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TCL T728, Service Manual

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TCL T728 Service Manual                                     

 

                  TCL Mobile Communication

 

CO., Ltd

 

第

  1 

页

 

共

  32 

页

 

 

 

 

 

 
 
 

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 

PDF 

文件使用

 "pdfFactory Pro" 

试用版本创建

  

 

 

 

 

 

 

 

 

 

www.fineprint.com.cn

Summary of Contents for T728

Page 1: ...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 Maintenanc...

Page 2: ...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 operati...

Page 3: ...05 17 3 2 CPU MT6205B description 18 3 3 Power ON Control 18 3 4 Charge Circuit 20 3 5 Back light circuit for LCD 20 3 6 Motor circuit 20 3 7 Audio Part 20 3 8 LCD displaying circuit 21 3 9 SIM Card c...

Page 4: ...to this work surface must be covered with an anti electrostatic mat which should be grounded l Grounding Each test equipment should have electrically grounding the third pin provide a safety feature...

Page 5: ...face Never use benzene or any other chemical to clean cellular phone l Confidential The circuitry within this cellular phone contains several components which are regarded as company confidential Only...

Page 6: ...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 hi...

Page 7: ...chematic 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 firs...

Page 8: ...L T728 Service Manual TCL Mobile Communication CO Ltd 8 32 3 Remove the base bottom casing 4 Separate the FPC connector and take out the mainboard from the casing PDF pdfFactory Pro www fineprint com...

Page 9: ...TCL T728 Service Manual TCL Mobile Communication CO Ltd 9 32 PDF pdfFactory Pro www fineprint com cn...

Page 10: ...TCL T728 Service Manual TCL Mobile Communication CO Ltd 10 32 5 Press down the axises 6 Take out the FPC from the base top casing PDF pdfFactory Pro www fineprint com cn...

Page 11: ...TCL T728 Service Manual TCL Mobile Communication CO Ltd 11 32 7 Remove the two screws with a screwdriver PDF pdfFactory Pro www fineprint com cn...

Page 12: ...TCL T728 Service Manual TCL Mobile Communication CO Ltd 12 32 8 Use a plectrum to separate the flip top casing from the flip bottom casing PDF pdfFactory Pro www fineprint com cn...

Page 13: ...TCL T728 Service Manual TCL Mobile Communication CO Ltd 13 32 9 Taking out the speaker and the motor PDF pdfFactory Pro www fineprint com cn...

Page 14: ...28 Service Manual TCL Mobile Communication CO Ltd 14 32 10 taking out the LCM from the flip bottom casing 11 Remove the Motor and the receiver with an Iron around 320 PDF pdfFactory Pro www fineprint...

Page 15: ...TCL T728 Service Manual TCL Mobile Communication CO Ltd 15 32 12 Taking off the FPC for LCM PDF pdfFactory Pro www fineprint com cn...

Page 16: ...8 Service Manual TCL Mobile Communication CO Ltd 16 32 The list 2 2 The process of assembly Basically procedure for assembly is the reverse process of the disassembly PDF pdfFactory Pro www fineprint...

Page 17: ...ay etc if one of the voltage transition modules can t work well then the relative part will have trouble MT6305 Features 1 Handles all GSM Baseband Power Management 2 2 8V to 5 5V Input Range 3 Charge...

Page 18: ...ckage 3 3 Power ON Control 1 Signal voltage for switching on There are two kinds of ways to switch on the handset One way is the high level on In this case the signal from a pressing of on off key tri...

Page 19: ...1 8V Vrtc 1 5V Va 2 8V Vtcxo 2 8V etc These power supply gives power to each parts of electric circuits of a handset at the same time from the MT6305 24th pin the RESET signal restore the system the...

Page 20: ...gram the 4th pin of U400is used to detect the degree of the charging current to avoid the damage of battery while there is a too high current 3 5 Back light circuit for LCD T728 is a bar type phone wi...

Page 21: ...ng 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 SI...

Page 22: ...MT6129 IC Features receiver Very low IF architecture Quad band differential input LNA Quadrature RF mixers Fully integrated channel filter More than 100dB gain More than 110dB control range Image reje...

Page 23: ...ey will be coupled to duplexer U601 at the different time after passing through the antenna E600 type filtering network antenna coupling testing end J600 C620 As the frequency is certain while receivi...

Page 24: ...Input of voice MIC amplification ADC filter Code of voice weave code channel equilibrium GMSK modulate Entering the RF circuit IQ modulate IQ modulator filter Phase and frequency Detect Phase and freq...

Page 25: ...00 and power manager U400 If it is failure to power on this circuit should be checked 3 Maintaining steps At first check if there lack any parts or IC or unreliable contact of ON OFF KEY Then please f...

Page 26: ...CD 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 3...

Page 27: ...abnormal should check the relative circuit parts 3 3If all the voltages mentioned above should check if the control signal from the 1st 3rd 4th 5th of CPU is right If it is still OK try to replace the...

Page 28: ...e if there is a 4 2v at the anode end of the key LED This voltage is supplied directly by battery if it is abnormal please check the power supply circuit part of battery 3 3 The backlight of LCD is em...

Page 29: ...is directly sent to CPU for process At last it is sent to earpiece If there is no transmitting should check this part carefully 3 Maintaining steps 3 1 Using the multimeter to measure the value of th...

Page 30: ...ified 3 2 If this voltage is right should check the filtering circuit related to the ring tone 3 3If this voltage is abnormal check if there has 1 7V at the 1st 7th pin of U201 which comes from CPU If...

Page 31: ...right please check if the D705 can work well with a multimeter The D705 plays a role of protect of the Motor 3 3 If there is no trouble at the above mentioned place check if there is a 4V or so at th...

Page 32: ...rmal please check if the working voltage input signal controlling signal are right If there is no abnormity you can say the U602 cannot work and need to be replaced 5 Due to the signal outputted MT612...

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