Sharp C-2890EES, Service Manual

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AK - 45
CHASSIS
4.VIDEO SWITCH TEA6415
In case of three or more external sources are used, the video switch IC TEA6415 is used. The main
function of this device is to switch 8 video-input sources on the 6 outputs.
Each output can be switched on only one of each input. On each input an alignment of the lowest level
of the signal is made (bottom of sync. top for CVBS or black level for RGB signals).
Each nominal gain between any input and output is 6.5dB.For D2MAC or Chroma signal the alignment
is switched off by forcing, with an external resistor bridge, 5VDC on the input. Each input can be used
as a normal input or as a MAC or Chroma input (with external Resistor Bridge). All the switching
possibilities are changed through the BUS. Driving 75ohm load needs an external resistor. It is possible
to have the same input connected to several outputs.
5.MULTI STANDARD SOUND PROCESSOR
The MSP 34x10G family of single-chip Multi-standard Sound Processors covers the sound processing
of all analog TV-Standards worldwide, as well as the NICAM digital sound standards. The full TV sound
processing, starting with analog sound IF signal-in, down to processed analog AF-out, is performed on
a single chip.
The DBX noise reduction, or alternatively, MICRONAS Noise Reduction (MNR) is performed alignment
free.
6.SOUND OUTPUT STAGE WITH TDA7269A
The TDA7269A is class AB dual Audio power amplifier assembled in the Multi-watt package, specially
designed for high quality sound application as Hi-Fi music centers and stereo TV sets.
7.VERTICAL OUTPUT STAGE WITH STV9379FA
The IC STV9379FA is the vertical deflection booster circuit. Two supply voltages, +14V and –14V are
needed to scan the inputs VERT+ and VERT-, respectively. And a third supply voltage, +60V for the
flyback limiting is needed. The vertical deflection coil is connected in series between the output and
feedback to the input.
8.VIDEO OUTPUT AMPLIFIER TDA6108
The TDA6108Q includes three video output amplifiers is intended to drive the three cathodes of a
colour picture tube.
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MHC108
DIGITAL VCO CONTROL AFC DETECTOR RC VCO
VIF-PLL
VIF-AGC TUNER AGC
SUPPLY SIF-AGC
AUDIO PROCESSING
AND SWITCHES
NARROW-BAND
FM-PLL DEMODULATOR
SINGLE REFERENCE QSS MIXER
INTERCARRIER MIXER
AND AM DEMODULATOR
SOUND CARRIER
TRAPS
4.5 to 6.5 MHz
TAGC
CVAGC(pos)
CAGC(neg)
CBL
VAGC
(1)
TOP
14 (15)
VPLL
19 (21) 9 (8) 16 (17) 15 (16) 21 (23)
4 (2) 10 (9) 11 (10) 12 (11) 18 (20) 20 (22)
2 (31)
1 (30)
(18) 17
(7) 8
(3) 5
(4) 6
external reference signal
or 4 MHz crystal
REF AFC
AUD
CVBS
audio output
video output: 2 V (p-p)
[1.1 V (p-p) without trap]
CAF
SIOMAD SDA SCL
MAD
VP
CAGC
(6, 12, 13, 14, 17,
19, 25, 28, 29, 32)
13
n.c. AGND
7 (5)
DGND
OUTPUT
PORTS
I
2
C-BUS TRANSCEIVER
22 (24) 3 (1)
OP1 OP2 FMPLL
DEEM
AFD
sound intercarrier output
and MAD select
FM-PLL
filter
VIF-PLL
filter
de-emphasis
network
VIF2
VIF1
24 (27)
23 (26)
SIF2
SIF1
TDA9885
TDA9886
(1) Not connected for TDA9885.
Pin numbers for TDA9885HN and TDA9886HN in parenthesis.