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U8815
Maintenance Manual

9 Principles and Failure Analysis

Issue 1.0 (2012-02-13)

Huawei Proprietary and Confidential

Figure 9-40

Troubleshooting process for sound failure

Does the

call function normally

after the software

is reloaded?

Is the receiver

volume setting normal?

Is the receiver

connection line normal?

Re-solder the receiver

connection line.

After a call is established,

no sound is heard by the

other party.

Adjust the volume to check

whether the setting is normal.

Does the

handset misjudge

headset insertion?

Check and repair the

headset connector.

End

Is the

receiver volume setting

normal after the receiver is

replaced?

End

Do the

U2002 neighboring

circuits encounter cold joint or

soldering

offset?

End

Return the handset to

the factory for repair.

9.4.4 Call Transmission



Circuit block diagram

Summary of Contents for U8815

Page 1: ...U8815 Maintenance Manual Issue 1 0 Date 2012 02 13 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: ...Technologies Co Ltd ii About This Document Purpose Prepared by R D personnel Date 2012 02 20 Reviewed by Maintenance support team Date 2012 02 23 Approved by Service representative Date 2012 02 23 Change History Date Version Change Reason Section Description Author 2012 02 23 V1 0 Released the first draft R D personnel ...

Page 4: ... Software Upgrade 9 5 1 Upgrade Preparation 9 5 2 Upgrade Process 9 6 Maintenance Tools 11 7 Disassembly Procedure 13 8 Assembly Procedure 17 9 Principles and Failure Analysis 20 9 1 Block Diagram and Handset Introduction 20 9 2 Baseband Unit 21 9 2 1 Power on Management Circuits 21 9 2 2 Charging Management Circuits 26 9 2 3 Clock Circuit 30 9 2 4 Flash Memory Circuit 32 9 3 RF Unit 37 9 3 2 Powe...

Page 5: ...d Confidential Copyright Huawei Technologies Co Ltd iv 9 4 5 Headset 57 9 4 6 SIM Card 59 9 4 7 I O Connector 60 9 4 8 microSD Card Connector 61 9 4 9 FM 63 10 Solder Points on the PCB and BGA Chip 66 11 Performance Test 69 11 1 Keys 69 11 2 MMI Test 70 11 3 Voice Call Test 71 ...

Page 6: ...s for no current 24 Figure 9 4 Troubleshooting process for weak current 25 Figure 9 5 Troubleshooting process for high current 26 Figure 9 6 Charging management circuit diagram 1 27 Figure 9 7 Charging management circuit diagram 2 27 Figure 9 8 Charging management circuit diagram 3 27 Figure 9 9 Charging management circuit diagram 4 28 Figure 9 10 Troubleshooting process for charging failures 29 F...

Page 7: ...ooting process for no LCD display 47 Figure 9 33 Motor circuit diagram 48 Figure 9 34 Vibration maintenance process 49 Figure 9 35 Call reception circuit diagram 1 50 Figure 9 36 Call reception circuit diagram 2 50 Figure 9 37 Call reception circuit diagram 3 50 Figure 9 38 Call reception circuit diagram 4 51 Figure 9 39 7227A audio processing diagram 51 Figure 9 40 Troubleshooting process for sou...

Page 8: ...it diagram 3 64 Figure 9 54 Troubleshooting process for FM radio failure 65 Figure 10 1 Diagram 1 of the solder points on the PCB and BGA chip 66 Figure 10 2 Diagram 2 of the solder points on the PCB and BGA chip 67 Figure 10 3 Diagram 3 of the solder points on the PCB and BGA chip 67 Figure 10 4 Diagram 4 of the solder points on the PCB and BGA chip 68 Figure 11 1 U8815 handset key 69 ...

Page 9: ... the circuit diagram in this section 36 Table 9 5 Logic table of the RF switch 38 Table 9 6 Truths for control signals 42 Table 9 7 Description of the signals in the circuit diagram in this section 43 Table 9 8 Description of the signals in the circuit diagram in this section 47 Table 9 9 Description of the signals in the circuit diagram in this section 49 Table 9 10 Audio output 52 Table 9 11 Des...

