Dell 2208WFP Service Manual page 39

Service Manual
4.Power (include IF +5Vand +3.3V) supply normal ,key function
OK,but backlight can't be turned on
No backlight
LED lamp is OK
Is there 27V Voltage on
Pin 7,8 & 13,14 of T1
Yes
Is there PWM signal on
Pin13 of U1
Yes
Is there High level voltage
on Pin16 of U1
Yes
Vsense voltage is 2.9V
No
Are there PWM signal on
pint on Pin12 of U1
Yes
Pin14 of U1 Voltage
is Low Level
Pin6&10 of U1 voltage is
high level voltage
END
Yes
No
Yes
Yes
Yes
Yes
38
No power supply to
inverter
No
Q6, Q7
fail
No
Check I/F BD
No
Check I/F BD
Lamp connector opened
No
U1 Failure
Feedback circuit failure
U1 protected
Yes
Yes
Check the cable that from I/F
BD to P/I BD is ok
o
N
Check power supply
Yes
Replace Q6, Q7
Yes
Check R21,R22,C10
Yes
Check ZD1, R1 , ZD2, R2, C12, C13