Samsung LE 15S51B Service Manual

9 Schematic Diagrams
9-7
 

9 Schematic Diagrams9-8
 

9 Schematic Diagrams
9-9
- This Document can not be used without Samsung’s authorization.9-5 IP Board Schematic Diagram(LE20S51BP)
 

9 Schematic Diagrams9-10
 

4 Troubleshooting
4-1
4 Troubleshooting
4-1 First Checklist for Troubleshooting
1. Check the various cable connections first.
- Check to see if there is a burnt or damaged cable.
- Check to see if there is a disconnected cable connection or a connection is too loose.
- Check to see if the cables are connected according to the connection diagram.
2. Check the power input to the Video Board.
3. Check the voltage in and out between the SMPS         Video Board, between the SMPS           X, Y 
Drive Board,...

4 Troubleshooting
4-2
4-2 Checkpoints by Error Mode
4-2-1 No Power
Does proper DC 14V/5V
appear at Pin 3. Pin 9 of
CN100?Check connector Pin3, Pin9 in
I/P Board.
YesNo
No
No
No
No
Does proper DC A5V 
appear at FT144?Check IC101 and IC105.
Yes
Does proper B3.3V 
appear at Pin 2 of IC111?Check IC102.
Yes
Does proper DC B1.8V 
appear at Pin 4 of Q802,
Q803?Check Q802, Q803.
Yes
Does proper DC B8V 
appear at IC109?Check IC109.
1
2
3
4
5
No
No
No
Check IC800 and IC400.
Yes
Does proper DC 5V_P
appear 
at Pin 2...

4 Troubleshooting
4-3
WAVEFORMS
12
5
3
644
78
 

4 Troubleshooting
4-4
4-2-2 No Picture (TV, Video, S-Video, Component)
Check R882(TV)
Check C884(Video)
Check C851, C852(S-Video)
Check C511,C513,C515(Component)?
Check the input signal.
Yes
Check the IC800,IC500.
WAVEFORMS
9
9No
 

4 Troubleshooting
4-5
Does the signal appear at 
C883,C880(TV) and 
C849, C850(PC) and  
C881,C882(Component) Pin 117, 
of IC800 (VCTj)?Check the TU01 (TV Tuner)
Check the CN913 (Video, S-Video)
Check the CN901 (Component)
Check the CN909
Yes
Does the signal appear at
R858, R859?Check IC800.
Yes
Does the signal appear 
at Pin 2, 5 of Pin 16, 19
IC600?Check the IC600 (Audio amp)
and related circuit of IC600.
Yes
Replace the speaker.
4-2-3 No Sound
No
No
No
 

4 Troubleshooting
4-6
Memo