B8 Color Tv Chassis Overview - Philips B8 Series Service Manual

B8 COLOR TV CHASSIS OVERVIEW

The B8 Series Chassis is the Statement (standard line) TV Set produced by Philips Consumer
Electronics Company for the 1997 model year. The B8 Chassis is used in TV Sets with 25, and
27 inch CRT's. The B8 Chassis is also used in Commercial TV Sets with 13, 19, 20, 25, and 27
inch CRT's. The chassis orientation is front to rear in the B8 design (sometimes called "North-
South"), because the chassis is longer in this direction than across. The B8 Tuning System
features 181 Channels with On-Screen Display. The main Tuning System includes the tuner
along with the Microcomputer IC and the Memory IC. The Microcomputer communicates with the
Memory IC, the Customer Keyboard, the Remote Receiver, the U/V Tuner, the TV Signal
Processor, the Stereo Decoder (optional), and the Power On/Off circuitry. The Memory IC retains
the settings for Favorite Stations, Customer Control Settings, Mode Switches, and
Service/Factory Setup Data.
The chassis features a Very Large Scale Integration (VLSI) IC for TV signal processing. This IC
performs Video IF, Sound IF, AGC control, Horizontal Signal processing, Vertical Signal
processing, Horizontal/Vertical synchronization, and Chrominance/Luminance processing. The
On-Screen Graphics information is placed on the main signal within the TV Signal Processor. On-
Screen Graphics generation and Closed Caption decoding are processed within the
Microcomputer and the signals are sent to the TV Signal Processor. Automatic Volume Level
(AVL - called "SMART SOUND" by marketing) control from the Microcomputer is sent to the AVL
IC. The "Smart Sound" function is performed within IC720.
The B8 Chassis features a Switching Mode Power Supply for the main voltage source. A "HOT"
ground reference is used in the primary side of the power supply. A "COLD" (signal) ground from
the secondary of the power supply is used throughout the rest of the chassis. AN ISOLATION
TRANSFORMER IS REQUIRED WHEN DOING SERVICE ON ANY VERSION OF THE NEW
CHASSIS.