28LW-92H (serv.man2) - Sharp TV Service Manual (repair manual). Page 7

 

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. 
 

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. 

 

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. 
 

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.  
 

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

(1) Not connected for TDA9885.

Pin numbers for TDA9885HN and TDA9886HN in parenthesis.