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U8185
Maintenance Manual

9 Principles and Failure Analysis

Issue 1.0 (2012-03-23)

Huawei Proprietary and Confidential

If the battery is fully discharged, Vbat < Vweak and the typical voltage is 3.2 V. To protect the
VDD from being pulled down, trickle charging is performed.



Constant current charging

Summary of Contents for U8185

Page 1: ...U8185 Maintenance Manual Issue 1 0 Date 2012 03 23 HUAWEI TECHNOLOGIES CO LTD ...

Page 2: ...he customer All or part of the products services and features described in this document may not be within the purchase scope or the usage scope Unless otherwise specified in the contract all statements information and recommendations in this document are provided AS IS without warranties guarantees or representations of any kind either express or implied The information in this document is subjec...

Page 3: ...ht Huawei Technologies Co Ltd ii About This Document Purpose Prepared by R D Date 2012 03 20 Reviewed by Maintenance support team Date 2012 03 23 Approved by Service representative Date 2012 03 23 Change History Date Version Change Reason Section Description Author 2012 03 20 V1 0 Released the first issue R D ...

Page 4: ...5 4 Components on the PCBA 7 5 Software Upgrade 10 5 1 Upgrade Preparation 10 5 2 Upgrade Procedure 10 5 3 Troubleshooting 11 6 Maintenance Tools 12 7 Disassembly Procedure 14 8 Assembly Procedure 16 9 Principles and Failure Analysis 18 9 1 Block Diagram 18 9 2 Baseband Unit 19 9 2 1 Power on Management Circuits 19 9 2 2 Charging Management Circuits 24 9 2 3 Clock Circuit 31 9 2 4 Memory Circuit 3...

Page 5: ...9 4 2 Keypad 50 9 4 3 Vibration 53 9 4 4 V oice Reception 54 9 4 5 V oice Transmission 58 9 4 6 Headset 60 9 4 7 SIM Card 63 9 4 8 I O Connector 65 9 4 9 microSD Card Connector 66 9 4 10 FM 67 9 4 11 Bluetooth 70 9 4 12 Wi Fi 73 10 Solder Points on the PCB and BGA Chip 75 11 Functional Tests 81 11 1 Keys 81 11 2 MMI Test 82 11 3 Voice Call Test 83 ...

Page 6: ... 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 1 1 Product Introduction 1 1 Appearance Figure 1 1 U8185 1 2 Specifications Category Description Dimensions H x W x D 106 5 mm x 56 mm x 10 9 mm Technical standard WCDMA GSM ...

Page 7: ...69 894 MHz DL GSM 900 MHz 880 915 MHz UL 925 960 MHz DL GSM 1800 MHz 1710 1785 MHz UL 1805 1880 MHz DL GSM 1900 MHz 1850 1910 MHz UL 1930 1990 MHz DL U8185 7 WCDMA 850MHz 824 849 MHz UL 869 894 MHz DL WCDMA2100 MHz 1920 1980 MHz UL 2110 2170 MHz DL GSM 850 MHz 824 849 MHz UL 869 894 MHz DL GSM 900 MHz 880 915 MHz UL 925 960 MHz DL GSM 1800 MHz 1710 1785 MHz UL 1805 1880 MHz DL GSM 1900 MHz 1850 19...

Page 8: ...ower Class 3 GSM GPRS 850 900 MHz 33 dbm Power Class 4 GSM GPRS 1800 1900 MHz 30 dbm Power Class 1 Static sensitivity WCDMA 850 MHz better than 104 7 dBm 3 84 MHz WCDMA 900 MHz better than 103 7 dBm 3 84 MHz WCDMA 1900 MHz better than 104 7 dBm 3 84 MHz WCDMA 2100 MHz better than 106 7 dBm 3 84 MHz GSM 850 900 1800 1900 MHz better than 102 dBm 200 kHz Temperature Operating temperature 10 C to 55 C...

