3-12
3. Y/C CIRCUIT
(2) When the Y(Luminance) signal doesn’t appear on the screen in PB Mode,
Is 5V applied to the IC301
Pins 16, 40, 55, 58, 87?
Is the I
2
C Bus siganl applied
to the IC301 Pins 23, 24?
Does the normal RF signal
appear at the IC301 Pin 74?
Check the line of the 5.2V
Line. (Power Circuit)
Check the System Circuit.
(IC501 Pin 24)
Check the V.H.S/W level.
(Check R304, R340)
Replace the IC301.
Refer to ‘SYSTEM I
2
C BUS
CHECK Trouble Shooting’.
Is the V.H.S/W signal
applied to the IC301 Pin 11 ?
Is V.H.S/W “H” about 3.4V
at the IC301 Pin 11?
Clean the Drum.
Check the path of the
Y(Luminance) RF signal.
(Check Q302, Q303)
Check the path of the
Y(Luminance) RF signal.
(Check the Q301)
Does the Y(Luminance) RF
signal appear at the IC301
Pin 17?
Is the Y(Luminance) Video
waveform showed up at
theIC301 Pin 41?
Replace the IC301.
NO
YES
YES
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
NO
