JVC AV-27F702/S Service Manual

SERVICE MANUAL

COLOR TELEVISION

AV-27F702

BASIC CHASSIS

AC

AV-27F702

CD-ROM No. SML200102

TV

/S

CONTENTS

a SPECIFICATIONS ....................................................................................................................................2

a SAFETY PRECAUTIONS ........................................................................................................................3

a FEATURES ..............................................................................................................................................4

a FUNCTIONS .............................................................................................................................................5

a SPECIFIC SERVICE INSTRUCTIONS ....................................................................................................6

a SERVICE ADJUSTMENTS ....................................................................................................................11

¤ STANDARD CIRCUIT DIAGRAM (APPENDIX) .................................................................................. 2-1

a PARTS LIST ...........................................................................................................................................29

COPYRIGHT © 2001 VICTOR COMPANY OF JAPAN, LTD.

No. 51786

Jan. 2001

AV-27F702

SPECIFICATIONS

Items Contents

Dimensions (W × H × D)

················································································································································································································

Mass

················································································································································································································

TV RF System

················································································································································································································

Color Sound System

················································································································································································································

TV Receiving Channels and Frequency

VL Band

VH Band

UHF Band

················································································································································································································

CATV Receiving Channels and Frequency

Low Band

High Band

Mid Band

Super Band

Hyper Band

Ultra Band

Sub Mid Band

TV/CATV Total Channel

················································································································································································································

Intermediate Frequency

Video IF Carrier

Sound IF Carrier

Color Sub Carrier

················································································································································································································

Power Input

Power Consumption

················································································································································································································

Picture Tube

High Voltage

················································································································································································································

Speaker

Audio Power Output

················································································································································································································

Video / Audio Input (1 / 2 / 3)

29-7/8” × 23-3/8” × 19-3/4” / 75.8cm × 59.3cm × 50.0cm

101.2 lbs / 46 kg

CCIR(M)

NTSC, BTSC System (Multi Channel Sound)

(02~06) 54MHz~88MHz

~13) 174MHz~216MHz

(07

(14

~69) 470MHz~806MHz

(02~06, A-8) by (02~06&01)

(07~13) by (07~13)

(A~1) by (14~22)

(J~W) by (23~36) (54MHz~804MHz)

(W+1~W+28) by (37~64)

(W+29~W+84) by (65~125)

(A8, A4~A1) by (01, 96~99)

180 Channels

45.75MHz

41.25MHz (4.5MHz)

3.58MHz

120V AC, 60Hz

140W / 2.0A

27” (68cm) Measured Diagonally

30kV±1kV (at zero beam current)

2” × 4-3/4” / 5 × 12cm Oval type × 2

5W × 2

Video(1,2,3) : 1Vp-p, 75Ø (RCA pin jack)

Audio(1,2,3) : 500mVrms ( -4dBs ), High Impedance (RCA pin jack)

S-Video ( Input 1 / 3 Over )

Y : 1Vp-p Positive (negative sync provided, when terminated with 75Ø)

C : 0.286Vp-p (burst signal, when terminated with 75Ø)

Component Input ( Input 2 )

Y : 1Vp-p positive (negative sync provided, when terminated with 75Ø)

PB/PR : 0.7Vp-p 75 Ø

—

—

················································································································································································································

Audio Output

(Variable / Fix : Selectable)

················································································································································································································

AV Compu link EX Input

················································································································································································································

Antenna terminal

················································································································································································································

Remote Control Unit

Variable : More then 0~1550mVrms (+6dBs)

Low impedance (400Hz when modulated 100%)

Fix : 500mVrms(-4dBs)

Low impedance (400Hz when modulated 100%)

3.5mm mini jack

75Ø(VHF/UHF) Terminal, F-Type Connector

RM-C303G-1A

(AA/R6/UM-3 battery × 2)

(RCA pin jack)

(RCA pin jack)

Design & specifications are subject to change without notice.

2 No. 51786

GOOD
EARTH
GROUND

0.15 µF AC-TYPE

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

PLACE THIS PROBE
ON EACH EXPOSED
METAL PART

1500Ø 10W

A V

This mark shows a fast

POWER CORD
REPLACEMENT WARNING

Connecting thr white line side of
power cord to “WHT” character side.

operating fuse, the
letters indicated below
show the rating.

PWB

WHT

PW

White line side

SAFETY PRECAUTIONS

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. Use isolation transformer when hot chassis.
The chassis and any sub-chassis contained in some products are
connected to one side of the AC power line. An isolation transformer
of adequate capacity should be inserted between the product and
the AC power supply point while performing any service on some
products when the HOT chassis is exposed.

