HITACHI DVP2E
Manual de Servicio

1.2.5 Disc Determination
Determination is achieved by checking the sine wave by sweeping the lens with the OE IC gain at L and the FSC error amplifier (SGC) at the default setting. If no sine wave is detected, checking is retried after switching the OE IC gain to H and increasing the gain of the FSC error amplifier (SGC). If no sine wave is detected again, it is regarded as the NO DISC condition. If one half of the sine wave detected at the first lens sweep is of a value less than 0.5 V, the OE IC gain is set to H and the peak-topeak value of the sine wave is roughly adjusted to 1.8 Vp-p. By sweeping the lens around the height where the sine wave has been detected, disc determination is performed, and the sine wave is finely adjusted to 1.8 Vp-p.
Offset compensation

Lens sweep

Checking the sine wave None OEIC gain = H FCS AMP gain up

Yes

Level check

Less than 0.5V

More than 0.5V

Lens sweep

OEIC gain = H

Checking the sine wave None NO DISC

Yes

Roughly adjust to 1.8Vp-p sine wave

Disc determination

Finely adjust to 1.8Vp-p sine wave END

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