Page 9: ...r service 2 2 Precautions Only qualified technicians are allowed to perform repair and calibration Perform all operations in electrostatic discharge ESD rooms and wear ESD wrist straps throughout the operations Ensure that all the components screws and insulators are properly installed after repair and calibration Ensure that all cables and wires are installed and connected correctly Ensure that t...

Page 10: ...d View Note The components listed in the following table are structural parts of the phone and cannot be used as reference when requesting spare parts Table 3 1 List of components in the exploded view drawing No Description Quantity 1 Touch panel TP 1 2 Front cover assembly 1 3 LCM 1 4 Printed circuit board assembly PCBA 1 5 Rear cover assembly 1 ...

Page 11: ...U8185 Maintenance Manual 3 Exploded View Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 6 No Description Quantity 6 Battery 1 7 Battery cover 1 ...

Page 12: ...se Transmit failure U3202 RF switch Failure of this component can cause Signal receive or transmit failure U3401 RF power module Failure of this component can cause Transmit failure U3501 RF power module Failure of this component can cause Transmit failure U3304 duplexer Failure of this component can cause No signal weak signal registration failure U3901 baseband dual mode RF transception Failure ...

Page 13: ...ip Failure of this component can cause Power on failure software failure J1001 camera connector Failure of this component can cause Photo or video capture failure U6202 RF switch Failure of this component can cause No Wi Fi signal U401 MSM7225A chip Failure of this component can cause Power on failure system halt RF failure U201 PM8029 power chip Failure of this component can cause No power output...

Page 14: ... Accelerometer U1204 39110581 LDO U1301 12070034 Temperature compensated oscillator 19 2 MHz U3101 14240004 RF connector U3201 47140048 RF switch U3202 13010186 SAW filter U3301 47100397 RF power module U3302 13080065 Duplexer U3304 47100387 RF power module U3401 13010189 SAW filter U3402 13080104 Duplexer U3404 47100377 RF power module U3501 13010262 SAW filter U3702 39200333 Terminal dedicated b...

Page 15: ...k vendor_XXX_XXX UPDATE APP Upgrade method microSD card upgrade Normal upgrade Forcible upgrade 5 2 Upgrade Procedure 1 Format the microSD card 2 Create a folder named dload in the root directory of the microSD card 3 Copy the upgrade file to the dload folder 4 Install the microSD card to the phone Power the phone on and enter 2846579 in the idle screen 5 Select SD card upgrade and then touch Conf...

Page 16: ...similar to the normal upgrade While the phone has no battery installed press and hold the V olume and V olume keys and connect the charger to the phone The phone enters the SD forcible upgrade This method is recommended If the forcible upgrade still fails use another microSDcard and try forcible upgrade again 5 3 Troubleshooting Failure Solution The port cannot be found in USB cable upgrade mode C...

Page 17: ...i Technologies Co Ltd 12 6 Maintenance Tools Name constant temperature heat gun Usage to heat components Name constant temperature heat gun Usage to heat components Name soldering iron Usage to maintain and solder components Name DC power supply Usage to supply DC current Name soldering table Usage to secure the PCBA ...

Page 18: ...ry and Confidential Copyright Huawei Technologies Co Ltd 13 Name pb free solder wire Usage to solder components Name digital multimeter Usage to measure during repair Name toolkit Usage to assemble and disassemble components Name electric screwdriver Usage to fasten and remove screws ...

Page 19: ...23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 14 7 Disassembly Procedure 4 Remove the four screws from rear cover 3 Remove the batterycover 2 U8185 before disassembly 1 Wear an ESD wrist strap and ensure that the strap is grounded properly ...

Page 20: ... Copyright Huawei Technologies Co Ltd 15 10 Remove the LCD The phone is then disassembled 9 Open the LCD connector 8 Remove the PCBA from the front cover 7 Use tweezers to release the TP connector Volume key dome and Power key dome 6 Remove the rear cover 5 Release the latches between front and rear covers ...