Page 10: ...t Introduction 1 1 Appearance Figure 1 1 shows the appearance of the U8815 handset Figure 1 1 Appearance of the U8815 handset 1 2 Features Table 1 1 describes the features of the U8815 handset Table 1 1 Description of the features Item Description Dimensions W x D x H 122 5 mm x 63 mm x 10 5 mm Technical standard Wideband Code Division Multiple Access ...

Page 11: ... in Charger 5 V 1 A Flash 4 GB embedded multimediacard EMMC 4 GB Low Power Double Data Rate LPDDR Camera 5 MP AF Camera Bluetooth BCM4330 supporting BT2 1 and enhanced data rate EDR Wi Fi BCM4330 supporting 802 11b g n Battery Li ion battery 1 350 mA h Display Resolution 800 x 480 pixels Type ThinFilmTransistor TFT Color 16 7 M Size 4 0 inch Connector Charger port Micro USB connector USB port Micr...

Page 12: ... find any mistake or have any suggestion contact Huawei s customer service 2 2 Precautions Maintenance and calibration operations are performed only by qualified technicians All repair and maintenance operations are performed in antistatic rooms with ESD wrist straps correctly worn Ensure that all components nuts and insulators are installed after maintenance or calibration In addition ensure that...

Page 13: ...e 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 lists components in the exploded view Table 3 1 List of components in the exploded view No Description Quantity 1 Touch panel 1 2 Front housing housing A 1 3 Liquid crystal display LCD display 1 4 Steel holder 1 5 Printed circuit board assembly PCBA 1 6...

Page 14: ...nologies Co Ltd 5 No Description Quantity 7 Decorating parts of housing B 2 8 Battery 1 9 Battery cover 1 10 Shielding frame for PA 1 11 Shielding frame for central processing unit CPU 1 12 Main board printed circuit board PCB 1 13 Shielding frame for radio transceiver RTR 1 14 Shielding frame for power management PM 1 ...

Page 15: ...e to the U3101 19 2 MHz crystal oscillators power on failure Failures caused by damage to the U1700 Flash power on failure and software failure Failures caused by damage to the U401 baseband chip and CPU power on failure breakdown and RF failure Failure caused by damage to the U3501 power module GSM transmission failure Failures caused by damage to the U4202RF power module 1850 1910 MHz no signal ...

Page 16: ... Failures caused by damage to the U3901 dual channel RF transmission and receiving RTR6285A no signal weak signal registration failure and GPS failure Failures caused by GPS failure and damage to the J3201 RF connector no signal weak signal and registration failure Failures caused by damage to the J1501 holder connector the battery connector power on and charging failures Failure caused by damage ...

Page 17: ...by damage to the J103 IO connector Micro USB socket charging and data communication failures Failure caused by damage to the MIC101 MIC call transmission failure Figure 4 4 PCBA components diagram 4 Failures caused damage to the J102 RF connector no signal weak signal and registration failure Failures caused by damage to the J107 antenna spring no signal weak signal and registration failure ...

Page 18: ...pack vendor_XXX_XXX UPDATE APP Upgrade method Upgrade using microSD cards Normal upgrade Forcible upgrade 5 2 Upgrade Process 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 handset Power the handset on and enter 2846579 in the idle screen Select SD card upgrade then pres...

Page 19: ...rcibly upgrade the handset 1 Install the battery to the handset if the screen is splashing remove the battery and wait for five seconds before installing the battery again Press Volume and Volume and press the Power key the handset will start SD forcible download The specific download process is similar to the project menu download 2 When the handset has not a battery installed press Volume and Vo...

Page 20: ...ols Table 6 1 lists maintenance tools Table 6 1 List of 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 direct current DC power supply Usage to supply DC current Name soldering table Usage to fix the PCBA ...

Page 21: ...ry and Confidential Copyright Huawei Technologies Co Ltd 12 Name lead free solder wire Usage for soldering Name digital multimeter Usage to measure during maintenance Name toolkit Usage to assemble and disassemble components Name electric screwdriver Usage to fasten and remove screws ...

