LG U8550 Service Manual page 3

Table Of Contents
3.8.3 Frequency Generation .....................92
4. TROUBLE SHOOTING ...................94
4.1 Power ON Trouble .................................94
4.2 USB Trouble ..........................................96
4.3 SIM Detect Trouble ................................97
4.4 TransFlash Trouble................................98
4.5 Keypad Trouble......................................99
4.6 1.3M Camera Trouble ..........................101
4.7 VGA Camera Trouble ..........................103
4.8 Main LCD Trouble................................105
4.9 Sub LCD Trouble .................................107
4.10 Keypad Backlight Trouble ..................109
4.11 Camera Flash Trouble .......................111
4.12 Audio Trouble.....................................113
4.12.1 Receiver.......................................113
4.12.2 Speaker .......................................117
4.12.3 Microphone ..................................121
4.12.4 Headset - Receiver ......................125
4.12.5 Headset - MIC..............................126
4.12.6 Headset .......................................127
4.13 Charger Trouble.................................128
4.14 RF Component...................................130
4.15 Procedure to check ............................132
4.16 Checking Common Power
Source Block......................................133
4.17 Checking VCXO Block .......................140
4.18 Checking Ant. SW Module Block .......145
4.19 Checking Antenna Switch Block input
logic....................................................146
4.19.1 Mode Logic by TP Command ......146
4.19.2 Checking Switch Block
power source ...............................148
4.20 Checking WCDMA Block ...................153
4.20.1 Checking VCXO Block .................154
4.20.2 Checking Ant. SW module ...........154
4.20.3 Checking Control Signal ..............154
4.20.4 Checking RF TX Level .................156
4.20.5 Checking PAM Block ...................159
4.20.6 Checking RX I,Q ..........................162
4.21 Checking GSM Block .........................164
4.21.1 Checking Regulator Circuit ..........165
4.21.2 Checking VCXO Block .................165
4.21.3 Checking Ant. SW Module ...........165
4.21.4 Checking Control Signal ..............166
4.21.5 Checking RF Tx Path...................168
4.22 Checking Bluetooth Block ..................181
5. BLOCK DIAGRAM ........................185
5.1 GSM & WCDMA RF Block...................185
6. DOWNLOAD .................................187
6.1 The Purpose of Downloading
Software ............................................187
6.2 Download Environment Setup .............187
6.3 U8XXX Download ................................188
7. CALIBRATION ..............................200
7.1 General Description ............................ 200
7.2 XCALMON Environment ..................... 200
7.2.1 H/W Environment.......................... 200
7.2.2 S/W Environment .......................... 200
7.2.3 Configuration Diagram of
Calibration Environment................ 200
7.3 Calibration Explanation ....................... 201
7.3.1 Overview ....................................... 201
7.3.2 Calibration Items ........................... 201
7.3.3 EGSM 900 Calibration Items ........ 202
7.3.4 DCS 1800 Calibration Items ......... 207
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