JVC AV-20RM4, AV-21RM4 Schematic

SERVICE MANUAL

COLOUR TELEVISION

YA08020052

AV-20RM4SE,
AV-21RM4SE,
AV-21RM4SN,
AV-21RM4SP

RM-C1100 TV

[AV-21RM4]

TABLE OF CONTENTS

1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-5

3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-11

5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-19

COPYRIGHT © 2005 Victor Company of Japan, Limited

No.YA080

2005/2

SPECIFICATION

Item

Dimensions ( W × H × D )

Mass 18kg 21kg

TV RF System B/G, L B/G, D/K B/G

Colour Sys­tem

Sound System A2 / NICAM

Teletext System TOP / WST

Receiving
Frequency

Intermediate
Frequency

Colour Sub
Carrier
Frequency

Power Input AC220V - AC240V, 50Hz

Power Consumption

Aerial Input Terminal 75Ω unbalanced, coaxial

Picture Tube Size Visible size : 48cm (20"),

High Voltage

Speaker 5.7cm × 12.6cm, Oval type × 2

Audio Output 5.5W (10%THD)

EXT-1 Input / Output 21-pin Euro connector (SCRAT socket) × 1

EXT-2 Input Video

Headphone Jack Mono mini jack 3.5mm × 1
Remote Control Unit VE-30017763 (RM-C1100), (AA/R06 dry battery × 2)

Design & specifications are subject to change without notice.

TV Mode PAL / SECAM PAL

Video Mode PAL / SECAM / NTSC 3.58 / NTSC 4.43

VHF(VL)

VHF(VH)

UHF

CATV

VIF
SIF

PAL

SECAM

NTSC

Audio(L/R)

AV-20RM4SE AV-21RM4SE AV-21RM4SP AV-21RM4SN

60.6cm × 47.5cm × 49.0cm

46.25MHz - 168.25MHz

175.25MHz - 463.25MHz

471.25MHz - 863.25MHz
S01 - S41 / S75 - S79 (B/G), S01 - S20 / S75 - S77(L)

38.9MHz

33.4MHz (5.5MHz:B/G)

32.4MHz (6.5MHz:L)

4.43MHz

4.40625MHz / 4.25MHz

3.58MHz / 4.43MHz

85W (Max) / 4W (Standby)

Measured diagonally

(H:41.2cm × V:31.2cm)

26kV (in cut-off service mode)

1V(p-p) 75Ω, RCA pin jack × 1
500mV(rms) (-4dBs), High Impedance, RCA pin jack × 2

60.6cm × 47.5cm × 47.0cm

85W (Max) / 3W (Standby)

Visible size : 51cm (21"), Measured diagonally

(H:41.6cm × V:31.5cm)

28kV (in cut-off service mode)

Content

PAL / NTSC 3.58 / NTSC 4.43

1-2 (No.YA080)

SECTION 1

PRECAUTION

1.1 SAFETY PRECAUTIONS [EXCEPT FOR UK]

(1) The design of this product contains special hardware,

many circuits and components specially for safety
purposes. For continued protection, no changes should be
made to the original design unless authorized in writing by
the manufacturer. Replacement parts must be identical to
those used in the original circuits. Service should be
performed by qualified personnel only.

(2) Alterations of the design or circuitry of the products should

not be made. Any design alterations or additions will void
the manufacturer's warranty and will further relieve the
manufacturer of responsibility for personal injury or
property damage resulting therefrom.

(3) Many electrical and mechanical parts in the products have

special safety-related characteristics. These
characteristics are often not evident from visual inspection
nor can the protection afforded by them necessarily be
obtained by using replacement components rated for
higher voltage, wattage, etc. Replacement parts which
have these special safety characteristics are identified in
the parts list of Service manual. Electrical components

having such features are identified by shading on the
schematics and by ( ) on the parts list in Service
manual. The use of a substitute replacement which does

not have the same safety characteristics as the
recommended replacement part shown in the parts list of
Service manual may cause shock, fire, or other hazards.

(4) Don't short between the LIVE side ground and

ISOLATED (NEUTRAL) side ground or EARTH side
ground when repairing.

