Sound Alignment; Sub-Contrast Alignment; Comb Filter Alignment; Sub-Brightness Adjustment - Philips PTV500 series Service Manual

Sound Alignment
1. Select an active channel and loosely couple the antenna
until noise/distortion is apparent in the output.
2. While keeping input signal weak enough to produce noise,
adjust the Sound Discriminator (L201) for maximum output
and minimum distortion.
Sub-Contrast Alignment (this adjustment requires the use of
equipment not normally carried into the home)
1. Apply an NTSC Color Bar Pattern Signal to the antenna ter-
minals.
2. Tune the receiver to the applied signal in step 1.
3. Connect an oscilloscope to Pin 53 of IC600. Adjust the Sub-
Contrast Control (R639) until the video signal observed on
the oscilloscope is 1Vp-p +/-10mV.
Comb Filter Alignment (this adjustment requires the use of
equipment not normally carried into the home)
Note:The following procedure covers the only Field Adjustable
Controls contained within the CCD Comb Filter Module. These
are also the only controls accessible through holes provided in
the top shield of the Module.
1. Apply a Color Bar signal from a Color Bar Generator to the
Tuner Input.
2. Connect an Oscilloscope to TP34.
3. Adjust R20 for minimum color sub-carrier as seen on the
oscilloscope.
4. Adjust R56 for minimum color sub-carrier as seen on the
oscilloscope. Repeat steps 3 and 4 for best results.
Sub-Brightness Adjustment
Note:Refer to the Gray Scale Tracking and Sub-Brightness pro-
cedure contained later in this section for the precise setting of all
interrelated controls.
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