Philips PTV800, Руководство по обслуживанию

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Signal Processor
Luminance from IC701 is fed through a delay circuit, amplified by Q601, and is buffered by
Q611 and applied to IC600 Pin 61
. (Figure 16) The output of Q601 is buffered by Q602 to
provide sync to Pin 61 of IC600. Chroma is fed to IC600 on Pin 47.
Red, Green, and Blue OSD and fast blanking from the Microcomputer and Convergence Panel
are fed to the IC on Pins 31, 30, 29, and 28 respectively. Red, Green, and Blue drive for the
CRT's are output on Pins 18, 19, and 20 respectively. The Red drive signal is buffered by
Q618 and Q604. Q619 is used for blanking and to kill drive to the tubes if the CRT protection
circuit is activated. In a similar manner, Green drive is buffered by Q616 and Q605. Q617 is
the Green blanking transistor. Blue drive on Pin 20 is fed to buffer transistor Q632 and is
amplified by Q608 and Q607 before being buffered by Q620 and Q606. Q621 provides
blanking for the Blue drive. Q632 and Q607 is a Blue Stretch circuit which provides a slight
delay and extra gain to the Blue signal.
The Luminance signal is fed into IC600 on Pin 61 to provide sync to the Vertical and Horizontal
Oscillator. A 503 KHz crystal on Pin 5 provides the reference for the count down circuit in
IC600. Horizontal drive on Pin 8 of IC600 is fed to the Large Signal Panel through Pins 2 and 5
of J601. Vertical drive is routed to the Large Signal Panel by J601 Pins 1 and 6 from IC600
Pin 62.