LG Electronics U250 4.19 Main microphone

4. TROUBLE SHOOTING

- 113 -

4.19 Main microphone

MIC400 →MIC1P, MIC1N (MSM6245)

Start

MIC_BIAS(C416)

is 1.8V Change main board

Make a call

Change the MIC

YES

Change the Main board

Make sound to MIC

Work well? END

YES

Sine wave appears at

C418/C419?

Contents

Main Table Of Contents 1. INTRODUCTION .............................. 5 2. PERFORMANCE...............................7 3. TECHNICAL BRIEF ........................17 4. TROUBLE SHOOTING ...................73 Page 1. INTRODUCTION 1. INTRODUCTION 1.1 Purpose 1.2 Regulatory Information A. Security 1. INTRODUCTION 2.1 System Overview 2. PERFORMANCE 2.2 Usable environment 1) Environment 2) Environment (Accessory) 2.3 Radio Performance 1) Transmitter - GSM Mode Page Page 2) Transmitter - WCDMA Mode 3)Receiver - GSM Mode 4) Receiver - WCDMA Mode 2.4 Current Consumption 1) U250/KU250 Current Consumption 2.5 RSSI BAR 2.6 Battery BAR 2.7 Sound Pressure Level 2.8 Charging 3.1 General Description 3. TECHNICAL BRIEF Page 3.2 GSM Mode 3.2.1 GSM Receiver Page Page 3.2.2 GSM Transmitter 3.3 UMTS Mode 3.3.1 Receiver 3.3.2 Transmitter Page 3.4 LO generation and distribution circuits PA_R0 - 25 - 3.5 Off-chip RF Components 3.5.1 WCDMA PAM (U103: WS2512-TR1G) 3.5.2 VCTCXO (X100 : DSA321SCE-19.2M) 3.5.3 Front-End Module (U500 : D5011) 3.5.4 PMIC Functional Block Diagram (U300 : PM6650-2M) Page Page 3.5.5 GSM PAM (U101 : SKY77318) GSM_PA_RA GSM_PA_EN GSM_PA_BAND SKY77318 3.5.6 UMTS Duplexer(FL104:ACMD-7602) 3.5.7 UMTS Rx RF filter (FL103 : EFCH2140TDE1) 3.5.8 Bluetooth (M100 : LBRQ-2B43A) 3. BB Technical Description 3.6 Digital Baseband(DBB/MSM6245) 3.6.1 General Description A. Features(MSM6245) - 35 - MSM6245 PM6650 -2M GSM VCO GSM Block WCDMA Block MSM6245 PM6650 NAND Flash 512Mbit SDRAM 512Mbit LCD (1.76inch) 3.8 Subsystem(MSM6245) 3.8.1. ARM Microprocessor Subsystem 3.8.2. WCDMA R99 features 3.8.3. GSM features 3.8.4. GPRS features 3.8.5. EDGE features 3.8.6. MSM6245 device audio processing features 3.8.7. MSM6245 microprocessor subsystem 3.8.8. Supported interface features 3.8.9. Supported multimedia features Page Page 3.8.10. Stereo Wideband CODEC 3.8.11. Vocoder Subsystem 3.8.12. ARM Microprocessor subsystem 3.8.13. Mode Select and JTAG Interfaces Page 3.9 Power Block 3.9.1. General 3.9.2. PM6650 Page 3.9.3. Charging control Trickle Charging Constant Current Charging Constant Voltage Charging 3.10 External memory interface EBI1 EBI2 3.11 H/W Sub System 3.11.1. RF Interface RF Figure 1.15 Schematic of RF Interface of MSM6245 - 52 - B. the others 3.11.2. MSM Sub System MSM6245 PM6650 USIM - 55 - C336 4.7u 12 R309 2.2K 1608 3.11.3 HKADC(House Keeping ADC) - 57 - 3.11.4. Key Pad PM_ON_SW_N END Figure 1.20 END Keypad Circuit Table. Key Matrix Mapping Table 3.11.5 Camera Interface MEGA CAMERA CONNECTOR VT_CAMERA_CONNECTOR Figure 1.21 Camera Socket Type Connector - 58 - Page Page - 61 - 3.11.6 Keypad Light Figure 1.22 Schematic of KEY back light circuit (KEY side) KEY_BACK_LIGHT LED(8EA) - 62 - 3.11.7. LCD Module (NM176CN1 : Tovis) Figure 1.23 Interface between LCD Module and MAIN PCB. FL405 FL403 FL402 3.11.8.1. Audio Signal Processing & Interface - 64 - MSM6245 CODEC pins AUDIO Near to MSM Figure 1.25 Audio part schematics Figure 1.26 Audio part schematics MIC - 66 - Audio part schematics Audio AMP NCP2890DMR2 U402 - 67 - 3.11.8.2. Audio Mode There are three audio modes (Voice call, speaker phone, MIDI/MP3). Audio & Sound Main