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Rear Audio In
Front Audio In L/R Audio
IF L/R 2 Compress
Tuner Sound/Pix IF 2 IA001
ANT II60
Stereo Demux L/R
Dat WB & Tone/Vol Ext Spkr
I2C2 Audio IA002 2
Clk Amp IA502
Rear
Video Video SysCon 2 L/R
Video 2 IG401
Y Input Clk Dat
To Ext
C Switch I2C2
L/R Spkrs
IV02 Video/ R
Y/C 2 To L/R
Deflection Int Spkr To Int
Front G CRT
Vid CC Processing Amp IA003 2 Spkrs
Vid RGB IV01 B
IR In OSD 3 L/R To
2 Head
To Phones
V-Out Vert Ouput
Gemstar Dat Vert
SysCon I2C2 IF01
Yoke
m C IG401 Clk H-Out
Raw B+
Horz Ouput Run
Dat 2 TL02 Supplies
Dat Clk I C2
Clk
I2C1
EEPROM Horz
Audio Mute Yoke IHVT
IR01 Bus Exp
AC Degauss Stdby Power LL05
IR501
VC Supply TP20
Keyboard
120VAC
TX809 Simplified Block Diagram
TX809 Chassis Overview
The TX809 is a conventional NTSC analog color television chassis that
incorporates many of the latest video features. The TX809 has both front and
rear composite video (CV) and audio inputs. The chassis also features a rear
Y/C (S-Video) input that provides maximum quality video reproduction. The
Sound/Pix IF IC (II60) provides the composite video signal. The video/deflection
processing IC (IV01) is responsible for final processing of the video signal. The
RGB OSD (on-screen-display) is also input to IV01 and overlaid onto the video
signal. IV01 also provides contrast, brightness, tint and color controls.
The TX809 system control microcomputer IG401 is located in the Gemstar
module and controls and monitors the operation of the instrument via two (2) I2C
buss. The I2C1 bus reads and writes operational data (customer and factory
settings, etc.) to and from the EEPROM, IR01. The second bus (I2C2) provides
control to all other areas of the chassis. The system control micro also monitors
the keyboard and decodes the IR input from the remote control. The I2C2 bus is
also applied to the bus expander IR501 where additional control signals for the
chassis is generated.
The Sound/Pix IF IC (II60) provides the wide band audio signal. The audio circuit
consists of four (4) major IC's, they are the stereo Decoder/Demultiplexor IC
(IA002), an internal and external power amplifer IC's (IA502 / IA003) and the
audio compressor (IA001). The Audio Compressor generates a control signal
that is fed back to the system control micro to limit severe and sudden unwanted
audio level changes.
Rear Audio In
Front Audio In L/R Audio
IF L/R 2 Compress
Tuner Sound/Pix IF 2 IA001
ANT II60
Stereo Demux L/R
Dat WB & Tone/Vol Ext Spkr
I2C2 Audio IA002 2
Clk Amp IA502
Rear
Video Video SysCon 2 L/R
Video 2 IG401
Y Input Clk Dat
To Ext
C Switch I2C2
L/R Spkrs
IV02 Video/ R
Y/C 2 To L/R To Int
Deflection Int Spkr
Front G CRT
Vid CC Processing Amp IA003 2 Spkrs
Vid RGB IV01 B
IR In OSD 3 L/R To
2 Head
To Phones
V-Out Vert Ouput
Gemstar Dat Vert
SysCon I2C2 IF01
Yoke
m C IG401 Clk H-Out
Raw B+
Horz Ouput Run
Dat 2 TL02 Supplies
Dat Clk I C2
Clk
I2C1
EEPROM Horz
Audio Mute Yoke IHVT
IR01 Bus Exp
AC Degauss Stdby Power LL05
IR501
VC Supply TP20
Keyboard
120VAC
TX809 Simplified Block Diagram
The standby power supply is a conventional switch mode power supply. The
standby supply is on whenever the instrument is plugged into 120VAC. The run
supplies are only on when the set is running and are generated via a
conventional horizontal scan-derived configuration. The voltages developed by
both the standby and run supplies can vary depending upon the model and it's
features. The video/deflection processing IC (IV01) also generates both the
horizontal and vertical drive signals that are applied to the vertical and horizontal
drive circuits.