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