Component There are 6 main components in U250/KU250. Table. Audio Mode Table. Audio main component list 3.12 Main Features 1. LG-U250/KU250 Main features 2. U250/KU250 Main Component RF SW100 Logic / Audio Logic Page Page - 75 - 4.2 SIGNAL PATH_UMTS RF 4.3 SIGNAL PATH_GSM RF - 76 - - 77 - 4.4 Checking VC-TCXO Block Test Point of the VC-TCXO Block TCXO U104 X100 TP2 TP1 TP3 Page - 79 - 4.5 Checking Front-End Module Block Test Point of the Front-End Module Block ANT_SEL0 ANT_SEL1 VREG_RF_SMPS Page - 81 - 4.6 Checking UMTS Block For testing, Max power of UMT 2100 is needed. PA_R0 U500 11 Page Page - 84 - 4.6.3 Checking RF Rx Level PA_R0 L102 G2 RF ANT G1 Page Page - 87 - 4.7.1 Checking RF Tx level 0 ANT_SEL1 GSM_PA_RAMP U101 Page - 89 - 4.7.4 Checking PAM Block GSM_PA_EN GSM_PA_BAND SKY77318 FL1 4.7.5 Checking RF Rx Block Schematic of GSM900/DCS/PCS Rx Block - 90 - TP1. DCS RX INPUT TP2. PCS RX INPUT TP3. GSM RX INPUT ANT_SEL0 Page 4.8 Checking Bluetooth Block Test Point of the Bluetooth Block LBRQ-2B43A ANT103 TP1 Page 4.9 Power ON Troubleshooting Page 4.10 Charger Troubleshooting CHARGER - 97 - [ Charger Troubleshooting Flow ] Page 4. BB Trouble Shooting 4.11 USB Troubleshooting - 100 - 4.12 SIM Detect Troubleshooting - 101 - 1VREG_USIM_2.85V 2USIM_P_RST_N USIM_P_CLK Figure. USIM part schematics 3 7USIM_P_DATA 1 USIM 4.13 Camera Troubleshooting 4.13.1 MEGA CAMERA 4.13.2 VGA CAMERA - 104 - C347 U303 C349 CAMERA LDO - 105 - 4.14 Keypad Backlight Troubleshooting +VPWR Figure.Keypad backlight LED part Key Pad Back Light is on as below : Key pressing KYBD_BACKLIGHT go to 0V MAIN Key Backlight LED On KEY_BACK_LIGHT LED(8EA) 4.15 Main LCD Troubleshooting Main LCD control signals are generated by MSM6245. The signal path is : MSM6245 CN400 LCD Module - 107 - 4.16 Receiver Path MSM6245 EAR1ON/EAR1OP R421,R422 Analog Switch(U401) Receiver Page - 109 - 4.17 Headset path MSM6245 HPH_R, HPH_L C402/C401 R407/R406 CN401 (MMI Connector) Page - 111 - 4.18 Speaker phone path Page - 113 - 4.19 Main microphone MIC400 MIC1P, MIC1N (MSM6245) Page - 115 - 4.20 Headset microphone Headset C210/C211 MIC2P, MIC2N (MSM6245) Page 4.21 Vibrator Page 5. DOWNLOAD 5.1 U250/KU250 DOWNLOAD 5.1.1 Introduction 5.1.2 Downloading Procedure 5.1.2.1 Connecting to PC 1) 2) 3) 6) 4) 5) 7) 5.1.2.2 Choosing image files Page Page 5.1.2.3 Downloading Page Page Page 5.1.3 Troubleshooting Download Errors 5.1.3.1 When the phone does not work Page Page Page 5.1.4 Caution D:\LGMDP\004400-01-429926\_COM14_ Page Page Page Page Page 6. BLOCK DIAGRAM - 139 - Main RF signal Control signal Page Page Page - 143 - DCS ANT_SEL1 GSM_PA_EN GSM_PA_BAND - 144 - ADC USB_D- VBATT UART_TXD - 145 - LCD LDO REV_1.0 MEMORY 3/4 - 146 - VT_CAMERA_CONNECTOR 63 4/4 KEY / MMI Page Page - 149 - 9. Calibration & RF Auto Test Program (Hot Kimchi) 9.1 Configuration of HOT KIMCHI 9.1.1 Configuration of directory - 150 - - 151 - 9.2 How to use HOT KIMCHI Page Page 10. Factory Test Mode 10.2. WCDMA Test Mode 10. Factory Test Mode 10.3. GSM Test Mode - 157 - 11. EXPLODED VIEW & REPLACEMENT PART LIST 11.1 EXPLODED VIEW Page - 159 - 11.2 Replacement Parts <Mechanic component> Note: This Chapter is used for reference, Part order - 160 - - 161 - 11.2 Replacement Parts <Main component> Note: This Chapter is used for reference, Part order - 162 - - 163 - - 164 - - 165 - - 166 - - 167 - - 168 - - 169 - - 170 - - 171 - - 172 - Page - 174 - 11.3 Accessory Note:This Chapter is used for reference, Part order