Page 21: ...td 16 8 Assembly Procedure 4 Install the TP connector Volume key dome and Power key dome and then snap latch between the PCBA and front cover in place 3 Install the PCBA on the front cover Do not cover the TP connector FPC under the PCBA 2 Install the LCD connector 1 Wear an ESD wrist strap and ensure that the strap is grounded properly ...

Page 22: ...2 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 17 8 The phone is now assembled 7 Install the battery cover 6 Install the four screws into the rear cover 5 Install the Power key and Volume key and snap the front and rear covers ...

Page 23: ...uawei Technologies Co Ltd 18 9 Principles and Failure Analysis Before repairing a phone ensure that the failure of the phone is not caused by environmental factors or incorrect functional settings It is recommended that you restore the phone to its factory settings 9 1 Block Diagram Figure 9 1 U8185 block diagram HD1U8185M pdf ...

Page 24: ...CONECTIVITYsignals The baseband chip provides keypad LCD microSD card Wi Fi camera and microphone interfaces The PM8029 provides analog multi channel switch real time clock circuit TCXO clock circuit motor driver circuit and programmable current source The RTR6285Ais the RF signal processing chip responsible for converting uplink downlink RF signals The PCBAcan be divided into four sub systems bas...

Page 25: ...12 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 20 Analysis After the Power key is pressed the phone powers on VHP_PWR main power voltage powers the PM8029 The power management chip then provides the voltages listed in the following table ...

Page 26: ...ng Process Fault symptom power on failure To troubleshoot the power on failure firstly check whether the I Oconnector battery connector is damaged If the I O connector batteryconnector is not damaged use a DC regulated power supply to supply power to the phone and test the phone s current The power on failure may be caused by any of the following conditions No current ...

Page 27: ...ent Is the battery connector J902 normal Replace Q201 N Is Q201 normal Y Re solder or replace U201 Y Weak current End Y Power on failure weak current Re install the phone s software Is the problem solved Is U201 s output voltage normal Replace U201 N N Replace U401 N Does X301 have 32 768 kHz output Replace U601 and re install the phone s software Is the problem solved Y Replace X301 N End Y Y ...

Page 28: ... charger to the phone Power on failure due to excessive current is usually the result of short circuited VBA T circuit Check w hether VPH_PWR and PM outputs are short circuited N Pow er on failure excessive current Test the VBAT circuit Is it a short circuit Is J902 normal Re solder or replace J902 N Y Replace U401 N Is Q202 normal Remove U201 Do short circuits still exist Y Replace Q202 N Replace...

Page 29: ...ance Manual 9 Principles and Failure Analysis Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 24 9 2 2 Charging Management Circuits Figure 9 3 Circuit schematic diagram ...

Page 30: ... shows the internal structure of the PM8029 The PM8029 has three charging states trickle charging constant current charging and constant voltage charging Auniversal charging channel is used VEXT_DC VCHG Q201 pin3 VBAT External PMOS is controlled through BA T_FET_N to implement the charging functions including trickle charging constant current charging constant voltage charging and pulsed charging ...

Page 31: ...rger and battery modes If V VCHG V B the charger voltage is higher than the battery voltage and the pass transistor is enabled The phone is then powered by the charger If V VCHG V B the battery voltage is higher than the charger voltage and the pass transistor is disabled The phone is then powered by the battery To disable the phone to automatically switch to use thecharger power you can configure...

Page 32: ...1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 27 If the battery is fully discharged Vbat Vweak and the typical voltage is 3 2 V To protect the VDD from being pulled down trickle charging is performed Constant current charging ...

Page 33: ... V constant current charging is performed The charging current remains unchanged When VBA T reaches Vmaxsel the charging current decreases and the constant currentcharging is complete Constant voltage charging During constant voltage charging the VDD voltage remains unchanged When Vbat is equal to Vmaxsel and the charging current is lower than the threshold the charging is complete Pulsed charging...

