DOWNLOAD Sharp LC-15B2E (serv.man2) Service Manual ↓ Size: 225.07 KB | Pages: 32 in PDF or view online for FREE

CIRCUIT

REF.No.

MAIN PARTS CODE

FUNCTION

Tuner

TU3201

VTUVT2U5CD553

PLL channel selection, Video detection, Audio detection, AFT, AGC

Audio circuit

IC3304

RH-IX3371CEN1Q

Digital audio signal processing

SIF detection, NICAM/IGR detection and decode

Audio input switching, Equalizer, Volume control

A/D converter, D/A converter

IC3301

VHINJM4560M-1

Operational amplifier

IC3302

Active filter (acoustic characteristic correction)

IC3303

IC3305

VHILA4635A+-1S

Audio output amplifier

Power supply

IC3701

VHINJM2377M-1

DC/DC PWM control

circuit

T3701

RTRNZ0800CEZZ

DC/DC transformer

IC3702

VHINJM2147M-1

Operational amplifier, 31V/29V power supply stabilization

R3760

RVR-M8026TAZZ

B+ adjusting control (+5V adjustment)

Lamp error detection

Discrete circuit

Lamp error detection

AV2-IN/OUT

IC3501

VHITC4053BF1E

Audio I/O switching

Discrete circuit

Video I/O switching

CIRCUIT

REF.No.

MAIN PARTS CODE

FUNCTION

AV1 input

Discrete circuit

Video/Audio/S video input terminal

Inverter circuit

T5701

RTRNZ0777CEZZ

LC-13B2H/M, LC-15B2H/M only

T5702

DC/AC inverter

Backlight lamp drive

CIRCUIT

REF.No.

MAIN PARTS CODE

FUNCTION

Operation circuit

Switches

Power switch, Channel selector UP/DOWN switch

Volume UP/DOWN switch, Menu switch, TV/VIDEO switch

CIRCUIT

REF.No.

MAIN PARTS CODE

FUNCTION

Remote control circuit

RMC4002 RRMCU0239CEZZ

Infrared remote control receiver

LED circuit

D4014

RH-PX0421CEZZ

Power LED (Standby: Red, Power-on: Green)

D4015

RH-PX0421CEZZ

Sleep Timer LED (Sleep Timer ON: Red)

CIRCUIT

REF.No.

MAIN PARTS CODE

FUNCTION

Inverter A

T6751

RTRNZ0798CEZZ

DC/AC inverter

T6752

Backlight lamp drive

T6753

Inverter B

T6551

RTRNZ0798CEZZ

DC/AC inverter

T6552

Backlight lamp drive

T6553

The tuner, whose RF circuit is composed of FET and whose local oscillation circuit, mixing circuit, IF amplifier
circuit and PLL circuit are composed of 1-chip IC, is 2-in-1 construction which has IF signal processing circuit
built in.
The channel selection circuit is of PLL frequency synthesizer type under the control of I2C bus. The receiving
frequency range is from 44.25 to 863.25 MHz, which can cover almost all VHF, UHF and CATV channels.
The IF signal processing circuit of the split carrier type employs the video PLL synchro system.
For video, a 1Vp-p composite signal is outputted from the terminal No. 19 (Video).  For audio, a SIF signal is
outputted from the terminal No. 15 (SIF).

21
ANT

HPF

BPF RF AMP

BPF

RF AMP

T.BPF

MIX

OSC

LPF

SAW

VIF

AMP

VIDEO

DET

FM DET AF AMP

EQ

AMP

SAW

IF AMP

MIX

I

2

C PLL

OSC

MIX-PLL IC

T.BPF

VHF SECTION

AGC

1

AS

3

SCL

4

SDA

5

MB

6

BP

7

BT

9

IF OUT

11

SIF

AMP

AGC

AFT

18

MUTE

17

SIF 
OUT   15

AUDIO
OUT   16

VIDEO
OUT   19

The audio signal processing circuit is mainly composed of a 1-chip digital audio signal processing circuit (IC3304),
an active filter circuit (IC3301-IC3303) and an audio amplifying IC (IC3305).
Controlling of IC3304 is all under microprocessor control (I

2

C bus control, port control).

