LG SJ5 Service Manual page 30

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 ......................................................................................................................... 3-13
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 3-16
1. CRYSTAL .............................................................................................................................................. 3-16
2. FLASH MEMORY ................................................................................................................................. 3-16
3. TACT KEY ............................................................................................................................................. 3-17
4. USB ....................................................................................................................................................... 3-18
5. REMOTE CONTROL ............................................................................................................................ 3-19
6. OPTICAL ............................................................................................................................................... 3-20
7. PORTABLE ........................................................................................................................................... 3-21
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-23
1. IC VOLTAGE ......................................................................................................................................... 3-23
2. CAPACITOR VOLTAGE ....................................................................................................................... 3-24
3. CONNECTOR VOLTAGE ..................................................................................................................... 3-24
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-25
1. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 3-25
2. FRONT P. C. BOARD DIAGRAM ......................................................................................................... 3-27
3. KEY P. C. BOARD DIAGRAM .............................................................................................................. 3-27
SECTION 3
ELECTRICAL
CONTENTS
3-1