Philips PTV800, Service Manual

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CIRCUIT DESCRIPTION
PTV Introduction
The PTV800 series Projection TV Chassis was developed by Philips/Magnavox Consumer
Electronics for the 1998 model year. This Chassis is used in the 48, 52, 54, and 60 inch
screen sizes. The Tuning System is On-Screen, Remote controlled and Menu Driven. The
Tuning System is mounted on the Small Signal Board and will tune 178 channels. The
PTV800 and PTV805
(Figure 1) uses a single Tuner Tuning System which is controlled by the
I2C bus. The PTV810 and above uses a two tuner Tuning System. (Figure 2) Each Tuner has
its own Saw Filter and IF circuitry. All TV functions are controlled via the Menu except Power,
Channel Select, Personal Preference, Volume, Mute, Alternate Channel, Sleep Timer, and
Channel Guide. The Microcomputer communicates via an I2C bus with the Tuners, EEPROM
IC304, Stereo Decoder IC120, Signal Processor IC600, Digital PIP IC1001, and the AV
Switcher IC1. The I2C bus also communicates with the Gemstar panel, Digital Convergence
panel, and ESI bus panel. Sets with the ESI bus panel are equipped with an external jack to
accept control data from add on equipment. An I2C bus is a two-line communications link
between IC's consisting of a Serial Clock and Serial Data line. The Microcomputer IC300
communicates with the Signal Processor IC600 to control Brightness, Picture, Color, Tint, and
Sharpness.