LG G1500 Service Manual

REVISED HISTORY

DATE ISSUE CONTENTS OF CHANGES S/W VERSION

Initial Release

The information in this manual is subject to change without notice and should not be construed as a commitment by LGE Inc. Furthermore, LGE Inc. reserves the right, without notice, to make changes to equipment design as advances in engineering and manufacturing methods warrant.

This manual provides the information necessary to install, program, operate and maintain the

G1500.

-1-

Table Of Contents

1. INTRODUCTION................................…5

1.1 Purpose ............................................….

1.2 Regulatory Information ..........................

1.3 Abbreviations .........................................

2. PERFORMANCE ..............................….9

2.1 H/W Features .....................................…..

2.2 Technical Specification ..........................

3. TECHNICAL BRIEF ............................16

3.1 General Description ......……..…………..

3.2 Receiver .............................................….

3.3 Transmitter Part …..………………………

3.4 13MHz Clock …………………….........….

3.5 Power Supplies for RF Circuits ………….

3.6 Testing Set-up and Checking Signals ..….

3.7 Digital Main Processor ….....................….

3.8 Analog Main Processor ……..................…

3.9 Power Management …….....................….

3.10 Memories ................................................

3.11 Display and Interface ..............................

3.12 Keypad Switches and Scanning ........... .

3.13 Microphone ..................………………..…

3.14 Earpiece …………………………………...

3.15 Headset Jack Interface ……..............….

3.16 Key Back-light Illumination ………..……

3.17 LCD Back-light Illumination ……………..

3.18 Speaker & MIDI IC ……………………….

4. TROUBLESHOOTING .................… 52

4.1 RF Components .............................….

4.2 Rx Trouble ..........................................

4.3 Tx Trouble ..........................................

4.4 Power On Trouble ..........................….

4.5 Charging Trouble ...........................….

4.6 LCD Trouble .......................................

4.7 Receiver Trouble ................................

4.8 Speaker Trouble .................................

4.9 Mic. Trouble ...................................….

4.10 Vibrator Trouble ...............................

4.11 Backlight LED Trouble ......................

4.12 SIM Detect Trouble ..........................

4.13 Earphone Trouble ............................

5. DISASSEMBLY INSTRUCTION ...... 97

5.1 Disassembly .........................................

6. DOWNLOAD AND

CALIBRATION ……………............. 100

6.1 Download ……….............................…..

6.2 Calibration …………........................…..

100

102

7. BLOCK DIAGRAM ........................... 105

-3 -

8. CIRCUIT DIAGRAM ......................... 107

8.1 Main Chipset ………………….............…..

8.2 Memory & MMI …………….........……….

8.3 MIDI ……………………………….......….

8.4 RF Circuit ……..................................…..

107

108

109

110

9. PCB LAYOUT .................................. 111

10. STAND ALONE TEST ................... 113

10.1 What’s the Standalone Test? .....……

10.2 Standalone Test Equipment Setup…

10.3 H/W Test …….............................……

10.4 Tx Stand alone Test Setting …………..

10.5 Rx Stand alone Test Setting …………..

10.6 What’s the Rx Calibration …………….

10.7 What’s the Tx Calibration ……………..

10.8 How to Rx Calibration …………………

10.9 How to Tx Calibration ………………….

10.10 Target powers in dBm for each

power level ……………………………..

113

114

115

116

118

120

121

11. EXPLODED VIEW & REPLACEMENT PART LIST ...…. 127

11.1 Exploded View ...........................……

11.2 Accessory ...............................……..

11.3 Replacement Parts

< Mechanic component > ……………..

Replacement Parts

< Main component > ………………….

127

129

130

132

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1. INTRODUCTION

1.1 Purpose

This manual provides the information necessary to repair, calibration, description and download the features of LG-G1500.

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 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 are resulted 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 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. Therefore, note that unauthorized alternations or repair may affect the regulatory status of the system and may void any remaining warranty.

E. Notice of Radiated Emissions

The LG-G1500 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.