Page 34: ...rging failures The phone does not respond when a charger is connected to it Acharging indicator is displayed after a charger is connected to the phone but the phone cannot be charged To troubleshoot charging failure firstly check whether the batteryconnector is damaged Charging failure Replace the charger N N Is the charger working properly Is USB connector J901 poorly soldered Y Y Re solder J901 ...

Page 35: ... main battery power recovers so that the phone will not shut down None BATT_THERM Battery temperature detection Detects the voltage of the thermistor inside the battery to determine the battery s temperature Cd VREG_S1 Supplies power to the processor core 1 1 V VREG_S2 Supplies power to the MSM application processor 1 1 V VREG_S3 Supplies power to the memory and digital I O 1 8 V VREG_S4 Supplies ...

Page 36: ...erence Measurement or Wave Form VREG_L14 VREG_L15 Supplies power to thecamera VREG_L16 Supplies power to the UIM card VREG_L17 Supplies power to the Bluetooth and Wi Fi modules VREG_L18 Supplies power to the RTR6285A VREG_L19 Supplies power to the AR6005 Wi Fi module 1 8 V 9 2 3 Clock Circuit Circuit Schematic Diagram Figure 9 4 32 768 kHz clock Figure 9 5 19 2 MHz systemclock ...

Page 37: ...oprietary and Confidential Copyright Huawei Technologies Co Ltd 32 Analysis The crystal oscillator generates the 19 2 MHz clock as the system clock and the crystal X301 generates the 32 768 kHz clock as shown in the preceding figure 9 2 4 Memory Circuit Figure 9 6 Circuit schematic diagram ...

Page 38: ...control signal cable Troubleshooting Process Failure symptom The phone cannot be powered on or the power on current is less than 100 mA Solution Upgrade or load the phone s software and check whether the Flash VREG_MSME1 voltage and peripheral components are normal If the problem persists replace the U601 Table 9 2 Circuit diagram signal summary Signal Description Reference Measurement or Wave For...

Page 39: ... level None EBI1_CAS_N DDR column address select valid when at low level None EBI1_CS0_N EBI1_CS1_N DDR chip select signal valid when at low level None EBI1_CKE0 EBI1_CKE1 DDR clock enable signal None EBI1_CLK_P EBI1_CLK_N DDR differential clock None EBI1_DQS0 EBI1_DQS3 DDR data select None EBI1_DQM0 EBI1_DQM3 Input data mask None EBI1_BA0 EBI1_BA1 DDR bank address None EBI1_A0 EBI1_A13 DDR addres...

Page 40: ... Problem solved End Is the antenna in good contact Re install the antenna Are L3202 R3204 L3203 and R3205 soldered properly Re solder or replace them Is U3202 soldered properly Re solder or replace it Are U3202 s power supply and control voltage normal Re solder or replace the U3202 replace C3206 C3207 or R3201 on the power supply network or replace R3210 R3211 or R3212 on the control circuit Trou...

Page 41: ... the power amplifier is connected to the antenna switch The antenna switch transmits signals to the antenna Transmission channel I Q signals from the CPU are amplified by the amplifier in the RF transmitter I Q signals are modulated by Quadrature Upconverter and become RF signals Signals are amplified Signals are output to the attenuation network from the RF transmitter Signals are amplified by th...

Page 42: ...ssue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 37 GSM quad band adopts differentiated reception to match the network Troubleshooting Process Failure No transmission the phonecannot initiate or receive a call Solution ...

Page 43: ...9 soldered properly Re solder or replace them Are R3502 to R3507 soldered properly Re solder or replace them Are L3500 L3504 and C3510 soldered properly Re solder or replace them Are L3501 C3514 and C3513 soldered properly Re solder or replace them Is U3501 soldered properly Re solder or replace it Are U3501 s power supply and control voltage normal Re solder or replace the U3501 replace C3521 C35...

