LG CU920 User Manual

- 3 -
1. INTRODUCTION .............................. 5
1.1 Purpose................................................... 5
1.2 Regulatory Information............................ 5
2. PERFORMANCE...............................7
2.1 System Overview.....................................7
2.2 Usable environment.................................8
2.3 Radio Performance..................................9
2.4 Current Consumption.............................16
2.5 RSSI BAR ..............................................16
2.6 Battery BAR ...........................................17
2.7 Charging ................................................17
2.8 Sound Pressure Level............................18
3. TECHNICAL BRIEF ........................19
3.1 General Description ...............................19
3.2 GSM Mode.............................................21
3.3 UMTS Mode...........................................25
3.4 LO generation and distribution circuits...28
3.5 Off-chip RF Components .......................29
3.6 Digital Baseband (MSM6281)................46
3.7. Subsystem(MSM6281) .........................48
3.8 Power Block...........................................57
3.9 External memory interface.....................62
3.10 H/W Sub System..................................64
3.11 MAIN Features.....................................80
4. TROUBLE SHOOTING ...................85
4.1 RF Component.......................................85
4.2 Component Description .........................88
4.3 WCDMA RF Signal Path........................89
4.4 GSM RF Signal Path..............................90
4.5 Checking VCTCXO Block ......................91
4.6 Checking Front-End Module Block ........94
4.7 Checking WCDMA Block .......................96
4.8 Checking GSM Block...........................101
4.9 Checking Bluetooth Block....................107
4.10 Power ON Troubleshooting................110
4.11 Charger Troubleshooting ...................112
4.12 USB Troubleshooting.........................115
4.13 USIM Detect Troubleshooting............117
4.14 Camera Troubleshooting ...................119
4.15 Keypad Backlight Troubleshooting ....121
4.16 LCD Troubleshooting.........................122
4.17 Receiver Path ....................................123
4.18 Headset path......................................125
4.19 Speaker phone path...........................127
4.20 Main microphone ...............................129
4.21 Headset microphone..........................131
4.22 Vibrator ..............................................133
4.23 Checking Media FLO Block ...............134
5. DOWNLOAD .................................138
5.1 Introduction ..........................................138
5.2 Downloading Procedure.......................138
5.3 Troubleshooting download errors ........152
5.4 Caution.................................................159
6. BLOCK DIAGRAM ........................160
7. Circuit Diagram ............................171
8. BGM Pin Map................................181
9. PCB LAYOUT................................183
10. Calibration & RF Auto Test
Program (Hot Kimchi)................187
10.1 Configuration of HOT KIMCHI ...........187
10.2 How to use HOT KIMCHI...................188
11. EXPLODED VIEW &
REPLACEMENT PART LIST ..... 191
11.1 EXPLODED VIEW ............................ 191
11.2 Replacement Parts
<Mechanic component>.................... 193
<Main component> ........................... 195
11.3 Accessory ......................................... 212
Table Of Contents
LGE Internal Use Only Copyright © 2008 LG Electronics. Inc. All right reserved.
Only for training and service purposes

LG CU920 Specifications

Camera

camera resolution	1600x1200, 1280x960, 640x480, 320x240, 160x120 Pixels
video resolution	320x240, 176x144 Pixels
zoom	Up to 2x

Power

standard battery	1, 000 mAh Li-Ion
talk time	Up to 3 Hours
standby time	Up to 10 Days & 10 Hours

Memory and Storage

internal memory	120MB
microSD memory port	Yes
USB mass storage	Yes

Weight and Dimensions

dimensions	4.25” (H) x 2.16” (W) x 0.51” (D)
weight	3.16 oz.
display size	3.00”