Some model's power circuit is partly different in the GND.
The difference of the GND is shown by the LIVE : ( ) side
GND, the ISOLATED (NEUTRAL) : ( ) side GND and
EARTH : ( ) side GND.
Don't short between the LIVE side GND and ISOLATED
(NEUTRAL) side GND or EARTH side GND and never
measure the LIVE side GND and ISOLATED (NEUTRAL)
side GND or EARTH side GND at the same time with a
measuring apparatus (oscilloscope etc.). If above note will
not be kept, a fuse or any parts will be broken.

(5) If any repair has been made to the chassis, it is

recommended that the B1 setting should be checked or
adjusted (See B1 POWER SUPPLY check).

(6) The high voltage applied to the picture tube must conform

with that specified in Service manual. Excessive high
voltage can cause an increase in X-Ray emission, arcing
and possible component damage, therefore operation
under excessive high voltage conditions should be kept to
a minimum, or should be prevented. If severe arcing
occurs, remove the AC power immediately and determine
the cause by visual inspection (incorrect installation,
cracked or melted high voltage harness, poor soldering,
etc.). To maintain the proper minimum level of soft X-Ray
emission, components in the high voltage circuitry
including the picture tube must be the exact replacements
or alternatives approved by the manufacturer of the
complete product.

(7) Do not check high voltage by drawing an arc. Use a high

voltage meter or a high voltage probe with a VTVM.
Discharge the picture tube before attempting meter
connection, by connecting a clip lead to the ground frame

and connecting the other end of the lead through a 10kΩ

2W resistor to the anode button.

(8) When service is required, observe the original lead dress.

Extra precaution should be given to assure correct lead
dress in the high voltage circuit area. Where a short circuit
has occurred, those components that indicate evidence of
overheating should be replaced. Always use the
manufacturer's replacement components.

(9) Isolation Check (Safety for Electrical Shock Hazard)

After re-assembling the product, always perform an
isolation check on the exposed metal parts of the cabinet
(antenna terminals, video/audio input and output terminals,
Control knobs, metal cabinet, screw heads, earphone jack,
control shafts, etc.) to be sure the product is safe to operate
without danger of electrical shock.

a) Dielectric Strength Test

The isolation between the AC primary circuit and all metal
parts exposed to the user, particularly any exposed metal
part having a return path to the chassis should withstand a
voltage of 3000V AC (r.m.s.) for a period of one second. (.
. . . Withstand a voltage of 1100V AC (r.m.s.) to an
appliance rated up to 120V, and 3000V AC (r.m.s.) to an
appliance rated 200V or more, for a period of one second.)
This method of test requires a test equipment not generally
found in the service trade.

b) Leakage Current Check

Plug the AC line cord directly into the AC outlet (do not use
a line isolation transformer during this check.). Using a
"Leakage Current Tester", measure the leakage current
from each exposed metal part of the cabinet, particularly
any exposed metal part having a return path to the chassis,
to a known good earth ground (water pipe, etc.). Any
leakage current must not exceed 0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.2mA AC
(r.m.s.).

Alternate Check Method

Plug the AC line cord directly into the AC outlet (do not
use a line isolation transformer during this check.). Use

an AC voltmeter having 1000Ω per volt or more
sensitivity in the following manner. Connect a 1500Ω
10W resistor paralleled by a 0.15µF AC-type capacitor

between an exposed metal part and a known good earth
ground (water pipe, etc.). Measure the AC voltage
across the resistor with the AC voltmeter. Move the
resistor connection to each exposed metal part,
particularly any exposed metal part having a return path
to the chassis, and measure the AC voltage across the
resistor. Now, reverse the plug in the AC outlet and
repeat each measurement. Any voltage measured must
not exceed 0.75V AC (r.m.s.). This corresponds to

0.5mA AC (r.m.s.).
However, in tropical area, this must not exceed 0.3V AC
(r.m.s.). This corresponds to 0.2mA AC (r.m.s.).

AC VOLTMETER
(HAVING 1000 /V,
OR MORE SENSITIVITY)

0.15 F AC-TYPE

PLACE THIS PROBE

1500 10W

GOOD EARTH GROUND

ON EACH EXPOSED
ME TAL PAR T

(No.YA080)1-3

1.2 SAFETY PRECAUTIONS [FOR UK]

(1) The design of this product contains special hardware and many circuits and components specially for safety purposes. For

continued protection, no changes should be made to the original design unless authorized in writing by the manufacturer.
Replacement parts must be identical to those used in the original circuits. Service should be performed by qualified personnel
only.

