Philips 170M4FS/00, Service Manual

Page: 79 / 83

79
170T4
Repair Flow Chart
Go to cover page
1.No Work / LED is
off
Check if
power switch
is normal
Replace power switch
Yes
No
Check if power
adaptor output
= 16V
(see p25)
Replace Adaptor
Check if fuse
F1 is normal
(see p42)
Replace fuse and
eliminate short or
open situation
Try to Replace
7401 CPU or
7402 CPU s EEPROM or
¢
Yes
Yes
No
No
2.No raster / Picture
too dim
Check if connector 1002
Check working
voltage, backlight
control signal and
brightness control
signal on scaler board
No
Yes
Check if inverter
output =
/ -10%
60+/-5KHz
Replace Inverter board
No
Yes
Replace LCD panel due to
backlight damage
3.No picture / LED is
green
Check if working voltage
3V3, 2V5, 5V to
7401 CPU
7402 EEPROM
see p30
Check circuit around each
regulator and eliminate short
and open situation
7252 pin11=3.3V
7981 pin44 =3.3V
7007 pin4 =5V
No
Yes
Check if clock source
1401 output 14MHz
Replace 1401
No
Check if scaler 7401
output , TT L,Hsync,
Vsync , clk, H/V and
HDTV
Try to replace
7401 CPU or
7402 CPU s EEPROM
¢
No
Yes
Yes
Check resistors-
network
3271~3277
Replace bad resistors-
network 3271~3277
No
Yes
Replace LVDS cable
No
Replace LCD panel
4.No D-sub
picture
Check if H/V
signals input to
Schmitt trigger
7203
Check input path from 1201
to 7203
No
Yes
Check if Schmitt
trigger 7203
output H/V signals
to 7401
Replace 7203
No
Go to 3. No picture / LED is green
Yes