E:\维修手册\W97055A3\97055 Service Manual
Contents
1. Check th T ki d Check the contact of ees Ue WOIKITIE CONSENT Ng receiver with PCBA whether 1s normal i whether is well Ok Check those components of receiver circuit whether Solder the bad components Is broken or soldered NG 7 or change them empty Ok a A Check the connectivity NG Check PMU solder it among each signal again or change it Ok v End 2014 03 12 Page 35 of 53 97055 Service Manual Internal 2 4 6 MIC _ Block Diagram of display MCSIASI a I I y I i gt wr ai re BZ I ald Coe 28 E MM FECI I I P7 Analog MIC rus c p j I z I 511 I r RT HI LN VIND pb miw C TAU VE p n I Die 1 a i PPS EN a ad I i I I la hb 198 esta Um es P BI ALLIEN Fr c DAL YNG HI I 00 88 d iL iiaia I w I ne l B i L lan 3 pa I n il a I m sd I L J REX Op FE EN I AL VINO Pei fS X NVN ALI NO RH AP Lan m w m m m _ Circuit Analysis The voice signals are switched by MIC from AU_VINO_P N to PMU and are sent after processed gt Trouble shooting No receiving call may check saw filter which is the component of MIC circuit whether solder well and the voltage of MICBIAS whether normal also may check the circuit of PMU with AU_VINO_P and AU_VINO_N which is the input signal of tone According to2. bad may solder again or change them as PMU MIC 2014 03 12 Page 36 of 53 Repair flow Person who calling to you can t hear your voice MIC no any voice Check the working current 97055 Service Manual Internal whether is normal Ok Check the soldering status between MIC and PCBA whether is well Ok Check the connection among all signals Ok Check the input of MICBIAS whether is high level Check the components of MIC circuit whether solder Ko Check MIC whether solder empty NM Change MIC or solder it again Check PMU change it empty or be broken 2014 03 12 N 2 or solder it again MG Check PMU change it or solder it again Solder these bad No components or change them Page 37 of 53 97055 Service Manual Internal 2 4 7 Earphone _ Block Diagram of display A AA U FU a a ON 4 6 HP_MP3L 1 AY 6 EAR DET i 7 c526 R512 vp ZE uw M i DL Ll h l E hp b I Ii ta G cmm d ca 100nF O paga W AU VN PI E lt HP MIC 16 Qe x amp a ee y I UT 2014 03 12 Page 38 of 53 97055 Service Manual Internal _ Circuit Analysis The earphone circuit are made of 4 signals They are special voltage HP_MIC tone signals HP MP3L_1 HP_MP3R_1 and FM antenna signal FM ANT _ Troub
3. IG RXP n s i RX BBiP AGES RXN i s al Rx BIN ud 2 order fiiez with Jaki mp E I 1 TIA KC Calibration E DCOC san Koi 4 m 18 9 d outer loop Calibration ul ka Pala iGki 34 6 dB dh cbep Hal mE i 18 5 5 i aX BOP GD pag kar K n e E R RX EBON aa TOD BAD RYN m a IL ss vl 3 4 modes 26 TOD SC 3G 5C sled i Ll 136 OC ToD DC 1i 5 11 U i T R 26 LB HXP S z 26 LB HEN OQ P i skd al i BLE detector T IUS l R 3G HB AXP m x 26 HB RXN E 3 ET ME detector T EF H I Tochange LNA as ODO DL t 3 ke m n a vt Comparador Te chany Didar ac CUR LK i To AM digital TT The receiver circuits are all regulated by the internal LDOs The direct conversion LlF receiver contains all active circuits for the complete receiver chain supporting single cell SC dual cell DC 3G WCDMA 3G TDSCDMA and 2G GSM GPRS EDGE GGE mode reception The path contains a total of 7 LNAs Low Noise Amplifier The first 4 LNAs support 3G Band1 2 3 4 5 6 8 9 the fifth LNA supports TDD B40 the last 2 LNAs support GGE low band GSM850 900 and GGE high band DCS1800 PCS1900 GGE high band LNA also supports TDD B33 B34 B39 2014 03 12 Page 21 of 53 Internal 97055 Service Manual ission 2 3 2 RF Transm ission gt Block Diagram of RF Transm IT E E K Rae 1 d i LED gre J 4 s SM
4. Z Si o EOS barrier whether the receive and send channel of send signal peu circuits of RF system Check the suited NO components of send circuit whether is well l Check the suited components of send circuit Ok whether is broken or solder empty No Ok Check the status of RF PA No Solder the bad whether is components or change Check the Balun broken or the broken components soldered empty Ok Ok Ok Check the sending circuit and receiving circuit the receiving circuit may refer Check the status of the sending circuit MT6572 MT6166 whether is broken or solder empty No Solder MT6572 MT6166 XK Ok End again or change it 2014 03 12 Page 24 of 53 97055 Service Manual Internal 2 4 Peripheral Subsystem 2 4 1 Display Block Diagram of display ES UU B ii U d w I 2 I I sat ee kn ee ee aa Les sa ALA EIL eo ga Mu U Td Cala 1 1 wZ B AN ca Fi mad YR prof LCD i ADC PERNT PTh g dp Ll1 AB I En AAN J m m ee m m m m ee ee P Circuit Analysis The display of W97055A3 used 4 0 inch WGA color LCD Its data interface include MIPI port and signal controlled lines The digital port of LCD is driven by BBIC MT6572 The several saw filters are used to Electro Magnetic Interference in the middle cycle and its power supplied by VIO 2 8V of PMIC and its driven circuit of backlight is supplied by the four common anode and backlig
