG Electronics Inc.

Graph 4.2.2.2

- 78 -

CX8700

4.2.2.3. Check RFT6150 Circuit

Test Point

TX_QM

TX_QP

TX_IP

TX_IM

PCS_OUT

PIN21

PIN 27 PIN 28 PIN 29 PIN 30

TX_ON, SBCK0, SBDT0, SBST0

U102

PIN 1, 2, 3, 4

PIN15

TCXO

Circuit Diagram

Z3X-BOX.COM

LG Electronics Inc.

- 79 -

CX8700

Signa

e

&MS

r

S

ee nextpa

ge

Refer t

r

Checking Flow

Check

PCSB_OUT

o Graph4.2.2.3 (A)

Check U102 I/Q

Pin27. 28, 29,30

Refer to Grap

Check +2.6V_ +2.9V_TX

Start

U102 P

in21

?

Simila

NO

Data

h4.2.2.3 (B)

Similar? Check U201 MSM

YES

U102

MSMP2

OK?

YES

NO

+2.6V_MSMP PIN 32 +2.9V_TX PIN : 6,9,13,14,17,19,20,22,24,25,31

NO

RFT Circuit is OK

Check

Regula

torCircuit

Check

U102 P

Check

TCXO

Similar?

U102 P

SBC

SBD

SBST0

Refer to Grap

YES

in15

h4.2.2.3(C)

YES

in2

K0

T0

h4.2.2.3 (D)

, 3,4

NO

Check

TCXOCircuit

Check

(TX_ON

U102 P

Signal)

≥

2.5

YES

in1

YES

Simila

?

Replace U102

NO

Check

l

Lin

TX_O

N

M

YES

Check SBI Signal Line&MSM

Z3X-BOX.COM

LG Electronics Inc.

- 80 -

CX8700

)

(A)

)

p

)

X

_Q_

Waveform

Graph 4.2.2.3

Graph 4.2.2.3(C

TX_I_P

TX_I_

N

SBDT

SBCK

T

Graph 4.2.2.3(B

TX_Q_N

P

Z3X-BOX.COM

SBST

SBCK

LG Electronics Inc.

Gra

h 4.2.2.3(D

- 81 -

CX8700

RF_

Rep

r

R

4.2.2.4. Check PCS RF TX SAW

Test Point

F_OUT

F 104

Circuit Diagram Waveform

F_IN

Checking Flow

Start

Check F104 Pin1, 3

RF_IN

RF_OUT

Refe

to Graph4.2.2.4

Similar?

NO

laceF

104

YES

RF TX SAW is OK

F_OUT

F_IN

IN

Z3X-BOX.COM

F_OUT

Graph4.2.2.4

LG Electronics Inc.

- 82 -

CX8700

_

p

r

V

A

_

V

4.2.2.5. Check PCS PAM Circuit

Test Point

CC2

U108

P

R1

RF_IN

RF_OUTPUT

REF_PCS

Checking Flow

Sta

t

Check U108 Pin5, 7

RF_IN / RF_OUT

Refer to Graph4.2.2.5

NO

Similar?

Check U108 Pin 9

≥

3.8V

YES

Check U108 Pin6

YES

PAM Circuit is OK

NO

Check VCC Line

≥

2.70V

YES

Check U108 Pin4

NO

Check +2.9V

And PA

TX Line

ON1

Z3X-BOX.COM

NO

≤

lace U108

Re

1.8V

Check PA

YES

_R1 Signal

LG Electronics Inc.

- 83 -

CX8700

RF_

Circuit Diagram

Waveform

IN

Z3X-BOX.COM

OUT

Graph 4.2.2.5

LG Electronics Inc.

- 84 -

CX8700

r

K

Rep

T

R

T

ANT_POR

T

A

R

T

R

4.2.2.6. Check PCS Duplexer

Test Point

Checking Flow

ANT_PORT

DP101

TX_PORT

Circuit Diagram Waveform

RX_PO

T

t

Sta

Check DP101 Pin1,3

TX_PORT

ANT_PORT

to Graph4.2.2.6

Refe

Similar?

NO

laceDP

101

YES

Duplexer is O

RX_PO

TX_ PORT

X_PO

Z3X-BOX.COM

NT_ PORT

Graph4.2.2.6

LG Electronics Inc.

- 85 -

CX8700

r

R

RF_

R

4.2.2.7. Check Triplexer

Test Point

ANT PORT

U104

Checking Flow

Start

Check U104 Pin7,2

PCS_PORT

ANT_PORT

to Graph4.2.2.7

Refe

Similar?

NO

Replace U104

Triplexer Circuit is OK See next page

F_OUT

Circuit Diagram Waveform

F_IN

Z3X-BOX.COM

IN

F_OUT

Graph4.2.2.7

LG Electronics Inc.

- 86 -

CX8700

r

Rep

RF_

4.2.2.8. Check Mobile Switch

Test Point

RF_OUT

U103

Checking Flow

t

Sta

Check U103 Pin1, 2

RF_IN

RF_OUT

to Graph4.2.2.8

Refe

Similar?

RF_IN

Circuit Diagram Waveform

lac

e U

NO

103

YES

Mobile Switch is OK

IN

OUT

RF IN

Z3X-BOX.COM

RF OUT

Graph 4.2.2.8

LG Electronics Inc.

