Troubleshooting Guide - LG StudioWorks 570LE Service Manual

TROUBLESHOOTING GUIDE

NO POWER
(POWER INDICATOR OFF)
CHECK J1'S
VOLTAGE
(24V) ?
YES
CHECK
U22 PIN5 VOLTAGE
(5V) ?
YES
CHECK
U17 Voltage
(5V) ?
YES
CHECK KEY CONTROL
CONNECTOR ROUTINE
NO
IS U5 PIN12
VOLTAGE REPEATED
AS PULSE SHAPE ?
NO
CHECK IIC LINE
CONNECTION
(U3, U1)
1. NO POWER
NO
NO
NO
NO
CHECK U4'S VCC,
XTAL, RESET
- 16 -
CHECK ADAPTER,
AND FIND OUT
A SHORT POINT
AS OPENING
EACH POWER LINE
CHECK U22, U11.
CHECK T1'S PRIMARY
COIL (OPEN CHECK)
NO PROBLEM
U13'S PIN11
0V ?
YES
CHECK U13, AND
CHECK 5VA LINE