Page 44: ...oblem solved End Is the antenna in good contact Re install the antenna Are C3603 C3608 and L3605 soldered properly Re solder or replace them Are C3607 C3604 and L3604 soldered properly Re solder or replace them Are C3613 C3614 and L3602 soldered properly Re solder or replace them Are C3605 C3606 and L3603 soldered properly Re solder or replace them Send the phone to an advanced service site for re...

Page 45: ...es the receiving and transmitting signals The receiving signals are received from the ANT end of the duplexer and transmitted out from the Rx end the transmitting signals are received from the Tx end and transmitted from the ANT end to the duplexer and then sent out through the antenna The duplexer s Rx and Tx ends are isolated preventing transmission signals from interfering to receiving signals ...

Page 46: ...ved from the antenna After frequency selection and filtering on the duplexer receiving signals are transmitted to the RF receiver Signals are amplified by the LNA Signals are processed by the single ended to differential filter Signals are amplified Signals are modulated by Quadrature Downconverter and become I Q signals After analog to digital conversion ADC signals are transmitted to CPU for pro...

Page 47: ...older or replace it Are L3301 U3302 L3363 and L3307 soldered properly Re solder or replace them Are U3302 s power supply and control signal normal Re solder or replace the U3302 replace C3302 C3301 C3303 or C3315 on the power supply network or replace C3306 C3307 or R3312 on the control circuit Is U3304 soldered properly Re solder or replace it Are L3305 C3316 and C3314 soldered properly Re solder...

Page 48: ... Re install the antenna Is U3304 soldered properly Re solder or replace it Are C3601 L3601 and C3602 R3602 soldered properly Re solder or replace them Are R3701 R3702 C3710 and L3704 soldered properly Re solder or replace them Is U3702 soldered properly Re solder or replace it Are L3705 C3701 and C3702 soldered properly Re solder or replace them Send the phone to an advanced service site for repai...

Page 49: ...ei Technologies Co Ltd 44 Figure 9 10 Transmittingcircuit The main antenna receives and transmits RF signals The duplexer separates the receiving and transmitting signals The receiving signals are received from the ANT end of the duplexer and transmitted out from the Rx end the transmitting signals are received from the Tx end and ...

Page 50: ...enna duplexer RTR6285A s internal LNAand receiver and external single ended to differential filter Reception channel Signals are received from the antenna After frequency selection and filtering on the duplexer receiving signals are transmitted to the RF receiver Signals are amplified by the LNA Signals are processed by the single ended to differential filter Signals are amplified Signals are modu...

Page 51: ... Re solder or replace it Are C3411 L3403 C3403 and C3404 soldered properly Re solder or replace them Are U3401 s power supply and control signal normal Re solder or replace the U3401 replace C3430 or C3431 on the power supply network or replace C3306 C3307 or R3405 on the control circuit Is U3404 soldered properly Re solder or replace it Are L3401 C3419 and C3418 soldered properly Re solder or rep...

Page 52: ...ologies Co Ltd 47 Y Y Y Y N N Y Y N N N N N N Y Y No W900 850 reception Upgrade the software Problem solved End Is the antenna in good contact Re install the antenna Is U3404 soldered properly Re solder or replace it Are C3611 C3612 and L3612 soldered properly Re solder or replace them Send the phone to an advanced service site for repair ...

Page 53: ...ipheral Circuits 9 4 1 Display Figure 9 12 Circuit schematic diagram Analysis The U8185 s LCM uses a 262k TFT LCD 240 x 320 pixels and a serial interface with synchronous clock The MSM7225Aprovides the drive current The LCM is provided by the supplier directly Troubleshooting Process Failure The phone can be powered on but its LCD is blank Solution Check the LCD ...