(2) Alterations of the design or circuitry of the product should not be made. Any design alterations or additions will void the

manufacturer's warranty and will further relieve the manufacturer of responsibility for personal injury or property damage
resulting therefrom.

(3) Many electrical and mechanical parts in the product have special safety-related characteristics. These characteristics are often

not evident from visual inspection nor can the protection afforded by them necessary be obtained by using replacement
components rated for higher voltage, wattage, etc. Replacement parts which have these special safety characteristics are
identified in the Parts List of Service Manual. Electrical components having such features are identified by shading on the
schematics and by ( ) on the Parts List in the Service Manual. The use of a substitute replacement which does not have the
same safety characteristics as the recommended replacement part shown in the Parts List of Service Manual may cause shock,
fire, or other hazards.

(4) The leads in the products are routed and dressed with ties, clamps, tubing’s, barriers and the like to be separated from live parts,

high temperature parts, moving parts and / or sharp edges for the prevention of electric shock and fire hazard. When service is
required, the original lead routing and dress should be observed, and it should be confirmed that they have been returned to
normal, after re-assembling.

WARNING

(1) The equipment has been designed and manufactured to meet international safety standards.
(2) It is the legal responsibility of the repairer to ensure that these safety standards are maintained.
(3) Repairs must be made in accordance with the relevant safety standards.
(4) It is essential that safety critical components are replaced by approved parts.
(5) If mains voltage selector is provided, check setting for local voltage.

1-4 (No.YA080)

SECTION 2

SPECIFIC SERVICE INSTRUCTIONS

2.1 FEATURES

• It is a remote controlled color television.

• It can tune cable channels.

• Controlling the TV is very easy by its menu driven system.

• It has 1 Euroconnector sockets for external device.

• Front AV Input available.

• Simple teletext (Toptext, WST) system.

• It is possible to connect headphone.

• Direct channel access.

2.2 MAIN DIFFERENCE LIST

Item AV-20RM4SE AV-21RM4SE AV-21RM4SN AV-21RM4SP

MAIN PWB ASSY VE-20161051 VE-20161048 VE-20161045 VE-20161041

TV RF System B/G,D/K ← B/G B/G, L
Colour System (TV mode) PAL, SECAM ← PAL PAL, SECAM
TV RF System B/G,D/K ← B/G B/G, L

2.3 21-PIN EURO CONNECTOR (SCART) : EXT-1

Pin No. Signal designation Matching value EXT-1

1 AUDIO R output 500mV(rms) (Nominal), Low impedance Used (TV OUT)
2 AUDIO R input 500mV(rms) (Nominal), High impedance Used (R1)
3 AUDIO L output 500mV(rms) (Nominal), Low impedance Used (TV OUT)
4 AUDIO GND --- Used
5 GND (B) --- Used
6 AUDIO L input 500mV(rms) (Nominal), High impedance Used (L1)
7 B input 700mV
8 FUNCTION SW (SLOW SW) Low : 0V-3V

High : 8V-12V, High impedance

9 GND (G) --- Used

10 SCL / T-V LINK --- Not used

11 G input 700mV(B-W), 75 Ω Used

12 SDA3 --- Not used
13 GND (R) --- Used
14 GND (YS) --- Used
15 R / C input R : 700mV

C : 300mV

16 Ys input (FAST SW) Low : 0V-0.4V, 75 Ω

High : 1V-3V, 75 Ω

17 GND (VIDEO output) --- Used
18 GND (VIDEO input) --- Used
19 VIDEO output 1V
20 VIDEO / Y input 1V
21 COMMON GND --- Used

(P-P)

(P-P)

, 75 Ω Used

(B-W)

, 75 Ω

(B-W)

, 75 Ω

(P-P)

(Negative sync),75 Ω Used (TV OUT)
(Negative sync), 75 Ω Used

(P-P= Peak to Peak, B-W= Blanking to white peak)

• APS (Automatic Programming System).

• All programs can be named.

• Forward or backward automatic tuning.

• Sleep timer.

• Child Lock.

• Automatic sound mute when no transmission.

• 5 minutes after the broadcasting (closedown), the TV switches
itself automatically to stand-by mode.