-5 -

1. INTRODUCTION

F. Pictures

The pictures in this manual are for illustrative purposes only; your actual hardware may look slightly different.

G. Interference and Attenuation

The LG-G1500 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.

-6 -

1.3 Abbreviations

For the purposes of this manual, following abbreviations apply:

Automatic Power ControlAPC

BasebandBB

Bit Error RateBER

Constant Current – Constant VoltageCC-CV

Digital to Analog ConverterDAC

Digital Communication SystemDCS

1. INTRODUCTION

dB relative to 1 milli wattdBm

Digital Signal ProcessingDSP

Electrostatic DischargeESD

Flexible Printed Circuit BoardFPCB

Gaussian Minimum Shift KeyingGMSK

General Purpose Interface BusGPIB

Global System for Mobile CommunicationsGSM

International Portable User IdentityIPUI

Intermediate FrequencyIF

Liquid Crystal DisplayLCD

Low Drop OutputLDO

Light Emitting DiodeLED

Offset Phase Locked LoopOPLL

-7 -

1. INTRODUCTION

Power Amplifier ModulePAM

Printed Circuit BoardPCB

Programmable Gain AmplifierPGA

Phase Locked LoopPLL

Public Switched Telephone NetworkPSTN

Radio FrequencyRF

Receiving Loudness RatingRLR

Root Mean SquareRMS

Real Time ClockRTC

Surface Acoustic WaveSAW

Subscriber Identity ModuleSIM

Sending Loudness RatingSLR

Static Random Access MemorySRAM

Pseudo SRAMPSRAM

Side Tone Masking RatingSTMR

Travel AdapterTA

Time Division DuplexTDD

Time Division Multiple AccessTDMA

Universal Asynchronous Receiver/TransmitterUART

Voltage Controlled OscillatorVCO

Voltage Control Temperature Compensated Crystal OscillatorVCTCXO

Wireless Application ProtocolWAP

-8 -

2. PERFORMANCE

2.1 H/W Features

Item Feature Comment

Support Dual band (EGSM/DCS) Bar Type GPRS

Size 105.2 × 45.6 × 21.3 mm (Max)

Weight 80g (Standard battery)

Battery 3.7V > 850mAh Li-Ion (Standard)

Talk Time (PL : 7) 3hours (Min) at 850mAh (Standard)

Standby Time (PL : 9) 200hours (Min) at 850mAh (Standard)

ANT Type Internal Antenna

2. PERFORMANCE

LCD 128 × 64 Dot, B/W

Back Light LED Back Light

Back Light Color Blue Color

Vibrator Yes (Coin Type)

LED Indicator Use LCD Backlight

Buzzer Yes

C-MIC Yes

Receiver Yes

Earphone Jack Yes (3 Pole Type)

SIM Socket Yes (SIM Block Type)→3V only

Volume key Navigation Key

Voice Dialing Yes

I/O Connect 18 Pin (Batt. 3Pole)

Basic ACC’Y

Option Hand/Neck Strap, Data Kit, CLA, CD

Travel Adapter(3hour-Charging Time)Standard Battery (LI-Ion 850mAh)Earphone (include Hook Switch)

-9 -

2. PERFORMANCE

2.2 Technical Specification

Item Description Specification

1 Frequency Band

GSM

TX: 890 + n × 0.2 MHz RX: 935 + n × 0.2 MHz (n=1~124)

EGSM

TX: 890 + (n-1024) × 0.2 MHz RX: 935 + (n-1024) × 0.2 MHz (n=975~1024)

DCS

TX: 1710 + (n-512) × 0.2 MHz RX: 1805 + (n-512) × 0.2 MHz (n=512~885)

2 Phase Error

3 Frequency Error < 0.1 ppm

4 Power Level

RMS < 5 degrees Peak < 20 degrees

GSM, EGSM

Level Power Toler. Level Power Toler.

