TCL T728 Service Manual
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TCL T728 Service Manual

TCL T728 Service Manual

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TCL T728 Service Manual
TCL Mobile Communication CO., Ltd
T728 Service Manual
(GSM Cellular Phone)
TCL Mobile Communication CO., Ltd, China
July 8, 2005
1st Edition
For Use by Authorized Service/Maintenance Person Only
Documents to Receive This Addendum:
T728 Maintenance/Repair/Operating Manual
第 1 页 共 32 页
PDF 文件使用 "pdfFactory Pro" 试用版本创建
www.fineprint.com.cn

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  • Page 1 TCL T728 Service Manual TCL Mobile Communication CO., Ltd T728 Service Manual (GSM Cellular Phone) TCL Mobile Communication CO., Ltd, China July 8, 2005 1st Edition For Use by Authorized Service/Maintenance Person Only Documents to Receive This Addendum: T728 Maintenance/Repair/Operating Manual 第...
  • Page 2 Preface This is the Electronic Service Manual for the GSM Digital Cellular Telephone from TCL Mobile Communication CO., Ltd. It contains specific information on repair and test procedures. For details on user functions, general operation and installation, please refer to the User Guide.

  • Page 3: Table Of Contents

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd Contents: Precautions for Repair Work ..... 4 ....... 6 Chapter 1 Introduction 1.1 Layout ..........................6 1.2 Introduction.........................6 Chapter 2 Assemble and disassemble ....7 2.1 Schematic process of disassembly ..................7 2.2 The process of assembly ....................16 Chapter 3 Logic Part ......

  • Page 4: Precautions For Repair Work

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd Precautions for Repair Work (Provides general guidelines for undertaking safe and efficient repair work.) ※ Please read the following cautions, notes and warnings before any repair action. AC Power Cord： Don’t short the pins together when you use.
  • Page 5 TCL T728 Service Manual TCL Mobile Communication CO., Ltd The test equipment should be calibrated before used and should be calibration periodical. Cleaning： Before soldering and de-soldering ensure the cellular phone is power off and disconnected from the power source.

  • Page 6: Chapter 1 Introduction

    Chapter 1 Introduction 1.1 Layout 1.2 Introduction T728 uses the solution of Media Tek(MTK)，its baseband part is composed of CPU MT6205 and PMIC MT6305。The RF part is composed of the transceiver MT6129 and the amplifier RF3146。Its a high integrated and valued function-price-ration platform。...

  • Page 7: Chapter 2 Assemble And Disassemble

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd Chapter 2 Assemble and disassemble 2.1 Schematic process of disassembly 1、Remove the two screws from the phone with a screwdriver. 2、Use a plectrum to separate the base top casing from the base bottom casing toward the back direction at first.
  • Page 8 TCL T728 Service Manual TCL Mobile Communication CO., Ltd 3、Remove the base bottom casing 4、Separate the FPC connector and take out the mainboard from the casing: 第 8 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn...
  • Page 9 TCL T728 Service Manual TCL Mobile Communication CO., Ltd 第 9 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn...
  • Page 10 TCL T728 Service Manual TCL Mobile Communication CO., Ltd 5、Press down the axises 6.Take out the FPC from the base top casing: 第 10 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn...
  • Page 11 TCL T728 Service Manual TCL Mobile Communication CO., Ltd 7、Remove the two screws with a screwdriver: 第 11 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn...
  • Page 12 TCL T728 Service Manual TCL Mobile Communication CO., Ltd 8、Use a plectrum to separate the flip top casing from the flip bottom casing 第 12 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn...
  • Page 13 TCL T728 Service Manual TCL Mobile Communication CO., Ltd 9、Taking out the speaker and the motor: 第 13 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn...
  • Page 14 TCL T728 Service Manual TCL Mobile Communication CO., Ltd 10、taking out the LCM from the flip bottom casing: 11、Remove the Motor and the receiver with an Iron (around 320 ℃) 第 14 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建...
  • Page 15 TCL T728 Service Manual TCL Mobile Communication CO., Ltd 12、Taking off the FPC for LCM: 第 15 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn...

  • Page 16: The Process Of Assembly

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd The list. 2.2 The process of assembly Basically, procedure for assembly is the reverse process of the disassembly. 第 16 页 共 32 页 PDF 文件使用 "pdfFactory Pro" 试用版本创建 www.fineprint.com.cn...

