Philips 300WN5QS/97, Service Manual

Page: 35 / 87

35 300WN5
Repair Flow Chart
Go to cover page
Check resistors-
network
3481~3486
Replace bad resistors-
network 3481~3486
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 JAGASM
Replace 7203
No
Go to 3. No picture / LED is green
Yes
3.No picture / LED is
green
Check if working voltage
3V3, 2V5, 5V to
7402 JAGASM
7753 CPU
7754 CPU’S flash ROM
7752 CPU’s EEPROM
7701 Painter
7722 Painter’s EEPROM
Check circuit around each
regulator and eliminate short
and open situation
7001 pin2=5V
7008 pin3=2V5
7009 pin2=3V3
No
Yes
Check if clock source
1401 output 14MHz
1753 output 22MHz
1702 output 12MHz
Replace 1401, 1753 or 1702
No
Check if scaler 7402
output 48 bits TTL
RGB, clk, H/V and
DE signal
Try to replace
7753 CPU or
7754 CPU’s flash ROM
7752 CPU’s EEPROM or
7701 Painter or
7722 Painter’s EEPROM
No
Yes
Yes
1.No Work / LED is
off
Check if
power switch
is normal
Replace power switch
Yes
No
Check if AC
adaptor output
= 24V on 1102
and
=16V on 1103
Replace Power board
or go to troubleshoot
power board.
Try to replace
7753 CPU or 7754 CPU’s flash ROM
7752 CPU’s EEPROM or
7701 Painter or
7722 Painter’s EEPROM
Yes
No
2.No raster / Picture
too dim
Check if 1102 on
power board
Pin 1,2,3=24V
Pin4=0~4.7V
Pin5=3.3V Check working
voltage, backlight
control signal and
brightness control
signal on scaler board
No
Yes
Check if
inverter output =
738~1001Vrms
45K~75KHz
Replace LCD panel +
Inverter PCB
No