Page 22: ...t Huawei Technologies Co Ltd 13 7 Disassembly Procedure The following figures show the procedures 1 Ensure that the electro static discharge ESD wrist strap is properly connected to the ground 2 Follow the U8815 disassembly instructions 3 Remove the battery cover 4 Screw off the four screws on the decorating parts ...

Page 23: ...ews on the rear housing after removing the decorating parts 7 Loosen the latch between the front housing and the rear housing by using the housing opener 8 Screw off the three screws on the platelet and loosen the latch between the platelet and the coaxial cable 9 Loosen the latch between the platelet and the front housing with the housing opener and remove the 10 Loosen the camera flash according...

Page 24: ...PCBA 12 Loosen the latch between the On Off key and the steel holder 13 Loosen the latch between the screen and the front housing on the fixing point of the four screws 14 Apply a piece of protective film on the screen 15 Apply a piece of protective film on the touch panel of the front housing 16 Unclench the LCD carefully from the two lower corners of the steel holder of the screen ...

Page 25: ...and the steel holder using the housing opener after LCD is unclenched with a crack left 18 Remove the lead of the motor wire through a soldering iron and remove the motor 19 Remove the receiver 20 The speaker is on the rear housing 21 The flexible printed circuits FPCs of volume Universal Serial BUS USB connection and power on are on the steel holder 22 The disassembly is complete ...

Page 26: ...uawei Technologies Co Ltd 17 8 Assembly Procedure The following figures show the procedures 1 Ensure that the ESD wrist strap is properly connected to the ground 2 Follow the U8815 assembly instructions 3 Install and fix the receiver 4 Pass the LCD connector through the upper part of the steel holder to fix the LCD ...

Page 27: ...holder and the front housing according to the four points 6 Solder the motor lead and fix the motor 7 Install the PCBA adjust the positioning hole of the On key correctly and connect the connector 8 Install the platelet and connect the USB connector 9 Fix according to the positioning hole ring the three screws and connect to the coaxial cable 10 Install the speaker on the rear housing ...

Page 28: ...he rear housing Fix and press it tightly to the latch 12 Screw the four screws tightly on the rear housing 13 Press and fix the decorating parts according to the latch leaving no gap with the front housing 14 Screw the four screws tightly on the decorating parts 15 Install the battery cover Fix and press it tightly to the latch 16 The assembly is complete ...

Page 29: ...o Ltd 20 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 defaults 9 1 Block Diagram and Handset Introduction Figure 9 1 shows the block diagram Figure 9 1 Block diagram ...

Page 30: ...ons U8815 also supports storing phonebook entries and short messages to both the UIM card and the handset Furthermore U8815 supports microSD storage cards In terms of the hardware the handset supports FM radio and recording U8815 supports colored TFT LCD with the resolution of 800 x 480 pixels and provides external ports such as Micro USB charger ports and user identity module UIM card ports In ad...

Page 31: ...815 adopts the independent PM8029 power management chip The power on mechanism is controlled by Qualcomm codes The power on mechanism in the preceding figure is as follows KPD_PWR_ON tests the voltage active low During the power on process the PM8029 power management chip converts the main power supply voltage VHP_PWR to various voltages listed in the following table ...

Page 32: ...ailures are classified into three types no current weak current and high current and many of them are caused by power supply faults If failures of these three types occur rectify them according to the circuit fault troubleshooting methods 1 No current Connect your handset to DC power supply Press the On key The displayed current ranges from 0 to 5 mA 2 Weak current Connect your handset to DC power...

Page 33: ... shows the troubleshooting process for no current Figure 9 3 Troubleshooting process for no current Is the copper foil of the On key is oxygenated No current Clean the On key Does the clock function properly N Y Y N Check the X401 and U3101clocks Y Return the handset to the factory for repair N Power on failure Connect the handset to a fake battery and a maintenance power supply and press On to ch...

Page 34: ...t to a fake battery and a maintenance power supply and press On to check the current Weak current Check U201 Measure and check whether the output frequency of X402 is 32 768 kHz or the output of U3101 is 19 2 MHz Return the handset to the factory for repair Y N Y Power on failure Is the PM output voltage normal Re solder or replace X301 and U3101 N 6 High current Figure 9 5 shows the troubleshooti...