  • Page 17: Chapter 3 Logic Part

    Chapter 3 Logic Part 3.1 PM IC MT6305 The series of T728 mobile phones use the power management chip MT6305, which is the energy supply station of the whole mobile phone’s working. It is not only playing the very important role in the circuit of mobile phones, but also it is one of objects to which we need to pay much attention.

  • Page 18: Cpu Mt6205B Description

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd 3.2 CPU MT6205B description General: 1. Dual –core architecture 2. Integrated voice-band and baseband analog front ends 3. 0.18um low-leakage CMOS process, 1.8V core voltage 4. TFBGA 12mm*12mm 0.8mm pitch 181 package 3.3 Power ON Control...
  • Page 19 T728 has a low-level-on system. The signal for switching on a handset is a direct current being to press the on/off key; it should be jumped by high voltage to a low one. (Or is even to jump the high voltage from the low one). Can use a multimeter or oscillograph to form or show this signal.

  • Page 20: Charge Circuit

    3.5 Back light circuit for LCD T728 is a bar type phone with a B/W LCD. The Back light circuit for LCD is simple, and is composed with two LBD, which is under the control of an enable signal LCD-BL from MT6305.

  • Page 21: Lcd Displaying Circuit

    B10 pin ). In the following diagram, the MICBIAS is for offering a bias voltage for Microphone circuit. 3.8 LCD displaying circuit The T728 is a phone with a black and white LCD, which have a simple displaying circuit. The LCD is 128*64 pixel, black and white. 3.9 SIM Card circuit...

  • Page 22: Chapter 4 Rf Part

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd Chapter 4 RF Part RF part is composed by MT6129 and RF3146. The circuits of receiver and transmitter compose the RF circuit. The receiving part mainly completes the filter, the amplification, the demodulation of a signal;...

  • Page 23: Rx Part

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd Fast setting time suitable for multi-slot GPRS application Supporting Multilane： GSM850 Class 4,small MS E-GSM900 Class 4,small MS PCS1800 Class 1 PCS1900 Class 1 GPRS Class 12 3 bus-interfaces General description：...

  • Page 24: Tx Part

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd 4.2 TX Part After the voice signal is weaved and coded in baseband circuit, it forms equilibrium IQ signal before entering U602. In U602, the IQ signal is processed before amplification in U600.The amplifier (U600) is under the control of MT6205.

  • Page 25: Chapter 5 Tools And Faq

    3) The output of all kinds of supplying voltage.4) the right software. Any of the factors having a problem can cause No Power On. The power on circuit of T728 are composed of CPU （U100） and power manager(U400).If it is failure to power on, this circuit should be checked.

  • Page 26: No Display

    1、Trouble：After turning on the phone, there are backlight for key and sound of ring tone, but no display on LCD and no backlight for LCD. 2、Analysis：The T728 phone adopt a 128*64 pixel B/W LCD, which supplied by U400.The control-signal comes from CPU. If the No display problem occurs, should check these parts.

  • Page 27: No Backlight

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd 3．1 Measuring the VDD of the 6 pin of LCD, which 、14 、15 、16 、17 、18 is outputted from the 20th pin of U400.If it is abnormal, should check the relative circuit of these parts.
  • Page 28 TCL T728 Service Manual TCL Mobile Communication CO., Ltd circuit. If the trouble occurs, should check these relative parts, under the control of the signal outputted by U400. 3、 Maintaining steps： 3．1 General speaking, if there is only one Led do not light, there probably has the trouble only with that LED.

  • Page 29: Transmitting

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd Circuit of backlight for LCD 5.5 NO transmitting 1、 Trouble： In normal idle mode, dialing 112, can hear the voice from network, but there is not any sound while scratching the Microphone.

  • Page 30: No Ring Tone

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd 3．3 If it is ok, should measure the value of voltage on the R213、R216.these biases are MICBIASP、 MICBIASN, coming from the B11、 C11 pin of CPU. If these two biases are abnormal, please check the input and output circuit parts of CPU.

  • Page 31: No Net Work

    TCL T728 Service Manual TCL Mobile Communication CO., Ltd 3．1 Let the handset in a vibrating mode ,measure the voltage(VIB, output from the 38 pin of U400) at the cathode of the Motor. If it is abnormal, check the relative parts of circuit of U400.
  • Page 32 TCL T728 Service Manual TCL Mobile Communication CO., Ltd while dialing the emergency call 112. 2、Analysis：The transmitting and receiving circuit composed mainly by U600、U602 and U100. 3、Maintaining steps：testing the channel of transmitting and receiving with a Integrated Tester ,to judge whether the problem is in transmitting part ,or in receiving part；...

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