Philips PTV800, Руководство по обслуживанию

Страница: 119 / 567

Small Signal Panel
Chassis PTV810 and above are equipped with a dual tuner PIP. (Figure 13) Composite Video
output from each Tuner circuit is fed to IC1, the AV switch. The AV switch has two video
outputs. Either of the two outputs from the AV switch can select its video source from the
Tuners, Aux 1, Aux 2, SVHS1, or SVHS2. The two selected video outputs are fed to the
IC1001 Picture in Picture IC. The Output of the PIP is fed to a Comb filter where Luminance
and Chroma are separated. SVHS switch, IC701 selects Luminance and Chroma from the
Comb Filter or selected SVHS from the Video Switch. Selected Luminance and Chroma is fed
to the Chroma Luminance Processor, IC600 where On Screen Display OSD signals are added
to outgoing RGB signals. Red, Green, and Blue drive is then sent to the CRT boards. Sync is
separated from the Luminance for the Horizontal and Vertical Oscillators. Horizontal and
Vertical drive is then sent to the Large Signal Panel.
Baseband audio from the two Tuners is selected by IC105 and fed to IC120 Stereo Decoder.
Left and Right Audio is sent to IC1 AV switch. IC1 AV switch selects Audio from the Stereo
Decoder, Aux 1, Aux 2, SVHS 1, or SVHS 2. Selected Audio is fed back to the Stereo
Decoder which selects between Baseband audio or selected Left and Right audio before being
sent to the Audio Amplifier.