Page 35: ...ct the handset to a fake battery and a maintenance power supply and press On to check the current Large current Return the handset to the factory for repair N Y Y N Power on failure Is the third pin of J1501 grounded Check U201 and J1501 Is the U201 voltage normal Re solder or replace U201 9 2 2 Charging Management Circuits Circuit block diagram The following figures show the charging management c...

Page 36: ...Analysis Issue 1 0 2012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 27 Figure 9 6 Charging management circuit diagram 1 Figure 9 7 Charging management circuit diagram 2 Figure 9 8 Charging management circuit diagram 3 ...

Page 37: ...e USB port The chip is controlled by the I2C The output VPH_PWR supplies power to the power management chip and the battery This chip supports three modes charging mode boost mode and high resistance mode The charging mode is normal charging process The boost mode is USB OTG mode The high resistance mode is power saving mode standby mode without charging Troubleshooting Process There are two types...

Page 38: ...eing connected to a charger the handset cannot be charged End Y N N N Y N Solder J103 Y N Replace U1001 Replace the charger Does pin 3 of Q201 provide output Y N Replace Q201 Is the J1501 battery connector damaged Y Y Replace the J1501 battery connector Is the battery damaged N Y Replace the battery Is the output voltage VPH_PWR available on the U1001 charging chip Does the J103 USB connector need...

Page 39: ...DC The control signal of the charging chip None I2C_SDA_DCDC The control signal of the charging chip None VPH_PWR Main power supply supplying power to the power unit of the main chip Voltage range 0 4 2 V BAT_FET_N The control signal of the metal oxide semiconductor MOS Q201 VBAT Battery voltage Battery voltage range 0 4 2 V USB_HS_DP Positive electrode input of USB differential data bus None USB_...

Page 40: ...igure 9 12 19 2 MHz circuit block diagram 2 Figure 9 13 32 768 kHz circuit block diagram 1 Analysis Figure 9 14 shows the analysis of clock circuit Figure 9 14 Analysis of clock circuit 19 2 MHz clock input is connected to PM8029 and RTR6285A as shown in the preceding figure The TPK_LO_ADJ controls the precision of clock output It includes two stage filter ...

Page 41: ...frequency is stable on crystal oscillators X301 and U3101 Solution Replace X301 or U3101 If the problem persists replace PM8029 Table 9 3 describes the signals in the circuit diagram in this section Table 9 3 Description of the signals in the circuit diagram in this section Signal Description Reference Measurement or Wave Form XTAL32K _OUT Input to the 32 768kHz main clock XTAL32K_IN Output from t...

Page 42: ...nual 9 Principles and Failure Analysis Issue 1 0 2012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 33 Figure 9 15 Flash memory circuit diagram 1 Figure 9 16 Flash memory circuit diagram 2 ...

Page 43: ...U8815 Maintenance Manual 9 Principles and Failure Analysis Issue 1 0 2012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 34 Figure 9 17 Flash memory circuit diagram 3 ...

Page 44: ...ash memory circuit diagram 4 Analysis The MSM7227A is able to visit the LPDDR2 through two high speed buses EBI1 The LPDDR2 is connected to the MSM8255 0 in PoP Package on package mode Meanwhile the MSM7227A can also visit the external storage eMMC through a low speed bus EBI2 as shown in the following figure Figure 9 19 shows the analysis of the U8815 memory interface ...

Page 45: ...han 100 mA Solution Upgrade or reinstall the firmware of the handset and check whether the VREG_DCDC_2P85 voltage and peripheral components of the flash memory are normal If the problem persists replace U1700 Table 9 4 describes the signals in the circuit diagram in this section Table 9 4 Description of the signals in the circuit diagram in this section Signal Description Reference Measurement or ...

Page 46: ...wer supply of Flash memory 2 85 V VREG_S3 Power supply 1 8 V MSM_RESOUT_N Reset signal VPH_PWR System power supply supplying power to the 2 85 V DC chip 9 3 RF Unit Figure 9 20 shows the transmitting and receiving circuit block diagram Figure 9 20 Transmitting and receiving circuit block diagram Circuit Analysis The model of the RF switch behind the main antenna is LMSP4LMA_550_A and the control l...

