JVC AV27260A5 - Service Manual Immediate Download

SERVICE MANUAL

AV-27D502

COLOR TELEVISION

BASIC CHASSIS

GC

No. 51797C

Dec. 2001

TV

AV-27D502 /AR

AV-27D502 /AS

CONTENTS

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

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

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

a MAIN DIFFERENCE LIST ........................................................................................................................5

a HOW TO IDENTIFY MODELS ..................................................................................................................5

a FUNCTIONS .............................................................................................................................................6

a SPECIFIC SERVICE INSTRUCTIONS ....................................................................................................7

a SERVICE ADJUSTMENTS ....................................................................................................................12

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

a PARTS LIST ...........................................................................................................................................31

AV-27D502

2

No. 51797C

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

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)

Audio Output

(Variable)

AV Compu link EX Input

Antenna terminal

Remote Control Unit

29-5/8"

× 23-1/4" × 19-1/2" / 75.2cm × 59.1cm × 49.4cm

71.3 Ibs/32.4kg

CCIR(M)

NTSC, BTSC System (Multi Channel Sound)

(02

~06) 54MHz~88MHz

(07

~13) 174MHz~216MHz

(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

123W

27" (68cm) Measured Diagonally

29kV±1.3kV (at zero beam current)

2"

× 4-3/4" / 5 × 12cm Oval type × 2

5W

× 2

Video(1,3)

: 1Vp-p, 75Ø (RCA pin jack)

Audio(1,2,3)

: 500mVrms ( -4dBs ), High Impedance (RCA pin jack)

S-Video ( Input 1 / 2 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

Variable : More then 0

~1550mVrms (+6dBs)

Low impedance (400Hz when modulated 100%) (RCA pin jack)

3.5mm mini jack

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

RM-C301G-2A

(AA/R6/UM-3 battery

× 2)

Design & specifications are subject to change without notice.

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

AV-27D502

No. 51797C

3

SAFETY PRECAUTIONS

1. The design of this product contains special hardware, many circuits

and components specially for safety purposes. For continued pro-

tection, 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 manufactur-

er's warranty and will further relieve the manufacturer of responsi-

bility 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 recom-

mended 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 dif-

ference 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.

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 dam-

age, 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 com-

ponents that indicate evidence of overheating should be replaced.

Always use the manufacturer's replacement components.

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 prod-

uct 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 hav-

ing 1000 ohms per volt or more sensitivity in the following manner.

Connect a 1500Ø 10W resistor paralleled by a 0.15µF AC-type ca-

pacitor between an exposed metal part and a known good earth

ground (water pipe, etc.). Measure the AC voltage across the resis-

tor with the AC voltmeter. Move the resistor connection to each ex-

posed metal part, particularly any exposed metal part having a re-

turn 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".

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 the 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

AV-27D502

4

No. 51797C

FEATURES

· Full-square CRT (cathode ray tube) reproduces fine textured pic-

ture in every detail.

· I2C bus control utilizes single chip ICs.

· Built in Twin Tuner system.

· Built-in HYPER-SURROUND system.

· Built-in BBE.

· Adoption of the Picture-In-Picture (PIP) function.

· 3 LINE DIGITAL COMB FILTER circuit improved picture quality.

IC702

EEPROM 4k bit

IC701

MAIN MICON

IF2

SCL 1

SDA 1

SCL 0

SDA 0

AFT2

AFT1

Remote

control

unit

IC301

PIP

CONTROL

IC001

MTS, TONE

SURROUND CONTROL

TU001

TUNER 1

TU001

TUNER 2

IC101

1 CHIP

CONTROL

· Component input terminal for taking best advantage of Component

Video Signal.

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

· Variable audio output terminal.

· Closed-caption broadcasts can be viewed.

· With AV COMPU LINK EX terminal.

a SYSTEM BLOCK DIAGRAM

AV-27D502

No. 51797C

5

MAIN DIFFERENCE LIST

HOW TO IDENTIFY MODELS

Model

Part name

AV-27D502/AR

AV-27D502/AS

MAIN PWB

SGC-1002A-M2

SGC-1001A-M2

CRT SOCKET PWB

SGC-3002A-M2

SGC-3001A-M2

! PICTURE TUBE

A68ADT25X01

A68QDN891X001

!

Model

Part name

AV-27D502/AR

AV-27D502/AS

!

RATING LABEL

LC31139-001A-A

GQ30032-001A-A

!

------------------------------------------------------------------------------------------------

The difference between AV-27D502/AR and AV-27D502/AS is in the PICTURE TUBE.

As the result of the difference in PICTURE TUBE, the MAIN PWB also differ.

INDICATED AV-27D502

INDICATED

"AR"

INDICATED AV-27D502

INDICATED

"AS"

GQ30032-001A-A