Circuit Overview; Chassis Overview - Zenith Presentation Series Service Manual

CHASSIS OVERVIEW

CONNECTIONS
This chassis has two means of A/V connectivity, one
jackpack in the front and one in the back. The rear
jackpack accommodates composite video, Y/C (super
video), RGB Computer, and TV RF inputs. The front
jackpack has only composite video and RGB computer
inputs.
SIGNALS
Two types of signals, NTSC and SVGA, are processed in
the set. NTSC signals enter by four inputs.
•
CV RF: The IF section sends the composite
video to the A/V switch (ICX2900) at pin 53
(VinE4).
•
CV-1: Fed from the rear jackpack to the A/V
switch at input pin 7 (VinS1).
•
CV-4: This input, called Camport, is fed to the
A/V switch via pin 5 (VinE1).
Video Circuit
CV-1
L1-IN
R1-IN
L2-IN
Rear R2-IN
Jack
Y1-IN
Pack
C1-IN
L3-IN
R3-IN
Y MON OUT
C MON OUT
VM-OUT L
VM-OUT R
C IN
Y IN
Front
Jack
Pack
C OUT
Y OUT
TV
One
Card
SR23 - 923-03509

CIRCUIT OVERVIEW

CV RF
9V
Y INS1
SCL
Y IN1
SDA
ICX2900
C INS1
BPS
221-01053
C IN1
BPF
C OUT
V OUT
COMB FILTER
RESET
R
G
B
HS
VS
CV SEN
CV IN
R
G
B
HS
VS
•
Y1-IN: This is the luminance input of the Y/C
(super video) connector and is fed to the A/V
switch through pin 15 (YinS2).
•
C1-IN: This is the Chroma part of the Y/C (super
video) connector and is fed to the A/V switch
through pin 17 (CinS2).
All of these signals must be input to the A/V switch
with a 1 Volt Peak-to-Peak (Vp-p) level. The
microprocessor selects the signal through the I
If the signal is composite video, it is sent to the comb
filter to separate the luminance and chroma components.
The luminance signal is fed back to the A/V switch at
pins 9 (YinS1) and 48 (Yin1). The chroma signal is sent
to a pair of band-pass filters, one for the composite
video inputs and one for the COMPOSITE VIDEO RF
(because the two signals have different levels). Then
the chroma is fed back to the A/V switch via pins 11
(CinS1) and 40 (Cin1).
The correct signal is selected by the microprocessor
and the A/V switch sends it to pins 44 (Yout1) and 42
(Cout1) and to ICX2201.
IC6000
221-01391-P07
F G B S S
R
B C D
L A
SDA
VS
HS
Y IN
C IN
SCL
Y OUT
ICX2200
221-01376
A V
M
K
B
R G B
Video Ouput Board
3-1
ICX2201
221-01377
Y U V H V
SDA
S S
SCL
SCP
V TIM IN
ICX2600
V OUT
221-01378
H OUT
H FBP
ABL FIL
H DR
H PROT
EW-DR
6V
H FBP
220V
FIL
V DR+
V DR-
VPROT
12V
To Large
G2
Signal Module
FOCUS
CS - SERVICING
C bus.
2
F0
ABL