Sound In Portable Mode - LG NP7550 Service Manual

2. NO SOUND IN PORTABLE MODE
No sound problem occurs in portable mode.
2-1. Solution
Check and replace IC500 on main board.
2-2. How to troubleshoot (Countermeasure)
1) Check solder of JK300.
2) Check input voltage of IC500 (L503, C504).
  L503 should be 3.3 V L504 should be 5 V.
3) Check if signal enters pin13 and pin14 of IC500.
Check if signal comes out from pin8 and pin9 of IC500.
  If it doesn't work, replace IC500.
2-3. Service hint (Any picture/ Remark)
IC500 IC500
ONE POINT REPAIR GUIDE
< Main board bottom view >
< Jack board top view >
JK300 JK300
3-3