5. cancellation An ARM6 Cortex R4 DSP and 2G and 3G coprocessors provide a powerful modem subsystem capable of supporting WCDMA Category 14 21 Mbps HSDPA downlink and Category 6 5 76 Mbps HSUPA uplink data rates or TD SCDMA Category 14 2 8 Mbps HSDPA downlink Category 6 2 2 Mbps HSUPA as well as Class 12 GPRS and EDGE MT6572 also embodies wireless communication device including WLAN Bluetooth and GPS With four advanced radio technologies integrated into one single chip MT6572 provides the best and most convenient connectivity solution among the industry MT6572 implements advanced and sophisticated radio coexistence algorithms and hardware mechanisms It also supports single antenna sharing among 2 4 GHz antenna for Bluetooth WLAN and 1 575 GHz for GPS 2014 03 12 Page 8 of 53 97055 Service Manual 2 2 Baseband Subsystem Internal 2 2 1 Startup Principle Block Diagram of startup pm an um r n ane BE Maa ota 1K PWRKEYM 15 Ba CU gt AN 4 siy ed p KROWO A A A pa Keg yy LL 2 MH 1 Ay AKIN PBA E IA aD e m Lee eee ee ee ee e e l 2014 03 12 Page 9 of 53 97055 Service Manual Internal gt Circuit Analysis The power on principle of MT6323 implement by MTK software and VBAT voltage diversion to others step power during power on process by PMU VRF28 1 2 85 VTCXO_ 1 T ao 1G VTCXO 18 28 a us 13 26MHz reference clock ADO va 185
6. chip is HIGH the other side of vibrator connect GND the vibrator is working gt Trouble shooting If there is no vibrating then confirm the motor are broken If change the vibrator and assembly it there is no vibrating then confirm the vibrator solder empty please solder again The problem is resolved NO vibrating y e Confirm the vibrator if Solder again or change broken or soldered empty No these PMU and component of Vibrator funtion Ok Y Change the vibrator or solder again End 2014 03 12 Page 33 of 53 97055 Service Manual Internal 2 4 5 Receiver _ Block Diagram of display Receiver FL ase a je La mr n prt pil r m me a a ee ee re e hk F i ei e a a _ Circuit Analysis Simulation audio signal are deal with by MT6323 then output to receiver by passed inductor and capacitor filter 2014 03 12 Page 34 of 53 97055 Service Manual Internal gt Trouble shooting First confirm the receiver well may change it and test Because the receiver type is leaf check the contact between receiver with PCBA weather is well and confirm the contact pin clean and no smudge Finally check the channels of the tone signals AU_HSP and AU_HSN and PMU and according to the bad status to solder again or change PMU Repair flow Person who calling to you can t hear your voice MIC no any voice
7. work normally or contact badly and according to the principle check the status of speaker circuit components and check the status of PMU and its outside components whether solder empty or broken Repair flow No ring tone when power on or play media v Check the working current M Check speaker whether whether normal exist short circuit Ok Check speaker No Change speaker Solder those broken components again or change them Check the components of speaker circuit whether exist short circuit Ok Check the two output signals N Solder PMU again or SPK and SPK of PMU change 1t 4 End D 2014 03 12 Page 41 of 53 97055 Service Manual Internal 2 4 9 SIM Card _ Block Diagram of display r TAD EMM TPS I I TN Manu TP D8MM ER cr 9 U T Ti LLL pomena Z Fi n JARA oe hana 1 V 24 e a I N ud K i SMEFHSMEFTF S512 1B2DF 26A I K cis d E ne ag ery el E Sl 1 B g IE YR SRN SS E NAN Hd p SANA lt _ lt soa EC y Raw o A i Pawi SING PRIU 13 X U u I IVSIM _PMUM 13P a H I Pav gu SOM yy AAA BREST I3 gt SIMIL PMUL 13 MCDA TAR 13 MCTDAT3 3 13 MOTO p13 MH RO a gt IMCICK 313 2 LIA ra di we r r r er m WMCIDATT 113 y _ Circuit Analysis The MT6323 can supply dual SIM card port The 4 signal cables c
8. 100 Analogbaseband moo was 2808 14 Ade VCAMA 1 5 8 2 Analog po camera module vi028 1 2 1 3 1 5 1 8 2 ino 1 211 311 511 8 2 A a Aa VGP1 DLDO VGP2NGP3NG aaa 4 Ta me General purpose LDO1 2 3 6 PANVGPS VGP6 1 2 1 3 1 5 1 8 2 DLDO VEMC 1V8 5 9 8 3 0 33 1 8V EMMC o 12 13 1511 8 2 5 2 8 3 0 3 3 200 Vibrator RICLDO VRIC 18202 128 LE O Description of the Signals in the Circuit Diagram in This Section Signal Name Functional introduction Reference value or waveform chart VBAT Main supply source Range 0 4 2V PWR KEY 1 Power ON OFF signal Range 04 N Range 04 N 4 2V mE nu EBEN S 2014 03 12 2014 03 12 Page 100f 53 10 of 53 97055 Service Manual Internal gt Phone can t power on trouble shooting I PCBA no power on Observe the current change status when the external power supply steadily gives the output to PCBA Also the external power supply can display output voltage and current The external power supply exports about 4 0V voltage 2 0A current check 1 If the current value is about 10mA the clock don t work normally Check the major clock Crystal X600 BBIC U101 Flash U402 and peripheral electronic component whether empty soldering or not conjoint soldering stability of power supply Check the input and output range value of 26MHz clock the aberrance state of wave shape the state of frequency When push power key or plug charger observe
