Philips PTV800, Руководство по обслуживанию

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Sub-Contrast Alignment
1. Enter the Service Mode via the previous procedure (06-25-96-Menu) and apply an NTSC
Color Bar Pattern Signal to the antenna terminals.
2. Tune the receiver to the applied signal in step 1.
3. Connect an oscilloscope to Pin 20 of IC600. Adjust the Sub-Contrast Register (52) until
the video signal observed on the oscilloscope is 1Vp-p +/- 10mV.
4. Typical default value is F0H.
Sub-Brightness Adjustment
Note:
Refer to the Gray Scale Tracking, Sub-Brightness procedure later in this section for the
precise setting of all interrelated controls.
Picture Height Adjustment
1. Enter the Service Mode via the previous procedure (06-25-96-Menu) and apply a
crosshatch pattern to the antenna input terminals.
2. Adjust the Picture Height Register (37) to obtain a slight underscan of the raster at the top
and bottom of the screen.
3. Adjust the Picture Height Register (37) to obtain a slight overscan at the top and bottom
portions of the screen (approx. 8% overscan total).
4. Typical default value is F0H.