Page 54: ...roblem Re install the software Problem solved End Is the BTB socket properly soldered Re solder it Replace the LCD Problem solved Follow the soldering specification End End Table 9 3 Circuit diagram signal summary Signal Description Reference Measurement or Wave Form LCDC_RESET_N Reset signal valid when at low level None LCDC_BLUE Blue data bus None LCDC_GREEN Green data bus None LCDC_RED Red data...

Page 55: ...zontal synchronization signal None LCDC_VSYNC Vertical synchronization signal None LCD_ID0 LCD_ID1 LCD_ID0 and LCD_ID1 are LCD s vendor indicators 00 indicates that the LCD is from TRULY 11 indicates that the LCD is from BYD In this case the software can call LCD initiation programs for different LCDs LED LED anode None LED_K1 LED_K2 LED_K3 LED_K4 LED cathode None VREG_L12_2P85 Supplies power to t...

Page 56: ...signal is connected to the control switch of the power management module and triggers the power management module to power on Then the entire system is powered on When the phone is working properly press the Power key the KPD_PWR_ON receives the triggering signal and transmits the signal to the CPU for processing Theworking principle of the Home key is the same as that of the Power key When being ...

Page 57: ...wer key FPC soldered properly Re solder it Is the key damaged Replace the power key FPC Is the power on sequence correct Analyze the software and hardware comprehensively Send the phone to an advanced service site for repair Figure 9 18 Home keyfailure Y Y N N Y Y N N Disassemble the phone Is the spring damaged Home key failure Replace the spring Is the FPC lack of pad Replace the home key FPC Re ...

Page 58: ...one to an advanced service site for repair Circuit Diagram Signal Summary None 9 4 3 Vibration Figure 9 20 Circuit schematic diagram Analysis The vibration motor is powered by VPH_PWR and controlled by PM8029 The PM8029 s VIB_DRV_N pin functions as the drive pin of the motor The motor is installed on a support over the camera BTB socket When the motor is not vibrating VPH_PWR and VIB_DRV_N are bot...

Page 59: ...supply equal to the battery voltage When the motor test starts is the negative electrode of the motor at low level The power supply is normal Further analysis is required Y N Replace the motor Problem solved End Y N Send the phone to an advanced service site for repair Table 9 4 Circuit diagram signalsummary Signal Description Reference Measurement or Wave Form VPH_PWR Main power supply supplying ...

Page 60: ...U8185 Maintenance Manual 9 Principles and Failure Analysis Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 55 ...

Page 61: ...nalysis Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 56 Analysis Figure 9 23 MSM7225A s internal audiostructure Figure 9 24 PM8029 s internal audiostructure The U8185 provides three types of audio output ...

Page 62: ...ed to an 8 ohm load and outputs 500 mW power The speaker is on the rear cover and is in contact with the PCBA through a spring 3 Headset output The U8185 is designed with a stereo headset Troubleshooting Process Failure After a call is established no sound can be heard Figure 9 25 No sound heard during a call Y Y N N N N Y Y Y N N Y Y Y N N No sound is heard after a call is set up Re install the s...

Page 63: ... electret condenser microphone with differential outputs to the MSM7225A s MIC1_P and MIC1_N The name of electret condenser microphone comes from its sound sensing structure similar to a condenser capacitor The following figure shows its schematic diagram Figure 9 27 Schematic diagram of an electretcondenser microphone The bias voltage for the electretcondenser microphone is provided by the MSM722...

Page 64: ... 28 No sound transmitted during acall Y Y N N Y Y N N N N Y Y N N Y Y Y Y N N No sound is transmitted after a call is set up Re install the software Problem solved End End End End Re solder the microphone Problem solved Is the microphone line normal Is the microphone s bias voltage 1 8 V Check U401 Replace the microphone Problem solved Send the phone to an advanced service site for repair Circuit ...

Page 65: ...i Technologies Co Ltd 60 9 4 6 Headset Figure 9 29 Circuit schematic diagram Analysis The U8185 adopts a stereo headset design The headset port is in the IO The headset output uses the amplifier of the PM8029 Troubleshooting Process Failure No sound can be heard from the headset Solution Replace the headset or the headset connector ...