- 87 -

4.3 Logic Part Trouble

4.3.1 Power

4.3.1.1 Power-On Trouble

Circuit Diagram

Test Point

+2.85V_SD

+3.2V_MOTO R

+1.5V_CAMD

Z3X-BOX.COM

+2.8V_LCD

+2.6V_MSMP2

+2.9V_TX

+2.8V_BT

+2.9V_TCXO

+2.6V_MSMA

Checking Flow

START

YES

Check Battery Voltage

> 3.3V ?

YES

Push power-on key and check

the level change of

U302 PWR_ON

YES

Check the voltage

Level of the following port at 302

+1.4V_MSMC +2.6V_MSMP2 +1.8V_MSMP1

+2.6V_MSMA

+2.8V_TCXO

+2.9V_RX

YES

NO

Charge of Change Battery and try again

Check the contact of power-key

or dome switch

Replace the U302

The logic level at

PS_HOLD(C3102)

of U302 = High ?

NO

Re-download software & try again

Z3X-BOX.COM

YES

NO

Does it work properly?

YES

The Phone will power on.

The power-on procedure is completed.

NO

The problem may be elsewhere.

Does it work properly?

Replace the main board.

4.3.1.2 Charging Trouble

Circuit Diagram

Test Points

Pin1 CON401

V_BATT

Z3X-BOX.COM

U402

Checking Flow

SETTING : Connect the battery and the charging adaptor (TA) to the phone

START

YES

Voltage at +V_CHAR

of D402 = 4.8V?

YES

Voltage at C309 = 4.8V?

YES

Voltage at +VPWR

of C326 = 4.2V?

YES

The logic level at CHG_MODE

of Q401 = Low?

YES

NO

The charging adaptor (TA) is out of order. Change the charging adaptor.

NO

Replace U402, D403

NO

Replace PMIC [ U302 ]

NO

Replace Q401

Is the battery

charged

Z3X-BOX.COM

YES

Charging will operate properly

1. Check the Battery contact pin [ CON401 ]

NO

2. The battery may have the problem Change the battery and try again.

4.3.2 LCD

4.3.2.1 LCD Trouble Circuit Diagram

• Check point

• LCD Control signals

From MSM : D2[0:15], LCD_RESET/, SLCD_RESET/, MLCD_IF_MODE, LCD_RS, M_VSYNC, MLCD_CS/, SLCD_CS/, OE2/, WE2, LCD_BL_EN, L CD_BL_FC/

- The assembly status of the LCD Module

- The status of Connector connection

- The Soldering of connector

Test Points

C319 : +2.8V_LCD

Z3X-BOX.COM

F410

U302

F407 F408 F405

CON404

F409

F403

F401

Checking Flow

START

Yes

Voltage at +2.8V_LCD

of U302 = 2.8V?

Yes

Check the

Control signal

D2[0:15], RESET/,

LCD_CS/, WE2/,RS

Yes

Check CON404 soldering

Yes

No

Replace U302

; Check F401, F403, F407, F408, F409, F410

No

Re-solder CON404

Change the LCD Module

Z3X-BOX.COM

4.3.3 Camera

4.3.3.1 Camera Trouble

Circuit Diagram

Camera 1.5V Digital

• Camera Control signals

From MSM : CAM_RESET/,CAM_MCLK, CAM_SCL, CAM_SDA, To MSM : CAM_PCLK, CAM_DATA[0:7], CAM_VSYNC, CAM_HSYNC

Z3X-BOX.COM

Test Points

• Check point

- The assembly status of the Camera Module

- The Soldering of connector

X101

C330 : +1.5VCAMD

U302

F410 F405CON404

F402

F406

F409

F404

Z3X-BOX.COM

U101

U105

4.3.4 Audio

4.3.4.1 Speaker Trouble

Circuit Diagram

Test Points

C110 C113

C112

U106

Z3X-BOX.COM

U103

L103

R144

Checking Flow

SETTING : “Melody on” at sounds of test menu.

START

Voltage at L103

Is about 3.4~4.2V

Yes

Check the audio signal at

C112, C113

Yes

Check the audio signal at

C110

Yes

Check the state

Of contact of speaker

NO

Check the Soldering of

R144

Re-solder R144

Check the Soldering of

C112, C113

Re-solder C112, C113

Check the Soldering of

U103

Re-solder U103

Replace Speaker

Yes

NO

Replace U106

Replace MSM

Replace U103

Yes

Z3X-BOX.COM

Speaker will work properly

4.3.4.2 Receiver Trouble

Circuit Diagram

Test Points

R315

U305

C338

R314

Z3X-BOX.COM

Checking Flow

START

Voltage at C338

Is 2.6V

Yes

Check the audio signal at

R314, R315

Yes

Check the audio signal at

R314, R315

Yes

Check the state

Of contact of receiver

NO

Check PMIC

Check the Soldering of

U305

Yes

Re-solder U305

Check the Soldering of

R314, R315

Yes

Re-solder R314, R315

Replace Receiver

NO

Replace MSM

Replace U305

Yes

Receiver will work properly

Z3X-BOX.COM

4.3.4.4 Headset Trouble

Circuit Diagram

CON402

Test Points

R415

R416

R405

Z3X-BOX.COM

C116 C115

LG CX8700, CX8700B, CX8700BWA Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual