LG NP8540 Service Manual page 24

ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. IF NOT BOOTING WHEN YOU TURN ON THE SET. AND LED DOESN'T TURN ON ....................... 3-2
2. NO SOUND FROM THE SPEAKER ....................................................................................................... 3-4
3. IF NOT BOOTING WHEN YOU TURN ON THE SET ............................................................................ 3-5
4. WIRED NETWORK CONNECTION ERROR ....................................................................................... 3-12
5. PORTABLE FUNCTION DOESN'T WORKING .................................................................................... 3-13
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................. 3-14
1. POWER SUPPLY ON MAIN BOARD ................................................................................................... 3-14
2. MICOM .................................................................................................................................................. 3-17
3. LED ....................................................................................................................................................... 3-18
4. AUDIO ................................................................................................................................................... 3-19
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 3-22
1. MICOM .................................................................................................................................................. 3-22
2. AMP ...................................................................................................................................................... 3-22
3. MPEG .................................................................................................................................................... 3-23
4. BLUETOOTH ........................................................................................................................................ 3-25
5. Wi-Fi ...................................................................................................................................................... 3-25
WIRING DIAGRAM .......................................................................................................................................... 3-27
BLOCK DIAGRAM .......................................................................................................................................... 3-29
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-31
1. MAIN - MICOM/ ADC/ AMP CIRCUIT DIAGRAM ................................................................................ 3-31
2. MAIN - MPEG CIRCUIT DIAGRAM ...................................................................................................... 3-33
3. MAIN - MEMORY & HW TRAP CIRCUIT DIAGRAM ........................................................................... 3-35
4. VOLUME CIRCUIT DIAGRAM ............................................................................................................. 3-37
5. LED CIRCUIT DIAGRAM ...................................................................................................................... 3-39
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-41
1. ICs ......................................................................................................................................................... 3-41
2. CAPACITORS ....................................................................................................................................... 3-41
3. CONNECTORS ..................................................................................................................................... 3-41
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-43
1. MAIN P.C.BOARD ................................................................................................................................ 3-43
2. VOLUME P.C.BOARD .......................................................................................................................... 3-45
3. LED P.C.BOARD .................................................................................................................................. 3-45
SECTION 3
ELECTRICAL
CONTENTS
3-1