Used

Used (R)

Used

Pin assignment

20 18 16 14 12 10 8 6 4 2

21 19 17 15 13 11 9 7 5 3 1

(No.YA080)1-5

SECTION 3

DISASSEMBLY

3.1 DISASSEMBLY PROCEDURE

3.1.1 REMOVING THE REAR COVER

(1) Unplug the power cord.
(2) Remove the 6 screws [A].
(3) Withdraw the REAR COVER toward you.

3.1.2 REMOVING THE MAIN PWB

• Remove the REAR COVER.
(1) Slightly raise the both sides of the MAIN PWB by hand and

withdraw the MAIN PWB backward.
(If necessary, take off the wire clamp, connectors etc.)

3.1.3 REMOVING THE SPEAKER

• Remove the REAR COVER.
(1) Remove the 4 screws [B].
(2) Remove the speaker toward you.

3.1.4 REMOVING THE FRONT AV JACK PWB

• Remove the REAR COVER.

• Remove the MAIN PWB.
(1) Remove the 2 screws [C].
(2) Remove the FRONT AV JACK PWB.

3.1.6 CHECKING THE PW BOARD

• To check the back side of the PW Board.
(1) Pull out the PW Board. (Refer to REMOVING THE MAIN

PWB).

(2) Erect the PW Board vertically so that you can easily check

the back side of the PWB.

CAUTION:

• When erecting the PW Board, be careful so that there will be

no contacting with other PW Board.

• Before turning on power, make sure that the wire connector

is properly connected.

• When conducting a check with power supplied, be sure to

confirm that the CRT EARTH WIRE (BRAIDED ASS'Y) is
connected to the CRT SOCKET PWB.

3.1.7 WIRE CLAMPING AND CABLE TYING

(1) Be sure to clamp the wire.
(2) Never remove the cable tie used for tying the wires

together.
Should it be inadvertently removed, be sure to tie the wires
with a new cable tie.

3.1.5 REMOVING THE HEADPHONE JACK PWB

• Remove the REAR COVER.

• Remove the MAIN PWB.
(1) Remove the 1 screw [D].
(2) Remove the HEADPHONE JACK PWB.

1-6 (No.YA080)

BACK COVER

A

(x6)

FRONT CABINET

SPEAKER

B

(x4)

FUNCTION

BUTTON

FRONT AV JACK PWB

D

(x1)

HEADPHONE JACK
PWB

PICTURE TUBE

CRT SOCKET PWB
(Within MAIN PWB)

C

(x2)

MAIN PWB

(No.YA080)1-7

3.2 REPLACEMENT OF MEMORY IC

3.2.1 MEMORY IC

This model use a memory IC. This memory IC stores data for proper operation of the video and deflection circuits.
When replacing, be sure to use an IC containing this (initial value) data.

3.2.2 PROCEDURE FOR REPLACING MEMORY IC SERVICE MENU

PROCEDURE

1. Power off

Switch the power off and unplug the power cord from the outlet

2. Replace IC.

Be sure to use memory IC written with the initial data values.

3. Power on

Plug the power cord into the outlet and switch the power on.

4. SERVICE MENU setting

JVCAK30/37 B20

OSD
IF1
IF2
IF3
IF4
AGC
VLIN

RGBH
VSOF

VPOF

: 1 1 AVL

(1) Press [MENU] key and, while the displayed MENU screen,

press [4], [7], [2], [5] key on the remote control unit or press
[MUTING] key and [INFORMATION] key at the
simultaneously.

Fig.1

(2) The SERVICE MENU screen of Fig. 1 will be displayed.
(3) Verify what to set in the SERVICE MENU, and set

whatever is necessary (Fig.1). Refer to the SERVICE

SERVICE MENU SELECT KEY

ADJUSTMENT for setting.

(4) Press the [STANDARD] key to exit SERVICE MENU.

5. Receive channel setting

Refer to the OPERATING INSTRUCTIONS (USER'S GUIDE)
and set the receive channels (Channels Preset) as described.

MUTING

6. User settings

Check the user setting items according to after page.
Where these do not agree, refer to the OPERATING
INSTRUCTIONS (USER'S GUIDE) and set the items as
described.