9. 4D Avnnta gps 2014 03 12 Page 48 of 53 97055 Service Manual Internal gt Trouble shooting Turn on the radio function but can t receive radio stations 2 possibilities 1 No sound from headphones First make sure that if the headset and contact with the 3 5 earphone port then check the radio chip voltage is normal final inspections of radio chip MT6627 and peripheral devices for damage or cold solder joint can be replaced or re welding test 2 A rustling sound headphones but the radio listening is not clear First to confirm status of local radio signals such as good and then check the radio antenna radio antenna is connected through a 3 5 earphone port for headphones to signal reception check the antenna connection and exposure pathways final inspections of radio chip MT6627 and peripheral devices for damage or cold solder joint can be replaced or re welding test No FM function No has no voice No Check the FM timbre 19 poor through earphone earphone port Check whether Check whether earphone No om touch well with earphone Re insert empty solder port or not broken or not Ok No Check whether No Change or solder FM_ANT components pm Ean a Mu MT6627 again empty solder or not EIS Dad Components End 2014 03 12 Page 49 of 53 Internal 97055 Service Manual 2413 BT Block Diagram of display wireless FM N n IHI TO IF E E I io B I BEL I P Gd 38 H fF G H 4N H U S E
10. 97055 Service Manual Internal 97055 Service Manual V1 0 Prepared byd Dae 2014 03 12 Page 1 of 53 97055 Service Manual Internal Revision record Revision Revision Section Change Version Cause Number Description 2014 03 12 Page 2 of 53 CONTENTS HTH 3 PRODUCT SPECIFICATIONS a din YR tetas de GR RT a i fep eot IRA COR dd AF 3 1 MAINTENANCE TOOLS nasa GUARANTEE 5 2 PRINCIPLE INSTRUCTION AND TROUBLE SHOOTING 424442222222202000002222022 2000 0000000 7 2 4 SYSTEM MODULE BLOCK DIAGRAM pan KAN KGG DI GAAN Ga epe pen NGA 7 2 BASEBANDESUBSYSTE TTT 9 227 STAD PMI CIO Cs sess cesar i GY E dof dei FU Cro die KOG Fr Fd dod Men 9 2 2 2 Ghatding Management Circuits tana 14 a AA ANA as Sages eco o O OA NWN I Eu HR HO EUR e 16 2 1 REF eceDIion T 20 2S AU a A APELA 22 24 PERIPHERAL SUBSYSTEM ee Rau vbe espe ode bab oe paa diia 25 24 Bic AA 25 242 CAO e A ace Leach eem 28 DOLO PA Dada 31 242 eit PAA 33 DAD ROCES AAA D VER EDU PR DR AAA 34 TT 36 2 4 7 Earphone WAND CR ee e YRR YT Y SR 38 2 4 9 Ring LO dd GN AA AS AA AAA FY UG GE A0 JA 9 SIM Card A ditus ra eva Eee E aa PR AA ANA MU IH DRM E FFA 42 TO HOFCONI ECO HET A4 AAV BT Card Connect or uu IE A6 PE T M p 48 DANG posue ccce E E t EI IU A Md et I UAI E S 50 3S FUNCTIONAL TES AA NANA ANA Vei doe oec AA Aa 52 a NAA 52 9 2 VOICE CALTE TIA iN LU Aa I M dd YO aang UB LLLA eU DADO 53 2014 03 12 Page 3 of 53 97055 Service Manual Internal 97055 Service Man
11. E L CIE L HED 4 MT6166 HCS E a B mum Page 22 of 53 2014 03 12 97055 Service Manual Internal BERF Boundary MAW Hi with up 2 AA d TX HB1 2G HB Ma IX BBOPITX BRON 0008 TX HB2 2G HB pt b i TX HB3 36 HB mt i TX LBA 2G LB di F U i TX LB 2G LB Pos MT6572 B51 DATA 2 8 bo u gi D U X BF D DCD t mmmm L t i pa 14 Se IA DET GND DET TMEAS OI I r TAM 2GHB TX S A 2G Path or 3G Path or Path or TDD Reuse W 36 FDD or TDD Path MT6166 Tx Output Port Mapping Circuit Analysis Transmitter consists of 5 output ports TX LB2 and TX HB1 ports are multi mode ports which can support 2G or 3G depending on application circuits on the phone Typ maximum TX output power is OdBm Overall TX gain dynamic range is 78dB in RF and 8dB in BB The power detection circuits are also included for better power accuracy over power region of PA gain mode change In order to ensure power detection accuracy the PCB trace to DET pin should not be put too close to TX output signal traces 2014 03 12 Page 23 of 53 97055 Service Manual Internal gt Troubleshooting Insert effective SIM card the handset can t found network power on No Clean up Check the connection of antenna feed antenna clean the point with PCBA whether is well antenna feed point Ok If display the signal TEN L pa E E zr Rey barrier please the