5 33dBm ±2dB 13 17dBm ± 3dB

6 31dBm ±3dB 14 15dBm ± 3dB

7 29dBm ±3dB 15 13dBm ± 3dB

8 27dBm ±3dB 16 11dBm ± 5dB

9 25dBm ±3dB 17 9dBm ± 5dB

10 23dBm ±3dB 18 7dBm ± 5dB

11 21dBm ±3dB 19 5dBm ± 5dB

12 19dBm ±3dB

DCS

Level Power Toler. Level Power Toler.

0 30dBm ±2dB 8 14dBm ± 3dB

1 28dBm ±3dB 9 12dBm ± 4dB

2 26dBm ±3dB 10 10dBm ± 4dB

3 24dBm ±3dB 11 8dBm ± 4dB

4 22dBm ±3dB 12 6dBm ± 4dB

5 20dBm ±3dB 13 4dBm ± 4dB

6 18dBm ±3dB 14 2dBm ± 5dB

7 16dBm ±3dB 15 0dBm ± 5dB

- 10 -

Item Description Specification

GSM, EGSM

Offset from Carrier (kHz). Max. dBc

100 +0.5

200 -30

250 -33

400 -60

600~ <1,200 -60

1,200~ <1,800 -60

1,800~ <3,000 -63

2. PERFORMANCE

3,000~ <6,000 -65

Output RF Spectrum (due to modulation)

DCS

Offset from Carrier (kHz). Max. dBc

GSM, EGSM

6,000 -71

100 +0.5

200 -30

250 -33

400 -60

600~ <1,200 -60

1,200~ <1,800 -60

1,800~ <3,000 -65

3,000~ <6,000 -65

6,000 -73

Offset from Carrier (kHz). Max. dBm

Output RF Spectrum

(due to switching

transient)

- 11 -

400 -19

600 -21

1,200 -21

1,800 -24

2. PERFORMANCE

Item Description Specification

DCS

Offset from Carrier (kHz). Max. dBm

Output RF Spectrum

7 Spurious Emissions Conduction, Emission Status

8 Bit Error Ratio

(due to switching

transient)

GSM, EGSM

BER (Class II) < 2.439% @-102 dBm

DCS

BER (Class II) < 2.439% @-100 dBm

400 -22

600 -24

1,200 -24

1,800 -27

9 RX Level Report Accuracy ±3 dB

10 SLR 8±3 dB

Frequency (Hz) Max.(dB) Min.(dB)

11 Sending Response

12 RLR 2±3 dB

100 -

200 -

300 -12

1,000 -6

2,000 -6

3,000 -6

3,400 -9

4,000 -

-12

- 12 -

Item Description Specification

Frequency (Hz) Max.(dB) Min.(dB)

2. PERFORMANCE

13 Receiving Response

* Mean that Adopt a straight line in between 300 Hz

and 1,000 Hz to be Max. level in the range.

14 STMR 13±5 dB

15 Stability Margin > 6 dB

dB to ARL (dB) Level Ratio (dB)

100 -

200 -

300 -7

500 -5

1,000 -5

3,000 -5

3,400 -10

4,000

-35

-30

-12

17.5

22.5

-20

16 Distortion

17 Side Tone Distortion Three stage distortion < 10%

19 32.768KHz tolerance ≤ 30 ppm

20 Power Consumption

System frequency (13 MHz) tolerance

≤ 2.5 ppm

Full power < 243mA (GSM,EGSM), < 209mA (DCS)

Standby Normal < 4mA (Max. power)

-10

30.7

33.3

33.7

31.7

25.5

- 13 -

2. PERFORMANCE

Item Description Specification

21 Talk Time

22 Standby Time

23 Ringer Volume

24 Charge Voltage

25 Antenna Display

GSM/Level 7 (Battery Capacity 850mA): Up to 180 Min GSM/Level 12 (Battery Capacity 850mA): Up to 300 Min

Under conditions, Up to 200hours:

1. Brand new and full 850mAh battery

2. Full charge, no receive/send and keep GSM in idle mode.

3. Broadcast set off.

4. Signal strength display set at 3 level above.

5. Backlight of phone set off.

At least 80dB under below conditions:

