LG SN4A - Page 69

4-4
Copyright © 2021 LG Electronics Inc. All rights reserved.
Only for training and service purposes.
ONE POINT REPAIR GUIDE
3. POWER ON ERROR
MAIN SoC IC supply voltage check points
3-1. 3.3 VA
1) Check 3.3 VA at WCA603 and WL627.
2) Check 3.3V_PWM at pin5 of WIC605.
3) Check 3.3 VA at pin7, 8 of WIC603.
4) Check 3.3V_PWM at WL615 nearby WIC601.
If all voltages are OK, then check the PVDD voltage of woofer SMPS board.
< Woofer AMP board top view >
3.3V_PWM
3.3V_PWM
at WL615
at WL615
3.3 VA
3.3 VA
at WCA603, WL627
at WCA603, WL627
3.3 VA
3.3 VA
at pin7, 8 of WIC603
at pin7, 8 of WIC603
3.3V_PWM
3.3V_PWM
at pin5 of WIC605
at pin5 of WIC605