LG LAS350B - Operating Your Sound Bar; Core Sound Control and Information

3-1
SECTION 3
ELECTRICAL
CONTENTS
ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER PROBLEM (PVDD) ............................................................................................................ 3-2
2. POWER ON ERROR .............................................................................................................................. 3-3
3. NO SOUND (PORTABLE FUNCTION) .................................................................................................. 3-4
4. NO BLUETOOTH .................................................................................................................................... 3-5
5. NO SOUND (OPTICAL) .......................................................................................................................... 3-6
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................... 3-7
1. POWER SUPPLY CIRCUIT .................................................................................................................... 3-7
2. FRONT CIRCUIT .................................................................................................................................... 3-8
3. TEST & DEBUG FLOW ........................................................................................................................ 3-10
4. AMP PROTECTION .............................................................................................................................. 3-13
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 3-14
1. CRYSTAL .............................................................................................................................................. 3-14
2. FLASH MEMORY ................................................................................................................................. 3-15
3. TACT KEY ............................................................................................................................................. 3-16
4. USB ....................................................................................................................................................... 3-17
5. REMOTE CONTROL ............................................................................................................................ 3-18
6. OPTICAL ............................................................................................................................................... 3-19
7. PORTABLE ........................................................................................................................................... 3-20
8. AUDIO PWM ......................................................................................................................................... 3-21
9. AUDIO AMP .......................................................................................................................................... 3-23
WIRING DIAGRAM .......................................................................................................................................... 3-25
BLOCK DIAGRAM .......................................................................................................................................... 3-27
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-29
1. SMPS CIRCUIT DIAGRAM .................................................................................................................. 3-29
2. MAIN - DSP CIRCUIT DIAGRAM ......................................................................................................... 3-31
3. MAIN - POWER CIRCUIT DIAGRAM ................................................................................................... 3-33
4. MAIN - PWM & AMP CIRCUIT DIAGRAM ........................................................................................... 3-35
5. DISPLAY/ KEY/ USB CIRCUIT DIAGRAM ........................................................................................... 3-37
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-39
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-41
1. SMPS P. C. BOARD DIAGRAM ........................................................................................................... 3-41
2. MAIN P. C. BOARD DIAGRAM ............................................................................................................ 3-43
3. DISPLAY P. C. BOARD DIAGRAM ...................................................................................................... 3-45
4. KEY P. C. BOARD DIAGRAM .............................................................................................................. 3-45
5. USB P. C. BOARD DIAGRAM .............................................................................................................. 3-45