INFORMATION

AV

POWER

NUMBER

STANDARD

COLOUR

MENU

1-8 (No.YA080)

ITEM
SELECT ( )

ITEM
SELECT ( )

Fig.2

VAL UE
SELECT (+)

VAL UE
SELECT (-)

3.3 SETTING OF THE LAST MEMORY FOR SHIPMENT

3.3.1 USER SETTING VALUES

Setting item Setting value Setting item Setting value

PICTURE MENU INSTALL

BRIGHTNESS

CONTRAST BAND

COLOUR CHANNEL

SHARPNESS SEARCH

HUE(only NTSC) FINE TUNING

MODE AUTO STORE

SOUND MENU FEATURE MENU

BALANCE Center SLEEP TIMER OFF

BASS Center CHILD LOCK OFF

TREBLE Center LANGUAGE ENGLISH

MODE MONO AV-1 OUTPUT TV

EFFECT OFF

3.3.2 SETTING APS BIT IN SERVICE MENU

(1) Press the [INFORMATION] and [MUTING] keys enter service menu in TV mode simultaneously. Service Menu will appear.
(2) Press the []/[] key to select TX1(TELETEXT OPTION).
(3) Press the [7] key to set APS bit. (After this, bit 7 of TX1 will be "1")
(4) Press [STANDARD] key to exit service mode.

NOTE : DO NOT TURN OFF THE TV BY USING POWER BUTTON ON THE FRONT PANEL.

These adjust are automatically
restored when APS bit in
service menu is set.
The procedure for setting APS
bit is described below.

PROGRAMME

Refer to the INSTRUCTION

BOOK

(No.YA080)1-9

3.4 REPLACEMENT OF CHIP COMPONENT

3.4.1 CAUTIONS

(1) Avoid heating for more than 3 seconds.
(2) Do not rub the electrodes and the resist parts of the pattern.
(3) When removing a chip part, melt the solder adequately.
(4) Do not reuse a chip part after removing it.

3.4.2 SOLDERING IRON

(1) Use a high insulation soldering iron with a thin pointed end of it.
(2) A 30w soldering iron is recommended for easily removing parts.

3.4.3 REPLACEMENT STEPS

1. How to remove Chip parts

2. How to install Chip parts

[Resistors, capacitors, etc.]

(1) As shown in the figure, push the part with tweezers and

alternately melt the solder at each end.

(2) Shift with the tweezers and remove the chip part.

[Transistors, diodes, variable resistors, etc.]

(1) Apply extra solder to each lead.

SOLDER

SOLDER

[Resistors, capacitors, etc.]

(1) Apply solder to the pattern as indicated in the figure.

(2) Grasp the chip part with tweezers and place it on the

solder. Then heat and melt the solder at both ends of the
chip part.

[Transistors, diodes, variable resistors, etc.]

(1) Apply solder to the pattern as indicated in the figure.
(2) Grasp the chip part with tweezers and place it on the

solder.

(3) First solder lead A as indicated in the figure.

(2) As shown in the figure, push the part with tweezers and

alternately melt the solder at each lead. Shift and remove
the chip part.

NOTE :

After removing the part, remove remaining solder from the
pattern.

1-10 (No.YA080)

A

B

C

(4) Then solder leads B and C.

A

B

C

SECTION 4

ADJUSTMENT

4.1 ADJUSTMENT PREPARATION

(1) You can make the necessary adjustments for this unit with

either the Remote Control Unit or with the adjustment tools
and parts as given below.

(2) Adjustment with the Remote Control Unit is made on the

basis of the initial setting values, however, the new setting
values which set the screen to its optimum condition may

differ from the initial settings.
(3) Make sure that AC power is turned on correctly.
(4) Turn on the power for set and test equipment before use,

and start the adjustment procedures after waiting at least

30 minutes.
(5) Unless otherwise specified, prepare the most suitable

reception or input signal for adjustment.
(6) Never touch any adjustment parts which are not specified

in the list for this adjustment - variable resistors,

transformers, condensers, etc.
(7) Presetting before adjustment.