12. E Laid q d 2 pr Jan BLOCA Y WB GPS U 1 U i U U U 1 U U i gm DG WIM i U U 1 U U U U U U U Zu GPS_DPx_RFOUT AVDO33 WET Page 50 of 53 2014 03 12 97055 Service Manual Internal _ Circuit Analysis BT signal treatment via 4IN1 IC MT6627 chip _ Trouble shooting Bluetooth dysfunction after power on Can t open functions Bluetooth can t be of bluetooth connected Check the assembling No Assemble the Bluetooth Change MT6627 or status of bluetooth solder it again antenna whether is well enema AB Ok Check the outside No Solder the component components whether exists again or change the soldering empty or broken broken components End 2014 03 12 Page 51 of 53 97055 Service Manual Internal 3 Functional Test 3 1 MMI Test input 66 to enter the MMI test mode 1 Keypad test every key including side key if any key is normal there will display appropriate information in the handset screen 2 Backlight Test the function of trichrome LED whether it is normal 3 CTP Test touch panel function 4 T Flash card Test the T flash card whether it can be identified If you have already inserted the SD card LCD displays the SD Card otherwise LCD display the No SD Card 5 Bluetooth Check Bluetooth 6 SIM card Test the Sim card whether it can be identified 7 Vibrating Test the vibrator whether it can vibrate enter this mode the vi
13. Simulation voltage Digital VCAMA voltage IO voltage Reference value or waveform chart 2 8V 1 8V 2 8V Trouble shooting If can t enter the mode or the camera is blurring screen First check the soldering state of connector XJ6 and confirm there is no short circuit and soldering empty finally confirm whether change the camera or not lf change the camera the problem exist still then please check these signals of working voltage and clock whether correct or not according to the trouble solder again or change BBIC Camera function trouble or screen blurred Check the soldering status of XJ connector Ok After change the camera OK Ok Change the camera Ok End 2014 03 12 Solder XJ6 again Solder again or change these CPU and components of camera display Page 30 of 53 97055 Service Manual Internal 2 4 3 KEYPAD gt Block Diagram of display eee ee ee eee ee ee ee ee em BI an AA Ecc CEREREM LL E n g Lii e Lui Se ae Sr R gum e m m m m m m mim miam Diem nm Um C1301 0 1uF la w mm w e um m m m m e m ma Circuit Analysis KCOL signal is a interrupt signal to BB when the key is pressed and it puts high level at the initialization stage KROW signal is a BB output signal and it puts low level at the initialization stage When a key was pressed the keypad dome shorted the KCOL and KROW signal in other w
14. TXEN MODE BS BS2 _ Standoy 0 0 0 o Ra 0 1 J o o RR 0 313 1 0 iBGPRS 1 0 0 1 HBGPRS_ 1 o 1 1 GSM PA SKY77589 Mode Control Logic were 150 18 ass 99L9LIN IA rat Em rmn B pL H p ANNA pro T FM 1 r LR LX LR Be 1 9 LA LR us n ba u LEZ w n LA A E eom 29 _ AS iii OA T H TT T TIES Ci i PIE A NA 1 GRAN UA m L LE D EL Ki HEIC i MT6166 Applications Diagram 2014 03 12 Page 18 of 53 97055 Service Manual Internal p i i WCDMA Lika MHIL vU d ID SAVO dna TIC EL YMI LM ESL S r mu mu Taur Ca ae ar ua IRL 9 WN am iun WAW m Pe ne m mh MT6166 System Block Diagram MT6166 System Block Diagram 2014 03 12 Page 19 of 53 Internal Hc 97055 Service Manual Block Diagram of RF Reception 2 3 1 RF Reception E 5 E E C i _ d R IR i 0 E Hi if L i LOMB S i n La af mU L I EO 9097 LA TI ATA i GN HS sig JN HSL me LA mia in Rat E I N 481 ymu I NA ID E a r EL ra i di d b i mpg n Y P5 o f r and i DT BULAG E U RP 1 U Page 20 of 53 2014 03 12 97055 Service Manual Internal RX LNA BLK DIET Y Deider LDO1 BX MIX DO T ny TOR Bean Den RX TTG nad RL R3H DIAS to all Ex blacks IB b 12 ir D SDE with 18 6 12 ohm for 36 30H mp HN T che er GH 3682 RXN e d aaa ET my by 12 i k FE
15. anual 2 4 10 VO connector Internal _ Block Diagram of display A AA OD Y Y db o Hy a n KCOLO 3 15 _ Circuit Analysis The software is downloaded to W97240B1 project flash and to work with PC by DP DM signals Trouble shooting if the handset couldn t download or had no USB function whether the IO connector circuit exist short circuit And check the circuit channel between the CPU with the T flash card and change the CPU or solder them again 2014 03 12 Page 44 of 53 97055 Service Manual Internal Repair flow No download or USB no function Check IO connector No Solder again or change it whether empty solder or not Ok Check DP DM signal No Solder the CPU again or change it Ok End 2014 03 12 Page 45 of 53 97055 Service Manual Internal 2 4 11 SD Card Connector _ Block Diagram of display 2 Fu le r a La m i i i el 1757 i i Circuit Analysis The BBIC MT6572 corresponds with T flash card by SPI interface _ Description of the Signals in the Circuit Diagram in This Section Signal Name Functional introduction SD card work voltage gt Trouble shooting After the handset be powered on the T flash card can t be found Please check the structure of T flash card connector J3 weather is normal whether the touch pins clean and elastic whether the components in T flash card circuit exist short circuit whether the working volta
