JVC XV525BK
Manual de Servicio

XV-521BK/523GD/525BK/421BK

(9) Neither picture nor sound is output * Cannot search a) Can the feed system be driven? Check the waveform of TRSDRV signal (R273). --- Waveform between R274 and C271.

Search results in a change of duty (three values with 2.5V at the center) (The figure is exaggerated.) Check the waveform of CN101 "1" and "2". --- After the driver (IC271)

Approx. 2.5V

For short-distance search, the waveform becomes roundish, not trapezoidal, and voltage is low.

b) Is kick available? Check the TRDRV signal waveform from R289.

Check the waveform of CN101 "22" and "23" --- After the driver (IC271) Although differs in amplitude and DC offset, the waveform is similar to that of R289

Long-distance seek Feed

Tracking

Kick pulse

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 longdistance seek. (Not one)

Hold (DC) during feed

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