1. Ringer set as ringer.

2. Test distance set as 50cm

Fast Charge: < 500mA Slow Charge: < 60mA

Antenna Bar Number Power

-85 dBm ~

-90 dBm ~ -86 dBm

-95 dBm ~ -91 dBm

-100 dBm ~ -96 dBm

Battery Bar Number Voltage

26 Battery Indicator

3.5 ± 0.03V (Call)

27 Low Voltage Warning

3.62 ± 0.03V (Standby)

28 Forced shut down Voltage 3.35 ± 0.03V

1 Li-ion Battery

29 Battery Type

Standard Voltage = 3.7 V Battery full charge voltage = 4.2 V Capacity: 850mAh

-105 dBm ~ -101 dBm

~ -105 dBm

~ 3.62 V

3.62 ~ 3.73 V

3.73 ~ 3.82 V

3.82 V ~

- 14 -

Item Description Specification

Switching-mode charger

27 Travel Charger

Input: 100 ~ 240 V, 60 Hz Output: 5.2 V, 800 mA

2. PERFORMANCE

- 15 -

3. TECHNICAL BRIEF

3.1 General Description

The RF parts consists of a transmitter part,a receiver part,a synthesizer part,a voltage supply part,a VCTCXO part. And the main RF Chipset CX74017[U441]is a single-chip dual-band transceiver for the extended global system for mobile communication[E-GSM900MHz]/ Digital communication system[DCS1800MHz] voice and data transfer applications. This device integrated a direct conversion receiver architecture, which eliminates the need of Intermediate Frequency, a transmitter based on a modulation loop architecture and fractional-N synthesizer part with built in TXVCO and Local-VCO.

3.2 Receiver

The Receiver part in CX74017 contains all active circuits completely, full receiver chain with the exception of discrete front-end RF SAW filters. The filtered and amplified signal is down converted in the RF-mixer to the baseband output. The receiver path is supported by internal channel filtering. The RF front-end circuit is shown Fig. 3-1.

LMSP54AA-097

DCS : 1805 ~ 1880MHz

GSM : 925 ~ 960MHz

ANT S/W

GSMSEL DCSSEL

PCS : 1805 ~ 1880MHz

FAR-G6CS-1G8425-L257

4/3

2/3

vco

Figure. 3-1 RF Front-end Circuit

CX74017

RXQP RXQN

RXIP RXIN

Base Band

Block

- 16 -

3. TECHNICAL BRIEF

A. RF Front End

RF front end consists of Antenna Switch(FL407), dual band LNAs integrated in transceiver(U441). The Received RF signals (GSM 925MHz ∼ 960MHz, DCS 1805MHz ∼ 1880MHz) are fed into the antenna or mobile switch. An antenna matching circuit is between the antenna and the mobile switch. The Antenna Switch (FL407) is used to control the Rx and TX paths. And, the input signals VC1 and VC2 of a FL407 are connected to DCSSEL(GPO_9) and GSMSEL(GPO_11) ports of U105 to switch either TX or RX path on. When the RX path is turned on, the received RF signal then feeds either Rx _900_RF or RX_1800_RF path controlled by GSM-RX and DCS-RX respectively. This Rx_900_RF path contains one SAW filter, followed after the Antenna Switch (FL407), to filter any unwanted signal apart from the DCS RX band. And, the RX_1800_RF path is the same case. The logic and current for Antenna Switch is given below Table 3-1

Table 3-1 The logic and current

CurrentVC2VC1

10.0 mA max2.7 V0 VGSM TX

10.0 mA max0 V2.7 VDCS TX

<0.1 mA0 V0 VGSM/DCS RX

These two paths are then connected to the LNAGSMN (#11) and LNADCSIN (#13) of CX74017 (U

441), respectively. A low-noise bipolar RF amplifier, contained within the U441, amplifies the RF signal. The RF signals from the front-end pass to the receiver mixers within the U441 device.