Page 66: ... Is the headset icon displayed Replacethe headset connector Areline components soldered properly End Send the phone to an advanced service site for repair Table 9 5 Circuit diagram signal summary Signal Description Reference Measurement or Wave Form SPKR_OUT_M Speaker s negative electrode SPKT_OUT_P Speaker s positive electrode Speaker wave forms measured over its two electrodes EAR1_M Receiver s ...

Page 67: ...icrophone to function 1 8 V MIC1_P MIC Microphone wave form measured over its two electrodes receiving mono sound MIC1_N MIC MIC2_P Microphone 2 input Connected to the headset microphone MIC2_N Microphone 2 input Headset microphone measured over its two electrodes HPH_OUT_R Output to the headset s right audio channel HPH_OUT_L Output to the headset s left audio channel HS_DETECT_N Headset presence...

Page 68: ...c diagram Analysis The U8185 supports the R_UIM card and connects the R_UIM card through the UIM card slot The PM8029 provides the card slot with VREG_L16_RUIM power of 2 85 V The R_UIM card s reset clock and data signals can be sent to and received from the PM8029 directly Troubleshooting Process Failure The phone cannot detect UIM cards Solution Check whether the UIM card slot functions properly...

Page 69: ...lace cover B and sent it to mechanical design department for analysis Send the phone to an advanced service site for repair Table 9 6 Circuit diagram signal summary Signal Description Reference Measurement or Wave Form VREG_L16_RUIM Supplies power to the UIM card 2 85v UIM1_DATA UIM card data signals UIM1_DATA_ESD ESD protection for UIM card data signals Connected to the ESD protection component D...

Page 70: ...When being connected to the I O connector a charger provides the VCHG charging voltage to charge the battery When the phone is connected to a computer using a USB cable USB_HS_DN and USB_HS_DP are used for communication between the phone and the computer for example upgrading the phone s software or reading information from the phone Troubleshooting Process Failure The phone cannot be charged or d...

Page 71: ...Digital signal 9 4 9 microSD Card Connector Figure 9 32 Circuit schematic diagram Analysis The U8185 supports 8 GB microSD cards The power consumption of 512 MB and 256 MB microSD cards is low while the power consumption for microSD cards of 1 GB or higher is comparatively high which is normal To increase RF capability 33 pF capacitors are added to all data lines Troubleshooting Process Failure Th...

Page 72: ...card not detected microSD card not detected Replace the microSD card Problem solved Y N Remove and then insert the card Is SDCC_DETECT s voltage changed Re installed the software and verify again Y N End Is the microSD card slot soldered properly Send the phone to an advanced service site for repair Y Re solder or replace it N 9 4 10 FM Figure 9 34 Circuit schematic diagram ...

Page 73: ...module are amplified by the MSM7225Aand then sent to the headset or speaker WCN2243 FM section s major features Broad frequency range 76 108 MHz channel interval 50 kHz Transceiver integrated with an FM modem and a frequency synthesizer Complying with RDS and RBDS Manual and automatic tuning Automatic gain control Automatic frequencycontrol Adaptive noise reduction Adjustment free stereo decoder P...

Page 74: ...ency The signals then go through the intermediate frequency filter demodulation module decoding module and are converted to audio output The FM radio uses a headset as the antenna Therefore a headset must be inserted for the FM radio to function Troubleshooting Process Failure The FM radio is malfunctioning Solution If signals can be received but not sound is heard check the headset line No FM sig...

Page 75: ... WCN2243 Bluetooth section s major features Bluetooth baseband processor integrated with 2 4 GHz transceiver Backwardcompatible with BT1 x 2 x EDR and Bluetooth 3 0 Support for GFSK π 4 DQPSK and 8DPSK modulation High capacity high performance ARM7TDMI processor Support for up to seven concurrentwireless connections Support for Class 1 and Class 2 transmission without any additional PA Low power c...