Page 47: ...800 1900 TX 1 0 0 0 GSM850 RX 0 1 1 0 GSM900 RX 0 1 0 0 GSM1800 RX 0 0 1 0 GSM1900 RX 0 0 0 0 W1900 AWS_TX RX 1 0 1 0 W850 900_TX RX 1 0 1 1 W2100_TX RX 1 1 1 0 NOTE The voltage of L in the preceding table ranges from 0 to 0 2 V The voltage of H ranges from 1 8 to 3 0 V These control signals are provided by MSM722A 9 3 2 Power Amplifier Circuit block diagram The following figures show various powe...

Page 48: ...rinciples and Failure Analysis Issue 1 0 2012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 39 Figure 9 22 WCDMA 850 PA diagram Figure 9 23 WCDMAPCS PA diagram Figure 9 24 GSM Quad_band_PA diagram ...

Page 49: ...ei Technologies Co Ltd 40 Figure 9 25 UMTS IMT RX INTERSTAGE CHAIN diagram Figure 9 26 Diagram of dualband RF transmitting and receiving by using RTR6285A chip 9 3 3 Troubleshooting Troubleshooting process Failure Receiving failure Solution use W2100 as an example Figure 9 27 shows the troubleshooting process for receiving failure ...

Page 50: ...ck U3404 Check U3201 when the handset is not connected to the RF cable Check U401 Y Y Y N N N Check U3202 and U401 Check whether the IQ signal of U3901 and the power supply voltage are normal Y N Check U3201 Check U3901 Failure of the W2100 receiving channel End Y Check whether signals on pins 1 and 8 of U3401 are normal and the maximum insertion loss is smaller than or equal to 2 3 dB NOTE Check ...

Page 51: ...0 In WCDMA900 just replace the U3404 detection with U4202 detection In GSM just replace the U3404 detection with U3501 detection Transmission failure Maintenance procedure for transmission failure in W2100 W900 GSM900 and GSM1800 Maintenance procedure for transmission failure in W2100 Ensure that the SIM card and antenna are installed properly and then detect the handset according to the following...

Page 52: ...Y Y N N N Check U3202 and U401 Check whether the IQ signal of U3901 and the power supply voltage are normal Y N Check U3201 Check U3901 Failure of the W2100 transmission channel End In W900 just replace the U3302 detection with U3401 detection In GSM900 or GSM1800 just replace the U3302 detection with U3401 detection Table 9 7 describes the signals in the circuit diagram in this section Table 9 7 ...

Page 53: ... data line None PRX_Q_P IQ signal of the primary receiving channel None PRX_Q_M IQ signal of the primary receiving channel None PRX_I_P IQ signal of the primary receiving channel None PRX_I_M IQ signal of the primary receiving channel None DRX_GPS_Q_P IQ signal of the secondary receiving channel None DRX_GPS_Q_M IQ signal of the secondary receiving channel None DRX_GPS_I_P IQ signal of the seconda...

Page 54: ...al 9 Principles and Failure Analysis Issue 1 0 2012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 45 Figure 9 29 Display screen circuit diagram 1 Figure 9 30 Display screen circuit diagram 2 ...

Page 55: ...f the U8815 employs the MIPI interface It requires only two pairs of low voltage differential signal LVDS cables and a pair of power cables and supports 60 Hz refreshment rate With frame synchronization function the LCD uses MDP_VSYNC of GPIO_097 as the data transmission synchronization signal to avoid LCD breakage Troubleshooting Process Failure The handset can be powered on but its LCD is blank ...

Page 56: ...air N Y Y Y N N Check L1201 and U1201 Is the J1201connector properly soldered Y N End Repair J1201 Table 9 8 describes the signals in the circuit diagram in this section Table 9 8 Description of the signals in the circuit diagram in this section Signal Description Reference Measurement or Wave Form VREG_L12_2P85 LCD analog voltage 2 85 VREG_S3 I O connector digital voltage 1 8 MIPI_DSI_LANE2_P Dif...