16. brator will Vibrate if it is normal 8 RTC 9 SPK test the capability of SPK whether it is normal 10 Receiver Check voice of RECEIVER and can compare it with the normal handset to confirm its status 11 Headset Check the function of earphone If handset checks there is a earphone in audio jack then screen of handset will appear Headset is in And you can test the function of earphone to confirm earphone and MIC 12 FM Radio Test the function of FM whether it is normal 13 Camera Test the function and capability of camera whether it is normal 14 Battery Test the function of battery whether it is normal 15 WIFI Test the function of WIFI whether it is normal 16 Echo loop Check MIC and receiver if they are normal and in this mode you can hear your echo while you say something forward to MIC 17 LCM Test Test the color of LCD whether it is normal The LCD will display red green blue white and black screen 18 GPS Test the function of GPS whether it is normal 19 Proximity Sensors Test the function of proximity sensor whether it is normal 20 Ambient Light Sensor Test the function of ambient light sensor whether it is normal 21 G Sensor calibration 2014 03 12 Page 52 of 53 97055 Service Manual Internal 3 2 Voice Call Test 1 Insert UIM card to mobile phone press and hold Power key to power on 2 Check whether the signal strength is changed normally in normal network environment 3 Dial a fix
17. e 3G smart phone applications with integrated Bluetooth WILAN and GPS modules The chip integrates a Dual core ARM6 Cortex A7 MPCoreTM operating up to 1 2GHz an ARM6 Cortex R4 MCU and a powerful multi standard video accelerator MT6572 supports various interfaces including parallel serial NAND flash memory and 32 bit LPDDR2 for optimal performance and supports booting from SLC NAND or eMMC to minimize the overall BOM cost In addition an extensive set of interfaces and connectivity peripherals are included to interface to cameras touch screen displays MMC SD cards The application processor a Dual core ARM Cortex A7 MPCoreTM which includes a NEON multimedia processing engine offers processing power necessary to support the latest OpenOS along with its demanding applications such as web browsing email GPS navigation and games All are viewed on a high resolution touch screen display with graphics enhanced by the 2D and 3D graphics acceleration The multi standard video accelerator 2014 03 12 Page 7 of 53 97055 Service Manual Internal and an advanced audio subsystem are also included to provide advanced multimedia applications and services such as streaming audio and video a multitude of decoders and encoders such as H 264 and MPEG 4 Audio supported includes FR HR EFR AMR FR AMR HR and Wide Band AMR vocoders polyphonic ringtones and advanced audio functions such as echo cancellation hands free speakerphone operation and noise
18. ed line number to test the voice guality during a call 4 If the preceding tests are normal end the voice call test Otherwise perform the test again or note down failure symptoms for further analysis and repair 2014 03 12 Page 53 of 53
19. ge is normal And check the circuit channel between the CPU with the T flash card and change the CPU or solder them again 2014 03 12 Page 46 of 53 97055 Service Manual Repair flow Can t identify T flash card Check the working current No whether is normal Ok Check the touch pins of No T flash card whether have elastic or solder empty Ok Check the each channel of No signals Ok Check the working voltage No VIO of the T flash whether is normal Ok Check the outside components of T flash connector J3 whether solder empty or broken Ok End 2014 03 12 Internal Check the correlative working components whether have shout circuit Change or solder again the T flash card connector J3 Search the trouble shooting list of CPU Check SPU whether solder empty or broken Search the trouble shooting list of SIM connector Page 47 of 53 97055 Service Manual Internal 2 4 12 FM _ Block Diagram of display ai a a a n NE MORE Pb ia p 2 22 2 2 2 2 utt dim nn m e t n tt t umma wmm mesom deae irat ii Si E RC a VW msma CA CC CEKckc aa FM LANT N BLR LT MN ST m ER Gau i EN ANTI FU IANT Pi UHR a FM LANT P I I WT aan I IL o I i zi 2n d 2 GPS RFN I I ul V Malavnnaa co