B. Demodulator and baseband processing

In direct conversion receiver there is only one mixer down-converting received RF signal to BB signal directly. The gain down converting mixer is 40dB at high gain mode and 22dB at low gain mode. The Rx gain setting is done in the AGC algorithm. The nominal gain of the receiver is set as a function of the expected signal strength at the antenna input so that a desired level is reached at the Rx I/Q. 7 blocks in the receiver chain have variable gains, LNA, Mixer, LPF1, VGA1, gmC Filter, Auxiliary gain control and VGA2. The gain settings can be adjustable via 3-wire bus control lines. The baseband signals pass via integrated low-pass filters to the baseband A/D converters. The remainder of the channel filtering is performed by the baseband chipset. The demodulator contains switches to maintain the sense of the baseband I/Q outputs with respect to the incoming RF signal on both GSM900 and DCS1800.

- 17 -

3. TECHNICAL BRIEF

C. DC offset compensation

Three correction loops ensure that DC offsets, generated in the CX74017, do not overload the baseband chain at any point. After compensation, the correction voltages are held on capacitors for the duration of the receive slot(s). A rising edge on the RXEN signal, selected via the serial interface, placed the DC compensation circuitry in the track mode.

- 18 -

3. TECHNICAL BRIEF

3.3 Transmitter Part

The Transmitter part contains CX74017 active parts, PAM and Antenna Switch. The CX74017 active part consists of a vector modulator and offset phase-locked loop block(OPLL) including down-converter, phase detector, loop filter and dual band transmit VCO which can operate at either final RF output frequency. The RF GMSK outputs from the transmit VCO are fed directly to the RF power amplifiers.

GSMSEL

ANT

LMSP54AA-097

S/W

GSM : 880 ~ 925MHz

DCS : 1710 ~ 1785MHz

DCSSEL

PAM(RF3110B)

TXRAMP TXPA BANDSEL1

vco

CX74017

Base

DCS

GSM

Band Block

TXVCO

/D1

PFD

/D2

TXIP TXIN

TXQP TXQN

Fig.3-2 Transmitter Block diagram

The peak output power and the profile of the transmitted burst are controlled by means of power control loop. The power control function is integrated, eliminating the need for directional couplers, detector diodes, power control IC and other power control circuitry. This allows the module to be driven directly from the DAC output. The PA outputs from the directional coupler pass to the antenna connector via Antenna Switch.

A. IF Modulator

The baseband converter(BBC) within the GSM chipset generates I and Q baseband signals for the transmit vector modulator. The modulator provides more than 40dBc of carrier and unwanted side-band rejection and produces a GMSK modulated signal. The baseband software is able to cancel out differential DC offsets in the I/Q baseband signals caused by imperfections in the D/A converters. The TX-Modulator implements a quadrature modulator. The IF-frequency input signal is split into two precise orthogonal carriers, which are multiplied by the baseband modulation signal IT/ITX and QT/QTX. It is used as reference signal for the OPLL.

- 19 -

3. TECHNICAL BRIEF

B. OPLL

The offset mixer down converts the feedback Tx RF signal using LO to generate a IF modulating signal. The IF signal goes via external passive bandpass filter to one port of the phase detector. The other side of the phase detector input is LO signal. The phase detector generates an error current proportional to the phase difference between the modulated signal from the offset mixer and the reference signal from the LO. The error current is filtered by a second order low-pass filter to generate an output voltage which depends on the GMSK modulation and the desired channel frequency. This voltage controls the transmit VCO such that the VCO output signal, centered on the correct RF channel, is frequency modulated with the original GMSK data. The OPLL acts as a tracking narrowband band pass filter tuned to the desired channel frequency. This reduces the wideband noise floor of the modulation and up-conversion process and provides significant filtering of spurious products.

