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7-6 No Video
Power indicator is green
and High voltage is appeared.
Yes
Does DC 6.3 V appear at
Pin 10 of SK1 on the
Video Socket Board?
Yes
Does DC 10 V appear at
Pin 7 of IC502?
No
Does the video input signal
appear at Pins 5, 8 and 11 of IC101
30
on the Video PCB Board?
Yes
Does the video output signal
appear at Pins 18, 20 and 23 of
31
IC101 on the Video PCB Board?
Yes
Does the video amplified pulse
appear at Pins 1, 3 and 5 of
34
IC102 on the Video PCB Board?
Yes
Check the CN105.
WAVEFORMS
30
860 mV (IC101, #5, 8, 11)
CH1 P-P = 860 mV CH1 RMS = 2.412 V
CKG7507L
No
Check the 6.3 V line at power supply
circuits (Q605, D620 and Q606).
Yes
Check the High voltage protection
circuits (IC502, L502 and D524).
No
Check signal cable and signal source.
No
Does the clamp pulse at Pin
33
Does the contrast DC 2~3 V
appear at Pin 13 of IC101?
No
Does DC 70 V appear at
31
3.28 V (IC101, #18,20,23)
CH1 P-P = 3.28 V
CH1 RMS = 2.748 V
15 of IC101?
Pin 6 of IC102?
Yes
Replace the IC102.
33
5.40 V (IC101, #15)
CH1 P-P = 5.40 V
CH1 RMS = 4.870 V
7 Troubleshooting
No
Check IC201 (Pin 37)
on the Main PCB.
Check contrast circuis
No
on the Control PCB and
Main PCB. (VR702,
Q513, etc)
34
40.8 V (IC102, #1, 3, 5)
CH1 P-P = 40.8 V
CH1 RMS = 46.28 V
7-5
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