LG S55A3-D Service Manual

3-9
ONE POINT REPAIR GUIDE
8. S(SHUT DOWN) PROTECTION
8-1. Solution
Replace IC703 (AMP IC) on MAIN board.
8-2. How to troubleshoot (Countermeasure)
1) After MAIN SET power off, check Red LED blink at intervals of 1 sec. (D Protection or S Protection)
2) Turn MAIN SET power on again.
3) Check PVDD voltage (24 V) of CN601 pin4, 5, 6.
- If PVDD voltage has 8.5 V under, refer to SMPS board repair guide. (page 3-2.)
4) Check GVDD, VDD voltage (12 V) of IC703 pin1, 2.
- If GVDD, VDD voltage has 8.5 V under, refer to 12 V no power repair guide. (page 3-3.)
5) Check impedance (4 Ω) of speaker unit.
- If impedance of speaker unit has 1 Ω under, replace speaker unit.
6) If check point 3), 4), 5) is ok, replace IC703 (AMP IC) on MAIN bottom board.
8-3. Service hint (Any picture / Remark)
< MAIN board top view >
< MAIN board bottom view >
CN601
CN601
IC703 (AMP IC)
IC703 (AMP IC)

LG S55A3-D Specifications

General

Brand	LG
Model	S55A3-D
Category	Speaker System
Language	English