C. Synthesizer Part

The CX74017 includes a fully integrated UHF VCO with an on-chip LC tank. A single sigma-delta fractional-N synthesizer can phase lock the local osillator used in both transmit and receive path to a precision frequency reference input. Fractional-N operation offers low phase noise and fast setting times, allowing for multiple slot applications such as GPRS. The generated frequency is given by the following equation.





ref



VCO

where : = Generated VCO frequency

VCO

N = N-divider ratio integer part FN = Fractional setting R = R-divider ratio

VCO

= Reference Frequency





5.3



- 20 -

3. TECHNICAL BRIEF

The counter and mode settings of the synthesizer are also programmed via 3-wire interface.

4/3 2/3

DCS

GSM

CX74017

2V7_VTCXO

GSM

vco

vco = (N+3.5+FN/2^22)fref/R

Fractional-N

PLL

ref

13MHz

Figure 3-3. Synthesizer Block diagram.

13MHz

AFC

REFCLK

Base Band

Block

D. Power Amplifier Module

The RF3110B[U416] is a Dual band amplifier for E-GSM(880 to 915MHz) and DCS1800(1710 to 1785MHz). The efficiency of module is the 50% at nominal output power for E-GSM and the 45% for DCS

1800. This module should be operated under the GSM burst pulse. To avoid permanent degradation, CW operation should not be applied. To avoid the oscillation at no input power, before the input is cut off, the control voltage Vapc should be control to less than 0.5V. We have to improve thermal resistance, the through holes should be layouted as many as possible on PCB under the module. And to get good stability, all the GND terminals should be soldered to ground plane of PCB.

- 21 -

3. TECHNICAL BRIEF

3.4 13 MHz Clock

The 13 MHz clock (VC-TCXO-208C) consists of a TCXO (Temperature Compensated Crystal Oscillator) which oscillates at a frequency of 13 MHz. It is used within the CX74017 RF Main Chip, BB Analog chip-set (AD6521), and Digital (AD6522).

FREF

Figure 3-4. VCTCXO Circuit.

3.5 Power Supplies for RF Circuits

There are two regulators used in the phone to provide RF power. One is contained inside of ADP3408 (U101), power management IC to provide the power for the VCTXO (X401). The other is used to

provide the power for remaining RF circuits.

Enable SignalPowersVoltageRegulator

VCTCXO2.7V± 0.5VRegulator 1(U101,2V7_VTCXO)

VSYNTHENRF circuitry2.85V± 0.5VRegulator 2 (U414,RF2V8)

Figure 3-5. Regulator Circuit.

- 22 -

3. TECHNICAL BRIEF

3.6 Testing Set-up and Checking Signals

A. Received RF Level and Checks

This section shows the typical RF power levels expected throughout the receiver path. A block diagram shows the locations of the RF measurement points and levels as shown in Fig. 3-11.

Receiver Testing Set-up

To check the receiver the following conditions have to be set:

On a signal generator or a GSM/DCS test box, output amplitude of CW sugnal = -60 dBm at either:

947.4 MHz (CH62) when testing the GSM RX path or 1842.6 MHz (CH699) when testing the DCS RX path. Set the DC power supply to 4.0 V.

Note: All RF values shown are only intended as a guide figure and may differ from readings taken with other test equipment and leads. Lead and connector losses should always be taken into account when performing such RF measurements.

Testing Receiver

Using a suitable high frequency probe measure the RF levels at the relevant points shown in Fig. 3-9 and compare your measurements with those shown in the diagram. If there are any major difference between the readings taken and those indicated then further investigation of that particular point will be required. It will also be necessary to ensure that all the following power supplies and signals are present which control this part of the receiver circuit:

1. The Control Signal of FEM (see Fig. 3-15, 16, 17)

2. RF2V8 (see Fig. 3-12)

3. 2V7_VTCXO (see Fig. 3-13)

4. 13MHz (see Fig. 3-14)

5. CLK, DATA, SEN (see Fig. 3-18)

8. RX IP, IN, QP, QN (see Fig. 3-21)

B. Transmitted RF Power Level and Checks

This section shows the typical RF power levels expected throughout the transmitter path. A block diagram shows the locations of the RF measurement points and levels as shown in Fig. 3-8.

