JVC XV-1000BK, Service Manual

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[ Servo Volume 2 ]
Troubleshooting when TEST mode check was OK.
DVD During normal playback operation (TEST mode is OK)
(1) Neither picture nor sound is output
* Cannot search
a). Can the feed system be driven?
Check the waveform of control voltage W003. Line between IC301 and W003 or TP253.
* NG after DEM/ECC (IC351, etc.)
Check the waveform of CN101"1" and "2". After the driver (IC251)
For short-distance search, the waveform
becomes roundish, not trapezoidal, and
voltage is low.
b). Is kick available?
Check the control voltage waveform from TP251 (W001) From IC301 to W001
Check the waveform of CN101"22" and "23" After the driver (IC251)
Although differs in amplitude and DC offset, the waveform is similar to that of W003.
Long-distance seek
Feed
Tracking
Hold (DC) during feed
Acceleration pulse at start;
deceleration pulse at stop
(each one)
(In the direction of search,
opposite to this figure)
Kick pulse (fine seek) is
inserted after long-
distance seek.
(Not one)
Kick pulse
Search results in a change of duty
(three values with 2.5V at the center)
(The figure is exaggerated.)
Approx.
2.5V