LG NP5550B Service Manual page 16

ONE POINT REPAIR GUIDE ............................................................................................................................ 3-2
1. NO POWER PROBLEM ......................................................................................................................... 3-2
2. NO SOUND IN PORTABLE MODE ........................................................................................................ 3-3
3. NO SOUND IN BLUETOOTH MODE ..................................................................................................... 3-4
4. NO CHARGING BATTERY ..................................................................................................................... 3-5
ELECTRICAL TROUBLESHOOTING GUIDE ................................................................................................... 3-6
1. POWER DSP/ AMP ................................................................................................................................ 3-6
2. AMP (PORTABLE MODE) ...................................................................................................................... 3-7
3. KEY/ LED ................................................................................................................................................ 3-8
4. CHARGING BATTERY ........................................................................................................................... 3-9
WAVEFORMS OF MAJOR CHECK POINT .................................................................................................... 3-10
WIRING DIAGRAM .......................................................................................................................................... 3-11
BLOCK DIAGRAMS ........................................................................................................................................ 3-13
1. SYSTEM BLOCK DIAGRAM ................................................................................................................ 3-13
2. POWER BLOCK DIAGRAM ................................................................................................................. 3-15
CIRCUIT DIAGRAMS ...................................................................................................................................... 3-17
1. MAIN - AMP CIRCUIT DIAGRAM......................................................................................................... 3-17
2. MAIN - POWER/ CHARGER CIRCUIT DIAGRAM ............................................................................... 3-19
3. KEY/ LED CIRCUIT DIAGRAM ............................................................................................................ 3-21
4. I/O JACK CIRCUIT DIAGRAM .............................................................................................................. 3-23
5. BATTERY JUCNTION CIRCUIT DIAGRAM ......................................................................................... 3-25
CIRCUIT VOLTAGE CHART ........................................................................................................................... 3-27
PRINTED CIRCUIT BOARD DIAGRAMS ....................................................................................................... 3-29
1. MAIN P. C. BOARD .............................................................................................................................. 3-29
2. KEY/ LED P. C. BOARD ....................................................................................................................... 3-31
3. I/O JACK P. C. BOARD ........................................................................................................................ 3-31
4. BATTERY JUCNTION P. C. BOARD ................................................................................................... 3-31
SECTION 3
ELECTRICAL
CONTENTS
3-1