The SIF signal sent from the tuner is amplified in the SIF amplifying circuit composed of Q3201 and Q3202 and
is inputted to pin (87) (ANA_IN+ terminal) of IC3304.  Then, after being A/D-converted, it is subjected to FM
detecting and sound multiplex decoding (NICAM/IGR) in digital signal processing.
The TV audio signal and the audio input signal for three systems (video: 2, component: 1) A/D-converted in
IC3304 are switched in the IC, subjected to volume controlling and equalizer correction (for acoustic character-
istic correction) and then outputted from pins (27) and (28) as analog signals after being D/A converted.
The audio signal outputted from pins (27) and (28) of IC3304 is subjected to acoustic characteristic correction in
the active filter circuit composed of IC3301, IC3302 (used in 13/15 only) and IC3303, audio-amplified in IC3305
and then outputted through J3500 (headphone jack) to the speaker.
The analog audio signal outputted from pins (36) and (37) of IC3304 is subjected to V2 audio I/O switching in
IC3501 and outputted from the AV2 terminal (AV2 terminal output mode).

AV1

S-VIDEO

INPUT

AV2

INPUT

OUTPUT

COMPONENT

INPUT

AUDIO

IN/OUT

SWITCH

IC3501

Q3500

AUDIO

DECODER

(MSP)

IC3304

L2, R2

DL, DR

L1, R1

I

2

C

AUDIO

FILTER

IC3301

IC3303

IC3302

Model

13/15

DC POWER

AUDIO

AMPLIFIER

IC3305

HEAD

PHONE

JACK

SP-L

SP-R

The video signal processing circuit is a multi video system that is mainly composed of a digital video signal
processing IC (IC801).
The TV video signal sent from the tuner and the V1 video input signal and V2 video input signal inputted through
each input terminal are switched in IC402 and inputted to pin (73) of IC801.  The Y/C signal inputted to the S
terminal is inputted to pins (71) and (72) of IC801.
The AV2 terminal is capable of I/O switching and controlled by Q3501 thru Q3505.

AV1

S-VIDEO

INPUT

V1

V2

AV2

INPUT

OUTPUT

VIDEO

SWITCH

IC402

V

SY, SC

VIDEO

IN/OUT

SWITCH

Q3501-

Q3503

V0

CVIN

CSYNC0

BUFFER

Q402

BUFFER

Q401

SYNC

SEPARATER.

IC401

MPU

IC2001

VOUT

I

2

C

3.3V REG.

VIDEO

DECODER

(VPC)
IC801

LCD

PANEL

AD-converted 
data is inputted.

Data, clock, etc. 
are inputted.

OSD data etc. is inputted.

1-3. GRAY LEVEL
CIRCUIT

1-5. LCD

CONTROLLER

CIRCUIT

RGB-converted 
data is outputted.

Gray level reference 
voltages and electrode 
signals are outputted.

The video signal or Y/C signal inputted to IC801 is AD-converted in the IC and subjected to various video
adjustments in digital signal processing.  As a Y/UV digital signal (ITU-R601 format) the Y data is outputted from
pins (31) thru (34) and (37) thru (40) and the C data (UV data) is outputted from pins (41) thru (44) and (47) thru
(50), and then they are inputted to the LCD controller circuit.

CIN

VIN1

VIN2

VIN3

VIN4

VOUT

RGB/

YCrCb

RGB/

YCrCb

FB

Analog

Front-end

AGC

2

×

ADC

Analog

Component

Front-end

4

×

ADC

Processing

Matrix

Contrast

Saturation

Brightness

Tint

Adaptive

Comb

Filter

NTSC

PAL

Color

Decoder

NTSC

PAL

SECAM

Saturation

Tint

Mixer

2D Scaler

PIP

Pehorame

Mode

Contrast

Brightness

Peaking

Output

Formatter

ITU-R656
ITU-R601

Memory

Control

Y

Cr

Cb

Y

Cr

Cb

Y/G

Y

Cr

Cb

FB

U/B

V/R

FB

Y OUT

Cr Cb
OUT

YCOE

FIFO
CNTL

LL Clock

H Sync

V Sync

AVO

I

2

C Bus

I

2

C Bus

Clock
Gen.

Sync

+

Clock

Generation

20.25MHz