Samsung 920NW Service Manual - Page 21
Backlight can't be turned on, I/F BD to P/I BD is ok
 |
UPC - 729507800905
View all Samsung 920NW manuals
Add to My Manuals
Save this manual to your list of manuals |
Page 21 highlights
4 Troubleshooting 4-4 Backlight can't be turned on No backlight Yes LED lamp is OK Yes Is there 14V voltage on pin 3,4 of T501, T502 Yes Is there PWM signal on pin 4 of IC501 Yes Is there High level voltage on pin10 of IC501 Yes Vsense voltage 2.9V No Are there PWM signal on pin1, pin15 of IC501 Yes Pin 5 of IC501 voltage is Low level Yes Pin 3 of IC501 voltage is high level voltage No No power supply to Yes Check the cable that from inverter I/F BD to P/I BD is ok No No U501, U502 fail Check power supply No Check I/F BD Replace U501, U502 No Check I/F BD No Lamp connector opened No IC501 failure Yes Feedback circuit failure Yes Check C524,R528, R533, D507 Yes IC501 protected Yes Check D505, D511, D512, R513, R520, C520 END 4-4
-
1 -
2
-
3
-
4
-
5
-
6
-
7
-
8
-
9
-
10
-
11
-
12
-
13
-
14
-
15
-
16 -
17 -
18 -
19 -
20 -
21 -
22 -
23 -
24 -
25 -
26 -
27
-
28
-
29
-
30
-
31
-
32
-
33
-
34
-
35
-
36
-
37
-
38
-
39
-
40
-
41
-
42
-
43
-
44
-
45
-
46
-
47
-
48
-
49
-
50
-
51
-
52
-
53
-
54
-
55
-
56
-
57
-
58
-
59
-
60
-
61
-
62
-
63
 |
 |
4 Troubleshooting
4-4
4-4
Backlight can't be turned on
LED lamp is OK
No backlight
No power supply to
inverter
Check the cable that from
I/F BD to P/I BD is ok
Check power supply
Replace U501, U502
Yes
Is there 14V
voltage on pin 3,4
of T501, T502
U501, U502 fail
Yes
Yes
No
Is there PWM
signal on pin 4 of
IC501
Check I/F BD
No
Yes
Is there High level
voltage on pin10 of
IC501
Check I/F BD
No
Yes
Vsense voltage
2.9V
Lamp connector opened
No
No
Are there PWM
signal on pin1,
pin15 of IC501
IC501 failure
No
Yes
Pin 5 of IC501
voltage is Low level
Feedback circuit failure
Yes
Check C524,R528, R533,
D507
Yes
Yes
Pin 3 of IC501
voltage is high level
voltage
IC501 protected
END
Yes
Check D505, D511,
D512, R513, R520, C520
Yes
No
Yes
No