H_Lin. Failure; Invariable H_Size; Abnormal H_Size - Samsung 753DFX Service Manual

5 Troubleshooting

5-1-5 H_Lin. Failure

5-1-6 Invariable H_Size

IC401 Pin 28 voltage varies with
different B_DRV DAC values?
Yes
Q402 Gate output duty varies with
different B_DRV DAC values?

5-1-7 Abnormal H_Size

IC401 Pin 24 output duty
varies with different B+ offset
DAC values?
Yes
Q404 Collector
6
waveform is right?
Yes
Check Components
around D409 and L401.
5-4
Check and Replace T402
No
No
Check some parts around Q402,
No
No
Check and replace IC401.
IC401 Pin 14 ~ 16.
Check and replace IC201.
Check and replace Q405,
Q406, Q407, and Q408.
CONFIDENTIAL
WAVEFORMS
6 200 V (Q404, Collector)
CH1 P-P = 200V CH1 RMS = 387.2V
AN17K*/AN17L*