LG SJ9, Service Manual

Page: 38 / 81

3-1
SECTION 3
ELECTRICAL
CONTENTS
WIRING DIAGRAM ............................................................................................................................................ 3-2
BLOCK DIAGRAMS .......................................................................................................................................... 3-3
1. SYSTEM BLOCK DIAGRAM .................................................................................................................. 3-3
2. POWER BLOCK DIAGRAM ................................................................................................................... 3-4
ONE POINT REPAIR GUIDE ............................................................................................................................ 3-5
1. NO BOOTING WHEN YOU TURN THE UNIT ON, NO MESSAGE OR “HELLO”
ON FRONT PANEL ................................................................................................................................. 3-5
2. NO SOUND ............................................................................................................................................. 3-8
3. PROTECTION ERROR ......................................................................................................................... 3-12
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 3-15
1. CRYSTAL .............................................................................................................................................. 3-15
2. FLASH ................................................................................................................................................... 3-17
3. TACT KEY ............................................................................................................................................. 3-17
4. REMOTE CONTROL ............................................................................................................................ 3-19
5. OPTICAL ............................................................................................................................................... 3-20
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-21
1. ICs ......................................................................................................................................................... 3-21
2. CAPACITORS ....................................................................................................................................... 3-22
3. CONNECTORS ..................................................................................................................................... 3-22
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-23
1. SMPS P. C. BOARD DIAGRAM ........................................................................................................... 3-23
2. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 3-25
3. HDMI/ JACK P. C. BOARD DIAGRAM ................................................................................................. 3-29
4. FRONT P. C. BOARD DIAGRAM ......................................................................................................... 3-31
5. KEY P. C. BOARD DIAGRAM .............................................................................................................. 3-31