Samsung SyncMaster CSH7839L Service Manual page 29

7-1-3 H_Deflection Failure
IC401 Pin 6 waveform is right?
3
Yes
Q405 source waveform
4
is right?
Yes
Q406 gate, drain
5 6
waveforms are right?
Yes
Q407 base, collector
7
8
waveforms are right?
No
IC251 Pin 4 is high?
Yes
Check some parts around Q252.
IC251 Pin 26 waveform
9
is right?
Yes
Check some parts around
Q253 and Q254.
CSH7839L/CSH9839L
1. Check R401, +12 V line.
No
2. Check IC401 Pins 7~6, 6~5.
3. Replace IC401.
No
Check Q405, R422, R423, R416
and D415, +220 V line.
No
Check R426, Q406.
Check +24 V line.
No
Check and replace Q407 and D412.
Check DY connector connection.
No
Replace IC251.
No
Check some parts around IC251.
3
CH1 P-P = 3.42 V
4
CH1 P-P = 3.16 V
5
CH1 P-P = 12.08 V
6
CH1 P-P = 2.20 V
7
CH1 P-P = 10.96 V
9 29.8 V (T402, #8) 8
CH1 P-P = 29.8 V CH1 RMS = 7.14 V CH1 P-P = 230 V
7 Troubleshooting
WAVEFORMS
3.42 V (IC201, #33)
CH1 RMS = 2.500 V
3.16 V (IC201, #32)
CH1 RMS = 2.560 V
12.08 V (Q253, Base)
CH1 RMS = 7.396 V
2.20 V (IC251, #15)
CH1 RMS = 2.776 V
10.96 V (IC401, #6)
CH1 RMS = 6.180 V
230 V (Q405, S
CH1 RMS = 150.1 V
7-3