Troubleshooting Guide - LG FLATRON L1721B Service Manual

NO POWER
(POWER INDICATOR OFF)
CHECK J705
PIN5, PIN6 (5V)?
U501 PIN 8 VOLTAGE
CHECK KEY CONTROL
CONNECTOR ROUTINE
PIN90 (3.3V)
VOLTAGE ?
1 CHECK U201 PIN 96
CHECK U201
Waveforms
1
U201-#96

TROUBLESHOOTING GUIDE

VOLTAGE
YES
CHECK
(5V) ?
YES
IS U201
YES
PULSE
YES
1. NO POWER
NO
NO
NO
NO
- 15 -
CHECK POWER BOARD,
AND FIND OUT A SHORT
POINT AS OPENING
EACH POWER LINE
CHECK 5VS LINE
(OPEN CHECK)
NO PROBLEM
CHECK 3.3V LINE
CHECK X-TAL