JVC AV-20D304/SA Schematics

A V-20D304 AV-20D304

AV-20D304

/SA

STANDARD CIRCUIT DIAGRAM

NOTE ON USING CIRCUIT DIAGRAMS

1.SAFETY

The components identified by the symbol and shading are
critical for safety. For continued safety replace safety critical
components only with manufac tures recommended parts.

2.SPECIFIED VOLTAGE AND WAVEFORM VALUES

The voltage and waveform values have been measured under the
follo win g c onditions.

(1)Input signal : Colour bar signal

(2)Setting positions of
each knob/button and
variable resistor

(3)Internal resistance of tester
(4)Oscilloscope sweeping time

(5)Voltage values

Since the vol tage values o f signal cir cuit vary to s ome extent
according to adjustments, use them as reference values.

: Original setting position
when shipped

:DC 20k
:H
:V

:Others

:All DC voltage values

/V

20µs/div
5ms/div

Sweeping time is
specified

3.INDICATION OF PARTS SYMBOL [EXAMPLE]

In the PW board

:R1209

R209

4.INDICATIONS ON THE CIRCUIT DIAGRAM

(1)Resistors

Resistance value
No unit :[

K
M

Rated allowable power
No indication :1/ 16 [W]
Others :As specified

Type
No indicatio n
OMR
MFR
MPR
UNFR
FR

Composition resistor 1/2 [W] is specified as 1/2S or Comp .

(2)Capacitors

Capacitance value

1 or higher :[pF]

less than 1
Withstand voltage

No indication :DC50[V]
Others :DC withstand voltage [V]
AC indicated

Electrolytic Capacitors

47/50[Example]:Capacitance value [µF]/withstand voltage[V]

]

:[k

]

:[M ]

:Carbon resistor
:Oxide me tal film res istor
:Metal film resistor
:Metal plate resistor
:Uninflammable resistor
:Fusible resistor

:[µF]

:AC withstand voltage [V]

Type

No indication

MM
PP

MPP

MF
TF
BP

TAN

(3) Co i ls

No unit
Others

(4)Power Supply

Respective voltage values are in dicated

(5) Tes t poi nt

:T est point

(6)Connecting method

(7)Ground symbol

:LIVE side ground
:ISOLATED(NEUTRAL) side ground
:EARTH ground
:DIGITAL ground

5.NOTE FOR REPAIRING SERV ICE

This mode l's p ower circu it is p artly diff erent in the GND. The
difference of the GND is shown by the LIVE : ( ) side GND and the
ISOLATED(NEUTRAL) : ( ) side GND.Therefore, care must be
taken for the following points.

(1)Do not touch the LIVE side GND or the LIVE side GND and the
ISOLATED(NEUTRAL) side GND simultaneously. If the above
caution is not respected, an electric shock may be caused.
Therefore, make sure that the power cord is surely removed from
the receptacle when, for example, the chassis is pulled out.

(2)Do not short between the LIVE side GND and ISOLATED( NEUTRAL)
side GND or never measure with a measuring apparatus measure
with a measuring apparatus ( oscilloscope, etc.) the LIVE side GND
and ISOLATED(NEUTRAL) side GND at the same time.
If the above precaution is not respected , a fuse or any parts will be broken.

Since the circuit diagram is a standard one, the circuit and
circuit constants may be subject to change for improvement
withou t any n otice.

NOTE
Due improvement in performance, some part numbers show
in th e circuit diagram may not agree wi th those indicated in
the part list.
When ordering parts, please use the numbers that appear
in th e Parts List.

:Ceramic capacitor

:M eta lized my lar cap ac i tor

:Polypropylen e capacitor
:Metalized polypropylene capacitor

:Metalized film capacitor

:Thin film capacitor
:Bipolar electrolytic capacitor
:Tantalum capacitor

µ

:[

H]

:As specified

:B1

:9V

:Only test point display

:Connector

:Receptacle

:Wrapping or soldering

:B2 (12V)

:5V

CONTENTS

SEMICONDUCTOR SHAPES ......................................................................2-2

BLOCK DIAGRAM........................................................................................2-3

CIRCUIT DIAGRAMS....................................................................................2-5

MAIN PWB CIRCUIT DIAGRAM ................................................................................................................ 2-5

PATTERN DIAGRAMS .................................................................................2-9

MAIN PWB P ATTERN................................................................................................................................ 2-9

CHANNEL CHART (US)..............................................................................2-11

CHANNEL CHART (CA)............................................................................. 2-12

SEMICONDUCTOR SHAPES

TRANSISTOR

BOTTOM VIE W

FRONT VI EW

E
C

B

ECB

BCE

(G)(D)(S)

ECB

ECB

IC

BOTTO M V IEW FRONT VIEW TOP VIEW

OUT
E
IN

IN OUTE

1 N

1 N

CHIP IC

TOP VIEW

N

N

N

1

N

1

N

TOP VIEW

CHIP TR

1

C

BE

N

No.52103

2-22-1

No.52103

BLOCK DIAGRAM

A V-20D304

A V-20D304

INPUT 1

VIDEO
AUDIO

AUDIO

OUT

COMPO-

-NENT
INPUT

INPUT 2

AUDIO

V1
L1
R1

L
R

Y

Pb
Pr

L2
R2

Y/C

Y/Pb/Pr

TU001

TUNER

IF

Y/C

V1

L1/R1

L2/R2

V3

L3/R3

VTV

IC101

IF DET

IC851

AV SW

MPX

IC651

V

Y
C

Y/C OUT

SW

L/R OUT

IC251

Y/C SEP

L/R

Y/C

RM SW

V3
L3
R3

Y

C

R/G/B

L/R

R/G/B

Q301

Q321

CRT

INPUT 3

VIDEO
AUDIO

RGB DRV

CRT SOCKET

PWB

(Within MAIN PWB)

AC IN

MAIN PWB

LF901

D901

IC901

POWER IC

IC702

MEMORY

Y/Pb/Pr

T921

SW.

TRANSF.

IC201

MICOM/V/C/DEF

B1

L/R

HP

IC602

AUDIO AMP

L , R

HV

L R

L/R

L

SP L

R

SP R

Q521

H.OUT

IC421

VERT OUT

H

V

DY01

T521

HVT

FOCUS
SCREEN

(ITC)

No.52103 No.52103

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