5. Don't short between the LIVE side ground and ISOLATED (NEU-

TRAL) 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 with a measuring apparatus (oscilloscope etc.) the LIVE
side GND and ISOLATED(NEUTRAL) side GND or EARTH side
GND at the same time.
If above note will not be kept, a fuse or any parts will be broken.

6. If any repair has been made to the chassis, it is recommended that
the B1 setting should be checked or adjusted (See ADJUSTMENT
OF B1 POWER SUPPLY).

7. 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.

8. 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 10kØ 2W resistor to the anode button.

9. 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.

No. 51786 3

AV-27F702

10. 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,
screwheads, earphone jack, control shafts, etc.) to be sure the prod­uct is safe to operate without danger of electrical shock.

(1) 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 1100V 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.

(2) 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 1000 ohms per volt or more sensitivity in the following manner.
Connect a 1500Ø 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.).

11 . High voltage hold down circuit check.

After repair of the high voltage hold down circuit, this circuit shall be
checked to operate correctly.
See item “How to check the high voltage hold down circuit”.

AV-27F702

FEATURES

Full-flat CRT (cathode ray tube) reproduces fine textured picture in

•

every detail.
I2C bus control utilizes single chip ICs.

•

Built-in HYPER-SURROUND system.

•

Built-in BBE.

•

3 LINE DIGITAL COMB FILTER circuit improved picture quality.

•

Component input terminal for talking best advantage of Component

•

Video Signal.

a SYSTEM BLOCK DIAGRAM

IC702

E2PROM 4k bit

SCL 1 SDA 1

Audio Video input terminal. (S-input ×2, V-input ×3)

•

Variable/Fix audio output terminal.

•

Closed-caption broadcasts can be viewed.

•

With AV COMPU LINK EX terminal.

•

Remote

control

unit

SCL 0 SDA 0

IC701

MAIN MICON

IC101

1 CHIP

CONTROL

AFC

IC501

AVSW

CONTROL

TU001

TUNER

IC001

MTS, TONE

SURROUND CONTROL

4 No. 51786

FUNCTIONS

a FRONT PANEL

AV-27F702

a FRONT PANEL DOOR OPENED

a REAR PANEL

a REMOTE CONTROL UNIT

(RM-C303G-1A)

2

No. 51786 5

AV-27F702

SPECIFIC SERVICE INSTRUCTIONS

DISASSEMBLY PROCEDURE

REMOVING THE REAR COVER

1. Unplug the power supply cord.

2. Remove the 12 screws marked A as shown in Fig.1.

3. Withdraw the REAR COVER toward you.

[CAUTION]

When reinstalling the rear cover, carefully push it inward after in-

•

serting the MAIN PWB into the rear cover groove.

REMOVING THE CHASSIS

After removing the rear cover.

•

1. Slightly raise the both sides of the chassis by hand and remove the
3 claws marked B under the chassis from the front cabinet as
shown in Fig.1.

2. Withdraw the chassis backward along the rail in the arrow direction
marked C as shown in Fig.1.

(If necessary, take off the wire clamp, connector’s etc.)

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

*

that the CRT earth wire is connected to the CRT SOCKET PWB
and the MAIN PWB.

REMOVING THE TERMINAL BOARD

After removing the rear cover.

•

1. Remove the 6 screws marked D as shown in Fig.1.

2. When you pull out the TERMINAL BOARD in the direction of arrow
marked E as shown in Fig.1, it can be removed.

REMOVING THE DAF PW BOARD

After removing the rear cover and chassis.

•

1. Lift the right side of the DAF PWB while pressing the PWB stopper
marked J and claw marked K in the arrow direction marked L as
shown in Fig.1.

2. Then remove the DAF PWB.

(If necessary, take off the wire, connector’s etc.)

REMOVING THE SPEAKER

After removing the rear cover.

•

1. Remove the 4 screws marked M as shown in Fig.1.

2. Withdraw the speaker backward.

3. Follow the same steps when removing the other hand speaker.

CHECKING THE MAIN PW BOARD

1. To check the back side of the MAIN PW Board.

1) Pull out the chassis. (Refer to REMOVING THE CHASSIS).

2) Erect the chassis vertically so that you can easily check the back

side of the MAIN PW Board.

[CAUTION]

When erecting the chassis, be careful so that there will be no con-

•

tacting with other PW Board.
Before turning on power, make sure that the CRT earth wire and

•

other connectors are properly connected.

REMOVING THE FRONT AND POWER SW PW BOARDS

After removing the rear cover and chassis.

•

1. Remove the 4 screws marked F as shown in Fig.1.

2. Then remove the FRONT PWB and POWER SW PWB.

(If necessary, take off the wire, connector’s etc.)

REMOVING THE LF PW BOARD

After removing the rear cover and chassis.