Unless otherwise specified in the adjustment instructions,

preset the following functions with the remote control unit:

4.4 ADJUSTMENT LOCATIONS

Setting item Setting value

BRIGHTNESS

CONTRAST

COLOUR

Center

SHARPNESS

4.2 ADJUSTMENT EQUIPMENT

(1) DC voltmeter (or digital voltmeter)
(2) Signal generator (Pattern generator)

: [PAL / SECAM / NTSC]

(3) Remote control unit

4.3 ADJUSTMENT ITEM

• FOCUS ADJUSTMENT

• SCREEN ADJUSTMENT

• OSD HORIZONTAL POSITION ADJUSTMENT

• IF ADJUSTMENT

• AGC AUTOMATICALLY ADJUSTMENT

• DEFLECTION ADJUSTMENT

• WHITE BALANCE ADJUSTMENT

TOP

FRONT AV JACK PWB

TOP

HP

HEADPHONE JACK PWB

IC500
EEP ROM

IC501
MICOM

TUNER

LED

REMOCON
RECEIVER

MENU

AV-1(SCART)

FRONT

CH. / PROG.

PL602

(+) (-)(+) (-)

VOL.

MAIN

SW

FUSE

FBT

MAIN PWB

UPPER:FOCOUS
LOWER:SCREEN

(No.YA080)1-11

4.5 BASIC OPERATION OF SERVICE MODE

4.5.1 HOW TO ENTER SERVICE MODE

(1) Press the MENU key.
(2) MENU screen will be displayed (fig.1).

MENU SCREEN

MENU

SOUND
PICTURE
FEATURE
INSTALL.
PROGRAM.

Fig.1

(3) While the MENU screen is displayed , press the [4], [7], [2],

[5] key or [INFORMATION] key and [MUTING] key
simultaneously.

(4) The SERVICE MENU screen will be displayed (fig.2).

SERVICE MENU

4.5.4 HOW TO ENTER THE GEOMETRY MENU

• This model is built-in GEOMETRY MENU for geometry
adjustment.
(1) Enter the SERVICE MODE.
(2) Press the [GREEN] key, geometry menu appears (Fig. 3).
(3) Press the []/[] key and select the adjustment item.
(4) Press the []/[] key and set the setting value.

GEOMETRY MENU

GEOMETRY

VSIZ
VPOS
VSCO
VCCO
HSIZ
HPOS
HPIN

AUTO

ADJUSTMENT ITEM SETTING VALUE

Fig.3

JVCAK30/37 B20

OSD
IF1
IF2
IF3
IF4
AGC
VLIN
RGBH
VSOF
VPOF

: 1 1 AVL

ADJUSTMENT ITEM SETTING VALUE

Fig.2

4.5.2 SELECTION OF ADJUSTMENT ITEMS

(1) Enter the SERVICE MODE.
(2) Press the []/[] key to select the adjustment item.
(3) Press the []/[] key to set the setting value.

4.5.3 HOW TO EXIT SERVICE MODE

(1) Press the [STANDARD] key.

REMOTE CONTROL UNIT key NAME

INFORMATION
Key

AV Key

FUNCTION
Key

NUMBER Key

STANDARD
Key

COLOUR Key

MENU Key

1-12 (No.YA080)

FUNCTION OF COLOUR key

RED key :
It switches the AVL to ON or OFF mode on service menu.
AVL word is visible on service menu when AVL is on.

GREEN key :
It switches to GEOMETRY adjust menu. Geometry
of the picture is adjusted in this menu.

YELLOW key :
It switches to VERTICAL SCAN DISABLE mode.
It is useful to adjust screen voltage.

BLUE key :
It is used to adjust AGC and IF automatically on service menu.

4.5.5 ADJUSTMENT ITEM

4.5.5.1 SERVICE MENU 4.5.5.2 GEOMETRY MENU

Adjustment

item

OSD HORIZONTAL POSITION OF OSD

IF1 IF COARSE ADJUSTMENT

IF2 IF FINE ADJUSTMENT

IF3 IF COARSE ADJUSTMENT FOR L-PRIME

IF4 IF FINE ADJUSTMENT FOR L-PRIME

AGC AUTOMATIC GAIN CONTROL

VLIN VERTICAL LINEARITY

RGBH RGB MODE HORIZONTAL SHIFT OFFSET

VSOF VERTICAL SIZE OFFSET for 60Hz

VPOF VERTICAL POSITION OFFSET for 60Hz

HSOF HORIZONTAL SIZE OFFSET for 60Hz

HPOF HORIZONTAL POSITION OFFSET for 60Hz

HTOF HORIZONTAL TRAPEZOID OFFSET for 60Hz

WR WHITE POINT ADJUSTMENT FOR RED

WG WHITE POINT ADJUSTMENT FOR GREEN

WB WHITE POINT ADJUSTMENT FOR BLUE

BR BIAS FOR RED

BG BIAS FOR GREEN

APR AUTOMATIC RGB PEAK REGULATION THRESHOLD

BRI BRIGHTNESS

CON CONTRAST

COL COLOUR

SHA SHARP

HUE HUE

VOL VOLUME

WR-R WHITE POINT ADJUSTMENT for RED (RGBmode)

