Troubleshooting Guide - LG Flatron L1720B Service Manual

NO POWER
(POWER INDICATOR OFF)
CHECK J705
VOLTAGE
PIN5, PIN6 (5V)?
YES
CHECK
U501 PIN 8 Voltage
(5V) ?
YES
CHECK KEY CONTROL
CONNECTOR ROUTINE
IS U201
PIN114 (3.3V)
VOLTAGE REPEATED
AS PULSE
SHAPE ?
YES
CHECK IIC LINE
CONNECTION
(U501, U502)

TROUBLESHOOTING GUIDE

1. NO POWER
NO
NO
NO
CHECK U201 VCC,
BOARD, AND FIND
OUT A SHORT POINT
EACH POWER LINE
XTAL, RESET
CHECK POWER
AS OPENING
CHECK 5VS LINE
(OPEN CHECK)
NO PROBLEM