Text preview for : 06_Troubleshooting.pdf part of Samsung LW20M21C Servicemanual
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5 Troubleshooting
5-1 No Power
1
Does proper DC 14V/5V appear at Pin 3. Pin 9 of CN100? Yes
No
Check CN803 Pin3, Pin9 in I/P Board.
2
Does proper DC A5V appear at FT144?
No
Check IC101 and IC105.
Yes
3
Does proper B3.3V appear at Pin 2 of IC111?
No
Check IC111.
Yes
4
Does proper DC B1.8V appear at Pin 4 of IC112?
No
Check IC112.
Yes
5
Does proper DC B8V appear at FT130?
No
Check IC109.
LW17M24C/LW20M21C
5-1
5 Troubleshooting
Yes Does proper DC 5V_P appear at Pin 2 of IC104? Yes
6
No
Check IC104.
7
Does proper DC 9V_S appear at FT127?
No
Check IC110.
Yes
8
Does proper DC B5V appear at FT131?
No
Check IC108.
Yes
Check IC704 and IC802.
5-2
LW17M24C/LW20M21C
5 Troubleshooting
WAVEFORMS
1
2
3
4
5
6
7
8
LW17M24C/LW20M21C
5-3
5 Troubleshooting
5-2 No Picture (TV, Video, S-Video, DVD)
Check C800(TV) Check C822(Video) Check C824(S-Video) Check C821(SCART)? Yes
9
No
Check the input signal.
Check the IC802.
WAVEFORMS
9
5-4
LW17M24C/LW20M21C
5 Troubleshooting
5-3 No Sound
Does the signal appear at Pin 110 (Tuner sound signal) and Pin 113, 114 (VCR sound) and Pin 119, 120 (SCART) Pin 117, 118 (PC) of IC802 (VCTj)? Yes
No
(RF) Check Tu01 (TV Tuner). (Video) Check the CN913. (SCART) Check the CN901.
Does the signal appear at Pin 123, 124 of IC802 (VCTj)?
No
Check IC802.
Yes
Does the signal appear at Pin 2, 5 of Pin 16, 19 IC600?
No
Check the IC600 (Audio amp) and related circuit of IC600.
Yes
Replace the speaker.
LW17M24C/LW20M21C
5-5
5 Troubleshooting
Memo
5-6
LW17M24C/LW20M21C