Zenith XBV323 Series, Service Manual

Page: 21 / 140

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 IC301
Pins23, 44, 45, 52, 68, 77?
Is the Y/C Bus siganl
applied to IC301 Pins53,
54, 55?
Does the normal RF signal
appear at IC301 Pin 14?
Check the line of the REG
5V Line. (Power Circuit)
Check the System Circuit.
(IC501 Pin18)
Check the V.H.S/W level.
Refer to ‘SYSTEM Y/C
BUS CHECK Trouble
Shooting’.
Is the V.H.S/W signal
applied to IC301 Pin57?
Does the Rectangular
waveform(5V) appear at
IC301 Pin57(V.H.S/W)
Clean the Drum.
Check C324.
Check R328, C322, C323.
Does the Y(Luminance)
signal appear at IC301
Pin20?
Is the Y(Luminance) Video
waveform showed up at
IC301 Pin22?
Replace IC301.
NO
YES
YES
YES
YES
YES
YES
YES
NO
NO
NO
NO
NO
NO
VCR ELECTRICAL TROUBLESHOOTING GUIDE