LG SH2 Service Manual

3-1
SECTION 3
ELECTRICAL
CONTENTS
ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER PROBLEM ......................................................................................................................... 3-2
2. SPEAKER NO SOUND ........................................................................................................................... 3-3
3. PORTABLE FUNCTION DOESN’T WORK (OPTIONAL PART) ............................................................ 3-4
4. BT FUNCTION DOESN’T WORK ........................................................................................................... 3-5
5. OPTICAL FUNCTION DOESN’T WORK ................................................................................................ 3-6
6. PROTECTION ......................................................................................................................................... 3-7
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................... 3-9
1. SMPS PART (POWER ON) .................................................................................................................... 3-9
2. SYSTEM PART ..................................................................................................................................... 3-10
3. NO AUDIO OUTPUT ............................................................................................................................ 3-11
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 3-12
1. SYSTEM PART-1 (X-TAL) .................................................................................................................... 3-12
2. SYSTEM PART-2 (I2S SIGNAL) .......................................................................................................... 3-13
3. SYSTEM PART-3 (I2C SIGNAL) .......................................................................................................... 3-14
WIRING DIAGRAM .......................................................................................................................................... 3-15
BLOCK DIAGRAMS ........................................................................................................................................ 3-17
1. SYSTEM BLOCK DIAGRAM ................................................................................................................ 3-17
2. POWER BLOCK DIAGRAM ................................................................................................................. 3-19
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-21
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-21
2. MAIN - AMP & POWER CIRCUIT DIAGRAM ...................................................................................... 3-23
3. MAIN - DSP CIRCUIT DIAGRAM ......................................................................................................... 3-25
4. JACK/ LED/ TOUCH KEY CIRCUIT DIAGRAM ................................................................................... 3-27
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-29
1. ICs ......................................................................................................................................................... 3-29
2. DIODES ................................................................................................................................................ 3-29
3. CAPACITORS ....................................................................................................................................... 3-30
4. CONNECTORS ..................................................................................................................................... 3-31
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-33
1. SMPS P. C. BOARD DIAGRAM ........................................................................................................... 3-33
2. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 3-33
3. JACK P. C. BOARD DIAGRAM ............................................................................................................ 3-37
4. LED P. C. BOARD DIAGRAM .............................................................................................................. 3-37
5. TOUCH KEY P. C. BOARD DIAGRAM ................................................................................................ 3-37

LG SH2 Specifications

General

Surround Sound	other
Inputs	optical digital audio
Outputs	none
HDMI Inputs	0
HDMI Outputs	0
USB Ports	0
Bluetooth	yes
Wireless Connectivity	bluetooth
Optical Audio Inputs	1
Remote Control	yes

Weight and Dimensions

Depth	3.5 inches
Height	2.4 inches
Width	34.6 inches
Net Weight	4 pounds