20. ht cycles of MT6323 gt Description of the Signals in the Circuit Diagram in This Section Signal Name Functional introduction Reference value or waveform chart LCM BL anode voltage 0 4 2V 2014 03 12 Page 25 of 53 97055 Service Manual Internal gt Troubleshooting The reasons of LCD display abnormal are the following status a EMI SAW soldering empty or soldering connected b LCD assembly soldering empty or soldering connected 1 Display screen white screen blurred and blank First check whether the software is exact or not check the soldering status of LCD LCD FPC pin no excrescent tin no phenomenon of short circuit no smudge and so on Finally check the component of CPU and EMI whether occur soldering empty may solder again these correlative components or change them 2 Display screen dark no backlight First check LCD and its soldering check the working voltage of LCD backlight check the pins of LCD FPC and clear them Finally check the circuit between output port of CPU backlight with LCD and check the working status of outside components If these components are broken then change them 2014 03 12 Page 26 of 53 97055 Service Manual Internal Repair flow LCD display screen dark screen blurred screen blank y check the soldering status Solder EMI component N l of EMI component again Ok Ok Check the soldering status be
21. le shooting Headset failure mainly means no function after being plugged which unrecognizable The headset plug detect signals head enormous MIC if you can identify an earphone but to have a breakdown in the words to the headset MIC circuit to view the HP MIC HP MP3L 1 HP MP3R 1 EAR DET and access between the PMU is normal the headset MIC if there is virtual circuit the device may damage Repair flow After insert the earphone there is not display icon Check 3 5 EARPHONE connector whether is broken or soldered empty Check the working current whether is normal Ok Check those components Process the trouble of MIC circuit whether is No change the bad broken or soldered empty components Ok eck the signal of HEAD MIC whether 19 normal Solder PMU again or change 1t 2014 03 12 Page 39 of 53 97055 Service Manual Internal 2 4 8 Ring Tone _ Block Diagram of display d td LLL D AU SPKNY 6 AVA eaa A lt AU SPKN1j6 BEADTO2 SUB PCBA SPK 5 g 8 ft il 0 d AU SPKPM 6 i AU SPKP1 5 BEAD701 mm mm gt Circuit Analysis The ring tone cycle is achieved by AB amplifier that integrated in PMU MT6323 driving speaker 2014 03 12 Page 40 of 53 97055 Service Manual Internal gt Trouble shooting There is no ring tone when the handset play Mp3 or power on first check speaker whether can
22. mpty or No gt solder them again broken Ok y According to the download failed repair Download software again No the handset when it can t download Solder the CPU if the software handset 1s not normal still change the CPU Ok Y x mm 2014 03 12 Page 13 of 53 Internal ircuits m m WESI m 97055 Service Manual 2 2 2 Charging Management C gt Block Diagram of charging E irm E i 5 Y me A E E DLE 5 o E EE 5 R E 5 T lay a Ad TE mE Ti i Lg E d U Ins pas j da A i M 16 Ins ae WW T 2 A bo El aN N PENAS SER us D m 8 l D I Tm lo Liu A Kal Ka K NZ N Paw d mE UF aM B ET i d NSN EF A KO 8 E yA LLLI EE a A gud gt r aer aled oi Ka o a x ra 97055 Service Manual Internal gt Circuit Analysis The MT6323 integrate the charger control circuit When inserting the charging adapter VCDT detect high level and start the charging program VDRV output low level then drive the MOSFET U311 to charge the battery gt Troubleshooting The main reason of can t charge is I O port connecting failure the detailed reason is I O port empty soldering or connecting soldering and the 5pin I O port of Micro USB connector cable loosen possibly which maybe cause connect bad may change a USB connector cable the detail repair flow in the following chart q Can
23. onnected PMU are the following such as SIMDAT SIMCLK SIMRST VSIM _ Description of the Signals in the Circuit Diagram in This Section Signal Name Functional introduction Reference value or waveform chart VSIM SIM work voltage Trouble shooting If power on can t found SIM card Check every card and their structure confirm every their structure and touch pins are clean And check these components of in line whether short circuit and check whether the working voltage is normal or not Check the circuit between the SIM card with PMU if there is failure you may solder again or change PMU 2014 03 12 Page 42 of 53 97055 Service Manual Repair flow Can t identify SIM card Check the working No current whether normal Ok Check SIM connector each touch pin whether solders empty or has elastic Ok No Check each channel of signal Ok Check J1101 of signal Ok Check VSIM working voltage of No SIM whether they are normal Ok Check the outside components SIM No connector whether exist soldering empty or short circuit Ok End 2014 03 12 Internal Check the correlative components whether short circuit Change or solder again the SIM connector Change or solder again the SIM connector Change or solder again the J1101 Check PMU whether be broken or soldered empty Check SIM connector according to that it processes the trouble Page 43 of 53 97055 Service M