Page 57: ... 8 MIPI_DSI_CLK_P Clock differential signal 1 8 MIPI_DSI_CLK_N Clock differential signal 1 8 9 4 2 Vibration Circuit block diagram Figure 9 33 shows the motor circuit diagram Figure 9 33 Motor circuit diagram Analysis The pin VIB_DRV_N of PM8029 is the driver pin of the actuator and the motor is installed on the PCBA When the motor is not vibrating VPH_PWR and VIB_DRV_N are both at high level Trou...

Page 58: ...er supply Motor vibration failure Return the handset to the factory for repair N N N Y Y N Validate after soldering End Is the motor vibration normal after the motor is replaced Y Y End End Table 9 9 describes signals in the circuit diagram in this section Table 9 9 Description of the signals in the circuit diagram in this section Signal Description Reference Measurement or Wave Form VPH_PWR Main ...

Page 59: ... 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 50 The following figures show the call reception circuit diagrams Figure 9 35 Call reception circuit diagram 1 Figure 9 36 Call reception circuit diagram 2 Figure 9 37 Call reception circuit diagram 3 ...

Page 60: ...ion circuit diagram 4 Analysis Figure 9 39 shows the 7227A audio processing diagram Figure 9 39 7227A audio processing diagram U8815 provides three audio outputs 1 Receiver output outputting signal through PM8029 2 Speaker output output by PM8029 to the speaker through the power amplifier 3 Headset output U8815 adopts binaural headset Table 9 10 describes the three audio outputs ...

Page 61: ...P_1_OP The signal is output to the receiver None EAR1_AMP_1_ON The signal is output to the receiver None SPK_OUT_L_P This signal is output to the speaker through the power amplifier None SPK_OUT_L_M This signal is output to the speaker through the power amplifier None Troubleshooting process Failure After a call is established no sound can be heard by the other party Solution Figure 9 40 shows the...

Page 62: ...ection line normal Re solder the receiver connection line After a call is established no sound is heard by the other party N Y N Y N N Adjust the volume to check whether the setting is normal Does the handset misjudge headset insertion Y Y Check and repair the headset connector End Is the receiver volume setting normal after the receiver is replaced N Y End Do the U2002 neighboring circuits encoun...

Page 63: ...012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 54 Figure 9 41 shows the primary handset microphone circuit diagram Figure 9 41 Primary handset microphone circuit diagram Figure 9 42 shows the secondary handset microphone circuit diagram ...

Page 64: ...U8815 board collect different audio signals by processing the MICs on the handset upper and lower parts filtering the environmental noises The two microphones are powered by means of HSED_MICBIAS headset MIC PM8029 HSED_BIAS1 SND_MICBIAS secondary MIC PM8029 HSED_BIAS2 and MSM_MICBIAS primary MIC 7227A MIC_BIAS Troubleshooting Process Failure No sound is picked up or transmitted during a call Solu...

Page 65: ... repair N N N Y Y N End Is the call normal after the MIC is replaced Y Y End End After a call is established no sound is heard by the other party Table 9 11 describes signals in the circuit diagram in this section Table 9 11 Description of the signals in the circuit diagram in this section Signal Description Reference Measurement or Wave Form MIC1_P Input from the primary microphone None MIC1_N In...

Page 66: ..._DETECT_N GPIO_026 Before connecting the headset HS_DETECT_N is pulled up to high level by VREG_S3 After connecting the headset HS_DETECT_N is dropped down to low level The headset MIC is supplied with power by MIC_BIAS1 PM8029 HSED_BIAS1 and it is used for headset answer detection The headset of the U8815 is compatible with two line sequences The iphone s headset line sequence is compatible by de...

Page 67: ...ed on sound is heard over the headset Return the headset to the factory for repair Table 9 12 describes the signals in the circuit diagram in this section Table 9 12 Description of the signals in the circuit diagram in this section Signal Description Reference Measurement or Wave Form FM_ANT FM antenna None HPH_OUT_L Stereo headset output None HPH_OUT_R Stereo headset output None HSED_MICBIAS Head...

Page 68: ...46 shows the SIM card circuit diagram Figure 9 46 SIM card circuit diagram Analysis The signal input and output of the U8815 SIM card interface are controlled by PM8029 Troubleshooting Process Failure The handset cannot detect the UIM card Solution Check whether the UIM card holder functions properly Figure 9 47 shows the troubleshooting process for the UIM card detection failure ...

