![LG L1740B Скачать руководство пользователя страница 19](http://html.mh-extra.com/html/lg/l1740b/l1740b_service-manual_1900605019.webp)
TROUBLESHOOTING GUIDE
1. NO POWER
NO POWER
(POWER INDICATOR OFF)
CHECK KEY CONTROL
CONNECTOR ROUTINE
CHECK U201
NO
NO
NO
CHECK POWER BOARD, AND
FIND OUT A SHORT POINT
AS OPENING
EACH POWER LINE
CHECK 5VS LINE
(OPEN CHECK)
CHECK 3.3V LINE
NO
CHECK X-TAL
YES
YES
YES
YES
YES
CHECK J705 VOLTAGE
PIN5, PIN6 (5V)?
CHECK
U501 PIN 8 Voltage
(5V) ?
IS U201
PIN90 (3.3V)
VOLTAGE ?
CHECK U201 PIN 96
PULSE
1
NO PROBLEM
1
Waveforms
U201-#96