Troubleshooting Guide - LG StudioWorks 560LS Service Manual

NO POWER
(POWER INDICATOR OFF)
CHECK J1'S
VOLTAGE
(24V) ?
YES
CHECK
U4 PIN 8 VOLTAGE
(5V) ?
YES
CHECK
U5 Voltage
(5V) ?
YES
CHECK KEY CONTROL
CONNECTOR ROUTINE
NO
IS U3 PIN12
VOLTAGE REPEATED
AS PULSE SHAPE ?
NO
CHECK IIC LINE
CONNECTION
(U4, U1)

TROUBLESHOOTING GUIDE

1. NO POWER
NO
NO
NO
NO
CHECK U3'S VCC,
XTAL, RESET
- 14 -
CHECK ADAPTER,
AND FIND OUT
A SHORT POINT
AS OPENING
EACH POWER LINE
CHECK U4.
CHECK L11
(OPEN CHECK)
NO PROBLEM
U13'S PIN11
0V ?
YES
CHECK U13, AND
CHECK 5VA LINE