24. ords the KCOL signal is pulled down by KROW signal then give BB a interrupt signal completed the keypad pressed function 2014 03 12 Page 31 of 53 97055 Service Manual Internal gt Trouble shooting 1 Keypad can t use pull any key no response check keys each other whether short circuit 2 Anyone key can t use it normally is dome dirty or golden annular dish dirty clear it OK 3 Any key can t use check these bad keys whether connect the same signal if is the same signal check the BBIC whether soldering empty or PCB open circuit Key functions trouble after power on Y Whether correlative Several keys failed All keys functions failed No components have short circuit or not Y Check these circuits of y keys pin with CPU Check these keys circuit state each other MR Sou ou No whether short circuit or not MD Y Solder CPU again or Ok change it Ok Y Y Check the circuit of every a Solder CPU again or key with CPU change it Clear keys pin and dome Y EN 2014 03 12 Page 32 of 53 97055 Service Manual Internal 2 4 4 Vibrator Block Diagram of display Circuit Analysis Vibrate circuit is composed by reverse diode PMU integrated bypass capacity and the vibrator In the vibrate mode the signal VIB which come from the PMU
25. should check contact state of power key may check the state of FPC keyboard 2014 03 12 Page 11 of 53 97055 Service Manual Internal If the current has obvious variety but no any direction of power on for example keyboard LED shining booting ring and so on then exclude the reason of software causing Download software again if can t resolve the problem then check these main chip whether empty soldering or not BBIC and FLASH may be broken or soldering failure o If the current has several hundred milliampere first check the soldering assembly component for example LCD speaker keyboard link FPC and so on confirm these components whether soldering state well or not Whether there exist short circuit or not If can t resolve the problem please repair in trouble flow of PCBA No power on of plugging in charger If connect charger to handset with battery there is no any response and no any display charging then first check the contact state of battery with SIM connector If no any problem then use a outside power supply to charge handset and observe the state of current If the outside power supply has no current output first please check the soldering state of USB pin with main board then check the working state of power management component finally charge power circuit in the BBIC may be broken need to be changed If Power on handset then it dead or power off automatically First check the outside po
26. t charge hange the better USB charger cable ave SV input in charging I port N gt Solder I O port again ether the soldering state of component or not N gt Solder U3 again Solder PMIC again Y Y 1 The End b 4 PCB broken 3 2014 03 12 Page 15 of 53 Internal e r 97055 Service Manual 2 3 RF Subsystem Block Diagram of display ik E E EB E I E Be u EI ia ET El E 5 Ua of i 8 as MR WD WU yE T T Yin hg gleb BAR 4 eO po HYT aT m Erim im n mwyn k ams Bi E E d ik id rp mi L e I il Hi cs FE PEN f lk I JN y pot PEU d A PISI 0 as 86 mne asco NE E posco pr Page 16 of 53 2014 03 12 97055 Service Manual Internal Circuit Analysis This circuit shows the transmitter and receiver path of GSM GPRS EDGE WCDMA The RF signal which is amplified by RF PA transmits to antenna through antenna swith and than transmits to the air R3 R4 C626 C627 make up of the antenna matching circuit When receiver the antenna receiver the RF signal and then demodulated by MT6616 after band filter RFIN_HB MODE VRAMP 4 TX_EN BS1 BS2 Controller Antenna RFIN LB RX2 GSM PA AP6682 Functional Block Diagram 2014 03 12 Page 17 of 53 97055 Service Manual Internal MOD
