Service manual

CB-6
CB CIRCUIT DESCRIPTIONS
sor from pin 49 along with the processed RGB. An exception to this occurs when Gemstar
®
is displayed.
Under that circumstance, the fast-blanking pulse without RGB is sent to the video processor via the
Gemstar
®
board.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
36
26 27
28
29
30
31
32
33
34
35
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
HSYNC
VSYNC
AFC
N/C
SD2
SD
KEY1
KEY2
AFC2
Y/C1-SENSE
Y/C2-SENSE
Y/CF-SENSE
CRT-PROT
MUTE
IR DET
N/C
N/C
AVDD
HLF
RVCO
VHOLD
CVIN
CNVSS
XIN
XOUT
VSS
R
G
B
FB
PiP-BRIGHT
N/C
N/C
N/C
AUD-SWAP
N/C
GM-RESET
YUV/SWITCH
H/T
SCL1
SCL2
SDA1
SDA2
IDENT
N/C
DEG-CTL
POWER
N/C
RESET
OSC-OUT
OSC-IN
VDD
IC6000
C6012MC6013
L6001
+5VSBM
+5VSBF
CRY6001
R6034M
C6010M C6011M
C6008M
R6080
R6033M
C6009
R6032M
C6007M
R6031M
C6006
C6005M
R6030
L6007
+5VSBF
C6037
C6044
1 2 3 4 5
L6004
R6015M
R6016M
R6027
C6003M
L6005
C6035
PROV
C6036M
R6010
C6040MC6002M
C6059M
Q6001
C6001M
R6003M
R6004
R6001M
R6002M
Q6002
Q6004
R6007M R6005M R6006M
C6026M
R6008M
+5VSBF
D6002
C6058M
R6009M
R6017M
R6014M
R6011M
+5VSB
C6004M
C6022M
C6034M
R6063
R6064
Composite Video
C6060M
R6051
+5VSBF
R6052M
C6061M
R6013
C6041M
C6042M
C6043M
R6069M
R6070M
D6003
R6012M
V-Sync
V-Ramp
Flyback
SD2
SD
AFC-Main
AFC2
CRT-Protect
Mute
Y/C1-Sense
Y/C2-Sense
Y/C-Front-Sense
2K6
EXTERNAL KEYBOARD
<<Figure CB-6>>
The CB chassis features a halftone function that dims video surrounding OSD. This halftone circuit is
described in the video section, but is controlled by a DC level from pin 40.
Closed captioning display is accomplished in the microprocessor by use of the composite video into pin 22.
Here a data slicer extracts the caption information and outputs it to the RGB pins when captioning is re-
quested by the user. Note that when OSD needs to be on the screen, such as after a channel change or
during a volume change, the OSD will have priority, and CC will mute until OSD turns off.
Pins 5 and 6 are signal detection pins. When the either of the chassis two tuners detects a bona-fide signal
to the video processor, it separates horizontal sync signal from the IF and sends it to this portion of the
microprocessor. It can then be used to determine if a certain channel is carrying a valid active broadcast.
Automatic frequency correction (AFC) is sent to the microprocessor via pin 3 and pin 9 (for the second
tuner IF). The DC level on either pin tells the microprocessor if it needs to communicate an adjustment to