LG NP8340 - SECTION 3 ELECTRICAL

3-1
SECTION 3
ELECTRICAL
CONTENTS
ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER PROBLEM (19 VA) ............................................................................................................ 3-2
2. IF NOT BOOTING WHEN YOU TURN ON THE SET (LED DOES NOT TURN ON) ............................ 3-3
3. IF NOT BOOTING WHEN YOU TURN ON THE SET (IC802) ............................................................... 3-4
4. NO SOUND FROM THE SPEAKER ....................................................................................................... 3-5
5. IF NOT BOOTING WHEN YOU TURN ON THE SET. AND LED DOESN’T TURN ON ....................... 3-6
6. IF NOT BOOTING WHEN YOU TURN ON THE SET (IC800) ............................................................... 3-7
7. IF NOT BOOTING WHEN YOU TURN ON THE SET (IC103) ............................................................... 3-8
8. IF NOT BOOTING WHEN YOU TURN ON THE SET (MPEG IC) ......................................................... 3-9
9. IF NOT BOOTING WHEN YOU TURN ON THE SET (DDR IC) .......................................................... 3-10
10. IF NOT BOOTING WHEN YOU TURN ON THE SET (NAND FLASH MEMORY IC) ......................... 3-11
11. IF NOT BOOTING WHEN YOU TURN ON THE SET (CRYSTAL) ...................................................... 3-12
12. WIRED NETWORK CONNECTION ERROR ....................................................................................... 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 .......................................................................................................................................... 3-25
BLOCK DIAGRAMS ........................................................................................................................................ 3-27
1. OVERALL BLOCK DIAGRAM .............................................................................................................. 3-27
2. POWER BLOCK DIAGRAM ................................................................................................................. 3-29
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-31
1. MAIN - SMPS CIRCUIT DIAGRAM ...................................................................................................... 3-31
2. MAIN - MICOM/ AMP CIRCUIT DIAGRAM .......................................................................................... 3-33
3. MAIN - MPEG CIRCUIT DIAGRAM ...................................................................................................... 3-35
4. MAIN - MEMORY & HW TRAP CIRCUIT DIAGRAM ........................................................................... 3-37
5. VOLUME TOUCH & KEY1 CIRCUIT DIAGRAM .................................................................................. 3-39
6. LED CIRCUIT DIAGRAM ...................................................................................................................... 3-41
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-43
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-45
1. MAIN P.C.BOARD ................................................................................................................................ 3-45
2. TOUCH P.C.BOARD ............................................................................................................................. 3-47
3. LED P.C.BOARD .................................................................................................................................. 3-47