Page 69: ...he handset to the factory for repair N Y Y Y N N End Check VDD SIM1 Table 9 13 describes the signals in the circuit diagram in this section Table 9 13 Description of the signals in the circuit diagram in this section Signal Description Reference Measurement or Wave Form VREG_L16_UIM1 Power supplied to the UIM card 2 85 V UIM1_DATA UIM card data signals None UIM1_CLK The UIM card clock signals None...

Page 70: ...ion for upgrading the phone s firmware reading information from the phone between the phone and the computer Troubleshooting Process Failure The handset cannot be charged or detected by a computer Solution Clean re solder or replace the USB connector Table 9 14 describes the signals in the circuit diagram in this section Table 9 14 Description of the signals in the circuit diagram in this section ...

Page 71: ...pyright Huawei Technologies Co Ltd 62 Figure 9 49 microSD card connector circuit diagram Analysis U1601 is added to prevent electrostatic and for EMI filtering Troubleshooting Process Failure The microSD card cannot be detected or read Solution Figure 9 50 shows the troubleshooting process for micorSD card read failure ...

Page 72: ...re Can the Micro SD card be read after the Micro SD card is replaced Are the signals on the two sides of the U1601 connected Can the Micro SD card be read after the software is updated End Re solder U1601 The Micro SD card cannot be read The Micro SD card cannot be read Return the handset to the factory for repair N Y N Y N Y 9 4 9 FM The following figures show the FM circuit diagrams Figure 9 51 ...

Page 73: ...FM signals The BCM4330 chip integrates the functions of FM BT and WLAN For information about the FM antenna see description about the headset connector The FM radio uses a headset as the antenna Therefore a stereo headset must be inserted for the FM radio to function Troubleshooting Process Failure The FM radio fails to function Solution If signals are available but no sound is heard check the hea...

Page 74: ...el search effect good after the software is updated End End End The FM channel search effect is not good Return the headset to the factory for repair N N N Y Y Y Table 9 15 describes the signals in the circuit diagram in this section Table 9 15 Description of the signals in the circuit diagram in this section Signal Description Reference Measurement or Wave Form FM_ANT FM antenna None SR_AVDD2P5 S...

Page 75: ...ntial Copyright Huawei Technologies Co Ltd 66 10 Solder Points on the PCB and BGA Chip The following figures show the solder points on the PCB and BGA chip Red R 255 G 0 B 0 Vacant point Green R 0 G 255 B 0 Ground point Blue R 0 G 0 B 255 Solder point Figure 10 1 Diagram 1 of the solder points on the PCB and BGA chip ...

Page 76: ...e PCB and BGA Chip Issue 1 0 2012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 67 Figure 10 2 Diagram 2 of the solder points on the PCB and BGA chip Figure 10 3 Diagram 3 of the solder points on the PCB and BGA chip ...

Page 77: ...nce Manual 10 Solder Points on the PCB and BGA Chip Issue 1 0 2012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 68 Figure 10 4 Diagram 4 of the solder points on the PCB and BGA chip ...

Page 78: ...0 2012 02 13 Huawei Proprietary and Confidential Copyright Huawei Technologies Co Ltd 69 11 Performance Test 11 1 Keys Figure 11 1 shows the U8815 handset keys Figure 11 1 U8815 handset key On Off Unlock key Headset holder Volume Volume Menu Homepage Back ...

Page 79: ... works normally 7 Touch panel test Touch black point areas according to the screen prompt 8 Proximity light test Shield the proximity light window to check whether the screen display changes If the answer is displayed during the call the environmental light displays a luminous intensity value 9 Motor vibration test Check whether the motor vibrates and has noises 10 SPK external play test Check whe...

Page 80: ...rd and battery on the phone 2 Press the Power key to power the phone on 3 Check whether the signal strength displayed on the LCD is normal 4 Make a call to a fixed line phone and check the voice quality during the call 5 If no problem is found during the test finish the voice call test If any problem is found troubleshoot the phone or send it to an advanced service site for repair ...

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