7 Troubleshooting
CKG7507L 7-3
Change FBT.
Check the power supply circuits.
Power indicator is green
Check Q404 and its related circuits.
Does the +B output voltage
appear at the secondary side of
T601? (45 V, 72 V, 14.7 V, etc)
Does the output
pulse appear at
Pin 18 of IC401?
Check IC501 and its application
circuits.
Does the pulse appear at
the Collector of Q503?
7-4 No Raster (1)
Yes
No
Yes
No
Yes
No
Does the DC Voltage (about 10V)
appear at Pin 7 of IC502?
Yes
Yes
Replace IC502.
No
Check HV protection circuits and
IC502’s application circuits.
No
WAVEFORMS
3
26
Does the DC Voltage
(200V over) appear at HV_ADJ
point (The condition Pin 7 of IC502
is desoldered)?
8.56 V (IC401, #18)
CH1 P-P = 8.56 V CH1 RMS = 5.900 V
3
856 V (Q503, Collector)
CH1 P-P = 856 V CH1 RMS = 251.2 V
26
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