WG-R WHITE POINT ADJUSTMENT for GREEN (RGBmode)

WB-R WHITE POINT ADJUSTMENT for BLUE (RGBmode)

FMP1 FM PRESCALER WHEN AVL IS OFF

NIP1 NICAM PRESCALER WHEN AVL IS OFF

SCP1 SCART PRESCALER WHEN AVL IS OFF

SEC1 SECAM PRESCALER WHEN AVL IS OFF

FMP2 FM PRESCALER WHEN AVL IS ON

NIP2 NICAM PRESCALER WHEN AVL IS ON

SCP2 SCART PRESCALER WHEN AVL IS ON

SEC2 SECAM PRESCALER WHEN AVL IS ON

F1H

F1L

F2H

F2L

BS1 BAND SWITCHING BYTE FOR VHF1

BS2 BAND SWITCHING BYTE FOR VHF3

BS3 BAND SWITCHING BYTE FOR UHF

CB CONTROL BYTE

OP1 PERIPHERAL OPTIONS

OP2 RECEPTION STANDARD OPTIONS

OP3 VIDEO OPTIONS

OP4 TV FEATURES

OP5 CHANNEL TABLES

TX1 TELETEXT OPTIONS

GEOM GEOMETRY OPTIONS

OP8 PIP PRESET CHANGE

HIGH BYTE OF VHF1-VHF3 CROSS-OVER FREQUENCY

LOW BYTE OF VHF1-VHF3 CROSS-OVER FREQUENCY

HIGH BYTE OF VHF3-UHF CROSS-OVER FREQUENCY

LOW BYTE OF VHF3-UHF CROSS-OVER FREQUENCY

Description

Adjustment

item

VSIZ VERTICAL SIZE for 50Hz

VPOS VERTICAL POSITION for 50Hz

VSCO VERTICAL S-CORRECTION for 50Hz

VCCO VERTICAL CORNER CORRECTION for 50Hz

HSIZ HORIZONTAL SIZE for 50Hz

HPOS HORIZONTAL POSITION for 50Hz

HPIN HORIZONTAL PINCUSHION for 50Hz

HCCO HORIZONTAL CORNER CORRECTION for 50H

HTRP HORIZONTAL TRAPEZOID for 50Hz

VZSZ VERTICAL ZOOM SIZE for 50Hz

Description

(No.YA080)1-13

4.6 ADJUSTMENTS PROCEDURE

r

4.6.1 FOCUS ADJUSTMENT

Item

FOCUS
adjustment

Measuring

instrument

Signal
generator

Remote
control unit

4.6.2 SCREEN ADJUSTMENT

Item

SCREEN
adjustment

Measuring

instrument

Remote
control unit

Test point Adjustment part Description

FOCUS VR

[On the FBT]

(1) Receive a PAL crosshatch signal.
(2) Adjust FOCUS VR on the FBT as thin as possible.

FOCUS VR

SCREEN VR

FBT

Test point Adjustment part Description

SCREEN VR

[On the FBT]

(1) Enter the SERVICE MODE.
(2) Press the [YELLOW] key to disable vertical scan.
(3) Adjust SCREEN VR. on the FBT as thin as possible.
(4) Press [YELLOW] key again to enable vertical scan.
(5) Press [STANDARD] key to leave service menu.

4.6.3 OSD ADJUSTMENT

Item

OSD
HORIZONTAL

Measuring

instrument

Remote
control unit

POSITION
adjustment

SERVICE MENU SCREEN

JVCAK30/37 B20

OSD
IF1

IF2
IF3
IF4
AGC
VLIN
RGBH
VSOF
VPOF

: 1 1 AVL

FOCUS VR

SCREEN VR

FBT

Test point Adjustment part Description

OSD (1) Enter the SERVICE MODE.