•

1. Lift the left side of the LF PWB while pressing the 2 PWB stoppers
marked G in the arrow direction marked H as shown in Fig.1.

2. Then remove the LF PWB.

(If necessary, take off the wire, connector’s etc.)

WIRE CLAMPING AND CABLE TYING

1. Be sure 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.

6 No. 51786

FRONT CABINET

AV-27F702

SPEAKER

M

(x4)

CRT SOCKET PWB

REAR COVER

POWER SW PWB

CLAW

B

PWB
STOPPER

G

FRONT PWB

H

LF PWB

F

(x4)

CLAW

PWB

G

STOPPER

CLAW

K

DAF PWB

L

B

C

PWB STOPPER

J

CHASSIS

MAIN PWB

E

D

(x6)

A

(x12)

Fig.1

No. 51786 7

AV-27F702

MEMORY IC REPLACEMENT

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.

2. Memory IC replacement procedure

Procedure Screen display

(1) Power off

Switch off the power and disconnect the power cord from the outlet.

(2) Replace the memory IC

Initial value must be entered into the new IC.

(3) Power on

Connect the power cord to the outlet and switch on the power.

(4) System constant check and setting

1) Press SLEEP TIMER key and, while the indication of “SLEEP TIMER
0 MIN.” is being displayed, press DISPLAY key and VIDEO STATUS

key on the remote control unit simultaneously.

2) The SERVICE MENU screen of Fig.1 is displayed.

3) While the SERVICE MENU is displayed, again simultaneously press
the DISPLAY and VIDEO STATUS keys to display the Fig.2 SYSTEM
CONSTANT screen.

4) Refer to the SYSTEM CONSTANT table and check the setting items.
Where these differ, select the setting item with the MENU UP/DOWN
key and adjust the setting with the MENU LEFT/RIGHT keys. (The
letters of the selected item are displayed in yellow.)

5) After adjusting, release the MENU LEFT/RIGHT key to store the
setting value.

6) Press the EXIT key twice to return the normal screen.

(5) Receive channel setting

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

(6) User settings

Check the user setting items according to Table 2.
Where these do not agree, refer to the OPERATING INSTRUCTIONS (US­ER'S GUIDE) and set the items as described.

SERVICE MENU

PICTURE SOUND
THEATER OTHERS

LOW LIGHT HIGH LIGHT
RF AFC
VCO(CW) I2C BUS CTRL

SELECT BY
OPERATE BY

Fig.1

SYSTEM CONSTANT

MODEL :99–
TM CORR. : NO
CCD : YES
V-CHIP : YES
CAN V-CHIP : NO

EXIT BY

99999

999999999 999

SELECT BY
OPERATE BY

Fig.2

EXIT BY

EX

IT

EX

IT

(7) SERVICE MENU setting

Verify what to set in the SERVICE MENU, and set whatever is
necessary.(Fig.1) Refer to the SERVICE ADJUSTMENT for setting.

8 No. 51786

AV-27F702

TABLE 1 (System Constant setting)

Setting item Setting content Setting value

AV-27F802 AV-32F802 AV-36F802 AV-27F702 AV-32F702

MODEL AV-27F702

AV-36D502 AV-32D502 AV-27D502 AV-36F702

AV-32D302 AV-36D302 AV-32D202 AV-36D202

AV-36230 AV-32230 AV-36260 AV-32260 AV-27260

TM CORR.

CCD

V-CHIP

CAN V-CHIP

YES NO

YES NO

YES NO

YES NO

TABLE 2 (User setting value)

Setting item Setting value

1. Use remote controller keys

POWER OFF
CHANNEL CH-02
VOLUME 05
INPUT TV
HYPER SURROUND OFF
BBE ON
DISPLAY OFF
SLEEP TIMER 0
VIDEO STATUS CHOICE

2. Setting of MENU

PICTURE ADJUST

TINT CENTER
COLOR CENTER
PICTURE CENTER
BRIGHT CENTER
DETAIL CENTER
NOISE MUTING ON
SET VIDEO STATUS ALL CENTER

NO

YES

YES

NO

SOUND ADJUST

BASS CENTER
TREBLE CENTER
BALANCE CENTER
MTS STEREO

CLOCK/TIMERS

SET CLOCK Unnecessary to set
ON/OFF TIMER NO

INITIAL SETUP

TV SPEAKER ON
AUDIO OUT FIX
COMPONENT-IN NO
LANGUAGE ENG
CLOSED CAPTION OFF
AUTO TUNER SETUP Unnecessary to set
CHANNEL SUMMARY Unnecessary to set
V-CHIP OFF
SET LOCK CODE Unnecessary to set

No. 51786 9