27. the input wave with oscillograph is regular 26MHz sine wave or not and follow output clock wave is regular or not no too anomalous burr 20MHz sine wave If the shape of wave is not regular then adjust the RF circuit also check the state of incidental circuit the working state of component by clock input become normal and steady 2 If the current value is about 20mA then the software may have some problem need download software to test If the current keep in the value about 50mA or over 80mA then the BBIC may be broken or soldering failure 3 If the current value is about several hundred milliampere the over current protection will be opened please check these components of connecting VBAT with multimeter check the VBAT to ground and VCHARGE to ground whether there is short circuit or not If there is short circuit first check those associated components of ESD protection circuit second analyses those associated components of VBAT network whether there is short circuit or some components are broken or not The analyzing rule is from easiness to difficulty so resolve these problems that can be analyed easily II Handset can t power on analysis 1 power key can t power on First take out battery use outside DC power supply to charge the handset and pull power key according to variety state of handset current and analyses the reason If the current has no any variety then power key may be failure
28. tween LCD with PCBA Change LCD or solder again Check the soldering status of LCD FPC No Solder LCD FPC again Ok Solder again or change Check the connectivity of these CPU and No all signals components of LCD display Ok Vv Check the VDDIO that is voltage of LCD No 3 Solder or change CPU 2014 03 12 Page 27 of 53 97055 Service Manual Internal 2 4 2 Camera Block Diagram of display m c pP e eS eS ny AVDO SHE p o m m m e m m F7 I a p v v mm mm wn mm m om a gm om e m m m Ty m m m m d momo m mm Tn d ee 2014 03 12 Page 28 of 53 97055 Service Manual Internal Y DDR pica C pt C PAR pai DEET pig PF seri an Tapar ZE pl pas DER Er pt EA S ada dh EEEL I T IH A8 T T i ni U B BIT i mid EE Bas raat ni i ni s E ea m Cua LL RO Saas NIT I mal i al she iB Fog a RS Oe oe A 4X A E Ve cel su Es QE I E d n TEC EU at ow DANT Zala fi I E gt NN LL 2014 03 12 Page 29 of 53 97055 Service Manual Internal gt Circuit Analysis MT6572 communicates with camera mode chip by 8 bit data signals and 2 synchro signals gt Description of the Signals in the Circuit Diagram in This Section Signal Name Functional introduction VCAMA VCAMD
29. ual Internal Product Specifications aaae oO 126 0 65 10mm Battery Standby time About 150 hours depending on network 1350 mAh conditions Li ion Talk time About 10 hours depending on network conditions LCD type WVGA Screen A Micro USB port interface Data cable Interface Micro USB port S Micro SD card E Micro SD card interface interface Headset jack 3 5 mm in diameter 2014 03 12 Page 4 of 53 97055 Service Manual Internal 1 Maintenance Tools Name Constant temperature Hot Air Gun Purpose Heat component Name Constant temperature Hot Air Gun Purpose Heat component Name Soldering Iron Purpose Repair soldering Name DC Power Supply Purpose Supply voltage and current Name Soldering Station Purpose Fix main board Name Pb free Solder Wire Purpose Join component Name Digital Multimeter Purpose Service measure 2014 03 12 Page 5 of 53 2014 03 12 97055 Service Manual Internal Name Oscilloscope Purpose Service measure Name Tool kit Purpose Assemble and Disassemble tool Name Electronic Screw Driver Purpose Assemble and Disassemble tool Page 6 of 53 97055 Service Manual Internal 2 Principle Instruction and Trouble shooting 2 1 System Module Block Diagram Ea EDGE RF WCDMA RF TDSCDMA RF Camera MT6572 is a highly integrated baseband platform incorporating both modem and application processing subsystems to enabl
30. wer supply whether be restricted current or not adjust to equal position and test again If use one enough strength battery to power on then check the content of battery is enough or not If the battery is normal then handset can power on over 3 7V and work stably Also handset will become dead when it power on to play tone may the soldering point of speaker become a short circuit with ground in the board Also LCD MIC etceteras outside components bad soldering will cause dead or power off automatically According to the bad components check it one by one If can t found the fault then analyses 2014 03 12 Page 12 of 53 97055 Service Manual Internal Power on failed and use outside power supply to supply PCBA and observe the change of current If the value of current is on Ifthe value of current is on The current is normal and the high side about the low T 10mA its value 1s about 20mA I Check the signal of Check all of components 26MHz Maia clock crystal which are correlative with whether 1s normal VBAT and change those broken components No y Check some voltages for example Change the 26MHz crystal VCORE VIO VM VRF or solder it again same to CPU N Change the CPU Or solder it again Ok Ok Check the CPU whether Change the CPU ot they are soldered e
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