Sanyo VHR-M261EV Service Manual page 27

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?
YES
Is the I 2 C Bus siganl applied
to the IC301 Pins 23, 24?
YES
Does the normal RF signal
appear at the IC301 Pin 74?
YES
Does the Y(Luminance) RF
signal appear at the IC301
Pin 17?
YES
Is the Y(Luminance) Video
waveform showed up at
theIC301 Pin 41?
YES
Replace the IC301.
NO
Check the line of the 5.2V
Line. (Power Circuit)
NO
Refer to 'SYSTEM I
CHECK Trouble Shooting'.
NO
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
NO
Y(Luminance) RF signal.
(Check the Q301)
Check the path of the
NO
Y(Luminance) RF signal.
(Check Q302, Q303)
3-12
2 C BUS
NO
YES
NO
YES
NO
YES
YES
Check the System Circuit.
(IC501 Pin 24)
Check the V.H.S/W level.
(Check R304, R340)
Replace the IC301.