Page 76: ...calibration no additional calibration required The WCN2243 s Bluetooth section has the following modules integrated Bluetooth RF transceiver Bluetooth controller ARM7 and memory Audio I O processing module HCI processing module Sleep control and coexisting I2S interface PCM interface Table 9 8 Circuit diagram signal summary Signal Description Reference Measurement or Wave Form BT_RFIO RF transmiss...

Page 77: ...uetooth active BT_ACTIVE PTA status WLAN_ACTIVE PTA WLAN active SLEEP_CLK External low power consumption clock input and digital 32 768 kHz clock BT_CLK_REQ Bluetooth requests a master reference FM_HRX_IN FM headset RF receiver terminal FM_PRXTX_IO FM primary RF receiver transmitter terminal FM_OUT_R Left audio channel output of the FM radio FM_OUT_L Right audio channel output of the FM radio I2C_...

Page 78: ...Figure 9 36 Circuit schematic diagram Analysis The U8185 uses QUALCOMM s AR6005 chip to realize the Wi Fi function and support 802 11n AR6005 chip s major features Support for IEEE 802 11b g n High throughput Integrated with high efficiency PAand LNAto reduce cost Support for SDIO V2 0 50 MHz 4 bit and 1 bit Low power consumption Support for 19 2 52 MHz reference clock ...

Page 79: ...oubleshooting Process Failure No Wi Fi signals are received Table 9 9 Circuit diagram signalsummary Signal Description Reference Measurement or Wave Form ANTA ANTB ANTC ANTD RF s front end control signal ANTE Shared antenna switch control signal BIAS_REF Internal analog bias reference RF2INN RF2INP 2 4 GHz input RF2OUTN RF2OUTP 2 4 GHz output XPABIAS5 External PA bias voltage GPIO GPIO interface ...

Page 80: ...ip Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 75 10 Solder Points on the PCB and BGA Chip Red R 255 G 0 B 0 V acant point Green R 0 G 255 B 0 Ground point Blue R 0 G 0 B 255 Solder point Magnified views of sections ...

Page 81: ...U8185 Maintenance Manual 10 Solder Points on the PCB and BGA Chip Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 76 Figure 10 1 PM section ...

Page 82: ...e Manual 10 Solder Points on the PCB and BGA Chip Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 77 Figure 10 2 MSM7225A NAND MCP section Figure 10 3 Bluetooth FM section ...

Page 83: ...aintenance Manual 10 Solder Points on the PCB and BGA Chip Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 78 Figure 10 4 Wi Fi section Figure 10 5 RTR8285Asection ...

Page 84: ...U8185 Maintenance Manual 10 Solder Points on the PCB and BGA Chip Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 79 Figure 10 6 Topsurface ...

Page 85: ...U8185 Maintenance Manual 10 Solder Points on the PCB and BGA Chip Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 80 Figure 10 7 Bottom surface ...

Page 86: ...U8185 Maintenance Manual 11 Functional Tests Issue 1 0 2012 03 23 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 81 11 Functional Tests 11 1 Keys Back Search Menu Home key ...

Page 87: ...Press the Volume key to display triple color bars red green and blue 5 LCD backlight test 5 LCD backlight If the LCD backlight repeatedly turns on and off the LCD backlight is normal Press the Volume key to start the next test 6 Camera test 6 Camera Automatically test the camera The phone s camera is turned on and the LCD displays the preview Press the Volume key to start the next test 7 Touchscre...

Page 88: ...es another device with Bluetooth enabled 14 Gravity sensing test 17 Gravity sensor The LCD displays the current acceleration in the X Y and Z axes Place the phone in a position where the angles between the X Y and Z axes are 45 If the acceleration in the X Y and Z axes is equal to each other the phone passes this test 15 Wi Fi test 19 Wi Fi Automatically test the Wi Fi functions If the phone recei...

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