(2) Select OSD with the []/[] key.
(3) Adjust the OSD horizontal position with the []/[]

key, which shifts the reference bar on the bottom of
the SERVICE MENU horizontally, so that the OSD is
positioned on the screen center. (X=X')

Reference ba

XX'

1-14 (No.YA080)

Screen size

4.6.4 IF ADJUSTMENT

Item

Measuring

instrument

Test point Adjustment part Description

IF adjustment Remote

control unit

4.6.5 AGC AUTOMATICALLY ADJUSTMENT

Item

AGC
AUTOMATICALLY

Measuring

instrument

Remote
control unit

Test point Adjustment part Description

adjustment

JVCAK30/37 B20

OSD
IF1
IF2
IF3
IF4
AGC
VLIN
RGBH
VSOF
VPOF

: 1 1 AVL

IF1
IF2
IF3
IF4

(1) Receive a PAL colour bar pattern.
(2) Enter the SERVICE MODE.
(3) Select IF 1 with the []/[] key.
(4) Press [BLUE] key during IF 1 is highlighted, IF 1 and

IF 2 values are adjusted automatically by software.

(5) If the standard is L-prime, IF 3 and IF 4 values are

adjustment automatically when [BLUE] key is
pressed during IF 1 is highlighted.

AGC (1) Receive a 60dBµV RF signal level.

(2) Enter the SERVICE MODE.
(3) Select AGC with the []/[] key.
(4) Press [BLUE] key.
(5) The adjustment will be done automatically by

software.

(6) See the AGC indicator on SERVICE MENU, it must

be "1".

(7) Check that picture is normal at 90dBµV signal level.

IF INDICATOR AGC INDIXATOR NON

:11

4.6.6 DEFLECTION ADJUSTMENT

Item

VERTICAL
SIZE OFFSET

Measuring

instrument

Signal
generator

(60Hz)
adjustment

Remote
control unit

Very close

Screen

size

Test point Adjustment part Description

VSOF (1) Receive a NTSC crosshatch pattern of vertical

frequency 60Hz.
(2) Enter the SERVICE MODE.
(3) Select VSOF with the []/[] key.
(4) Adjust VSOF with the []/[] key until the horizontal

black lines on both the upper and lower part of the

pattern become very close to the upper and lower

horizontal sides of picture size and nearly about to

disappear.
(5) Check and readjust VSOF item if the adjustment

becomes improper after some other geometric

Picture
size
100%

adjustments are done.

Very close

(No.YA080)1-15

Item

VERTICAL
POSITION
OFFSET
(60Hz)
adjustment

Measuring

instrument

Signal
generator

Remote
control unit

Test point Adjustment part Description

VPOF (1) Receive a NTSC circle pattern of vertical frequency

60Hz.
(2) Enter the SERVICE MODE.
(3) Select VPOF with the []/[] key.
(4) Adjust VPOF with the []/[] key until the picture is

vertically centered. (C=D)
(5) Check and readjust vertical position item if the

C

adjustment becomes improper after some other

geometric adjustments are done.

D

HORIZONTAL
POSITION
OFFSET
(60Hz)
adjustment

VERTICAL
SIZE
(50Hz)
adjustment

Very close

Screen

size

Signal

HPOF (1) Receive a NTSC circle pattern signal of vertical

generator

Remote
control unit

EF

Signal

VSIZ (1) Receive a PAL crosshatch pattern of vertical

generator

Remote
control unit

Picture
size
100%

frequency 60Hz.
(2) Enter the SERVICE MODE.
(3) Select HPOF with the []/[] key.
(4) Adjust HPOF with the []/[] key until the circle

pattern is horizontally centered. (E=F)
(5) Check and readjust a horizontal position item if the

adjustment becomes improper after some other

geometric adjustments are done. Press the [MENU]

key and memorize the set value.

frequency 50Hz.
(2) Enter the SERVICE MODE.
(3) Press the [GREEN] key to enter the GEOMETRY

MENU.
(4) Select VSIZ (Vertical size) with the []/[] key.
(5) Adjust VSIZ with the []/[] key until the horizontal

black lines on both the upper and lower horizontal

sides of picture size and nearly about to disappear.
(6) Check and readjust VSIZ item if the adjustment

becomes improper after some other geometric

adjustments are done.

Very close

1-16 (No.YA080)