Transmitter Testing Set-up

To check the transmitter the following conditions have to be set:

1. Set the DC Power supply to 4.0 V.

2. Power up the GSM/DCS test set and then establishing a call with an attached mobile on active mode.

3. Select Channel, TX Level and Input Level according to which parameter is required.

- 23 -

3. TECHNICAL BRIEF

Testing Transmitter

Using a suitable high frequency probe measure the RF levels at the relevant points shown in Fig. 3-9,

10. and compare your measurements with those shown in the diagram. If there are any major difference between the readings taken and those indicated then further investigation of that particular point will be required. It will also be necessary to ensure that all the following power supplies and signals are present which control this part of the transmitter circuit:

1. The Control Signal of FEM (see Fig. 3-15, 16, 17)

2. RF2V8 (see Fig. 3-12)

3. 2V7_VTCXO (see Fig. 3-13)

4. 13 MHz (see Fig. 3-14)

5. TXEN, TXRAMP, TXPA (see Fig. 3-19)

6. TX IP, IN, QP, QN (see Fig. 3-20)

- 24 -

RF components (Component Side)

3. TECHNICAL BRIEF

CN303

FL406

U414

FL407

U441 U416

X401

U413

Figure 3-6. RF components (Component Side).

Reference Description Reference Description

U441 RF Main Chipset FL406 Dual SAW Filter

CN303 Mobile S/W X401 VCTCXO

FL407 Ant. S/W U414 LDO

U416 PAM U413 Inverter IC

- 25 -

3. TECHNICAL BRIEF

Test point of Rx Levels

①

③

②

④

Figure 3-7. Test point of Rx Power Levels.

- 26 -

Test point of Tx Power Levels

3. TECHNICAL BRIEF

⑤

⑥

⑨

⑩

Figure 3-8. Test point of Tx Power Levels.

⑦

⑧

- 27 -

3. TECHNICAL BRIEF

Test point of Tx Power Levels

C444

C448

TXRAMP

(R401)

RF2.85V

TXQN TXIN TXQP TXIP

TXPA

(R404)

2V7_VCTCXO 13MHz Clock

RXIN RXQN RXIP RXQP

Figure 3-9. Control signal test points

- 28 -

Control signal test points

TP402(LE)

TP404(Clock)

TP406(Data)

3. TECHNICAL BRIEF

TP403(RXEN)

Figure 3-10. Control signal test points

- 29 -

3. TECHNICAL BRIEF

RXIP

RXIN

CX74017

4/3

Base

Band

Block

AFC

13MHz

2V7_VTCXO

RXQP

RXQN

2/3

REFCLK

TXIP

PLL_LE

PLL_CLK

PLL_DATA

13MHz

I/O

Serial

ref

ref/R

PLL

Fractional-N

vco = (N+3.5+FN/2^22)

vco

TXEN

RXEN

FEENA

PLL_PD

I/O

Serial

BANDSEL2

BANDSEL1

GSM

DCS

TXIN

/D1

10 dBm

TXQP

TXQN

VBAT

VSYNTHEN

/D2

PFD

TXVCO

/SD

OUT Vin

ADP3330_2V85

RF2.85V

TEMPSENSE

RF2.85V

8 dBm

Attanuator

TXEN

6 dBm

8 dBm

-64 dBm

PAM(RF3110B)

TXRAMP

-64.5 dBm

-61 dBm

Dual Saw Filter L257

GSM

925 ~ 960MHz

GSMSEL

TXPA

DCSSEL

ANT

LMSP54AA-097

S/W

DCS

1805~1880MHz

-60 dBm

Figure 3-9. Transmitter & Receiver RF Levels

- 30 -

34 dBm32 dBm

GSM : 880~925MHz

DCS : 1710 ~ 1785MHz

3. TECHNICAL BRIEF

Figure 3-12. Regulator Output (RF2V8)

Figure 3-13. VCTCXO Power Supply (2V7_VTCXO).

- 31 -

+ 106 hidden pages

LG G1500 Service Manual

Specifications and Main Features

Frequently Asked Questions

User Manual