Samsung SyncMaster 753DF Service Manual page 23

5-1-3 H_Deflection Failure
Does PWM output signal appear
3
at Pin 6 (H_out) of IC401?
Yes
Does Horizontal paluse signal
4
appear at at Pin 8 of IC401?
Yes
Does 110 Vp-p signal appear
5
at Collector of Q403?
No
Check Q402, Q404, T401.
5-1-4 S Correction Failure
Check S1 ~ S4 signal.
S1~S4 signals are right at each
frequency block?
Yes
Check and replace Q404, Q409, Q410,
Q411, Q414, Q415, Q416, Q420, Q421.
SyncMaster 753DF/755DF
No
Does DC 12V appear at
Pin 10 of IC401?
Check IC401.
No
Check IC401.
No
Check Q403.
No
Check and replace IC201.
No
Yes
5 Troubleshooting
Check 12 V line.
WAVEFORMS
2.00 V (IC401, #6)
3
CH1 P-P = 2.00V CH1 RMS = 5.868V
1.00V (IC401, #8)
4
CH1 P-P = 1.00V CH1 RMS = 1.298V
5 20.0 V (Q403, Collector)
CH1 P-P = 20.0 V CH1 RMS = 46.80V
5-3