JVC AV-27260/AR, AV-27260/AS, AV-27260/AZ Service Manual

AV-27260

SERVICE MANUAL

COLOR TELEVISION

AV-27260 AV-27260 AV-27260

/AR

/AS

/AZ

BASIC CHASSIS

GC

TV
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
	No. 51800C
COPYRIGHT © 2001 VICTOR COMPANY OF JAPAN, LTD.
	Dec. 2001

AV-27260

SPECIFICATIONS

Items						Contents
Dimensions (W × H × D)	25-3/4” × 23-3/8” × 20-1/2” / 65.4cm × 59.1cm × 51.6cm
················································································································································································································
Mass	74.8 Ibs/34.0kg
················································································································································································································
TV RF System	CCIR(M)
················································································································································································································
Color Sound System	NTSC, BTSC System (Multi Channel Sound)
················································································································································································································
TV Receiving Channels and Frequency
VL Band	(02~06) 54MHz~88MHz
VH Band	(07~13) 174MHz~216MHz
UHF Band	(14~69) 470MHz~806MHz
················································································································································································································
CATV Receiving Channels and Frequency
Low Band	(02~06, A-8) by (02~06&01)			—
High Band	(07~13) by (07~13)
Mid Band	(A~1) by (14~22)
Super Band	(J~W) by (23~36)					(54MHz~804MHz)
Hyper Band	(W+1~W+28) by (37~64)
Ultra Band	(W+29~W+84) by (65~125)
Sub Mid Band	(A8, A4~A1) by (01, 96~99)			—
TV/CATV Total Channel	180 Channels
················································································································································································································
Intermediate Frequency
Video IF Carrier	45.75MHz
Sound IF Carrier	41.25MHz (4.5MHz)
Color Sub Carrier	3.58MHz
················································································································································································································
Power Input	120V AC, 60Hz
Power Consumption	123W
················································································································································································································
Picture Tube	27” (68cm) Measured Diagonally
High Voltage	29kV±1.3kV (at zero beam current)
················································································································································································································
Speaker	2” × 4-3/4” / 5		× 12cm Oval type ×	2
Audio Power Output	3W × 2
················································································································································································································
Video / Audio Input (1 / 2 / 3)	Video(1,3)		: 1Vp-p, 75Ø (RCA pin jack)
	Audio(1,2,3)		: 500mVrms ( -4dBs ), High Impedance (RCA pin jack)
	S-Video ( Input 1 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	: More then 0~1550mVrms (+6dBs)
(Variable)		Low impedance (400Hz when modulated 100%) (RCA pin jack)
················································································································································································································
AV Compu link EX Input	3.5mm mini jack
················································································································································································································
Antenna terminal	75Ø(VHF/UHF) Terminal, F-Type Connector
················································································································································································································
Remote Control Unit	RM-C305-1A
	(AA/R6/UM-3 battery × 2)

Design & specifications are subject to change without notice.

2	No. 51800C

AV-27260

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 (NEUTRAL) 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 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.

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.).

	AC VOLTMETER
	(HAVING 1000Ø/V,
GOOD	OR MORE SENSITIVITY)
EARTH
GROUND 0.15 F AC-TYPE
	PLACE THIS PROBE
	ON EACH EXPOSED
1500Ø 10W	METAL PART

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”.

This mark shows a fast operating fuse, the letters indicated below show the rating.

A V

POWER CORD REPLACEMENT WARNING Connecting the white line side of

power cord to “WHT” character side.

PWB

White line side

PW

WHT

No. 51800C

3

AV-27260

FEATURES

•Full-square CRT (cathode ray tube) reproduces fine textured picture in every detail.

•I2C bus control utilizes single chip ICs.

•Built in Twin Tuner system.

•Built-in HYPER-SURROUND system.

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

•3 LINE DIGITAL COMB FILTER circuit improved picture quality.

•Component input terminal for talking best advantage of Component Video Signal.

•Audio Video input terminal. (S-input ×1, V-input ×2)

•Variable audio output terminal.

•Closed-caption broadcasts can be viewed.

•With AV COMPU LINK EX terminal.

a SYSTEM BLOCK DIAGRAM

IC702

EEPROM 4k bit

IF2

SCL 1

SDA 1

	AFT2
IC701	AFT1
MAIN MICON

SCL 0

SDA 0

IC301		IC101
PIP		1 CHIP
CONTROL		CONTROL

TU001		TU001
TUNER 1		TUNER 2

IC001

MTS, TONE

SURROUND CONTROL

Remote control unit

4	No. 51800C

AV-27260

MAIN DIFFERENCE LIST

!		Model	AV-27260/AR	AV-27260/AS	AV-27260/AZ
	Part name
	MAIN PWB		SGC-1020A-M2	SGC-1025A-M2	SGC-1019A-M2
	CRT SOCKET PWB		SGC-3002A-M2	SGC-3001A-M2	SGC-3009A-M2
!	PICTURE TUBE		A68ADT25X01	A68QDN891X001	A68AJB82X02

HOW TO IDENTIFY MODELS

The difference between AV-27260/AR, AV-27260/AS and AV-27260/AZ is in the PICTURE TUBE.

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

!		Model	AV-27260/AR	AV-27260/AS			AV-27260/AZ
	Part name
!	RATING LABEL		LC31139-001A-A
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
			INDICATED AV-27260	INDICATED AV-27260			INDICATED AV-27260

INDICATED “AR”				INDICATED “AS”				INDICATED “AZ”

No. 51800C

5

AV-27260

FUNCTIONS

a FRONT PANEL

MENU

CHANNEL

VOLUME

POWER ON TIMER

		INPUT3	OPERATE
	VIDEO	AUDIO

L/MONO R

a REMOTE CONTROL UNIT

(RM-C305-1A)

TV CATV	VCR	DVD		POWER
	PIP
CHANNEL		ON/MOVE
SOURCE FREEZE SWAP				INPUT
VIDEO STATUS		1	2	3
a REAR PANEL		4	5	6
DISPLAY		7	8	9
SLEEP TIMER	100+		0 RETURN+
HYPER SURROUND
RM-C305
MUTING		+		V CHIP
		CH
VOL			VOL
			+
		CH		EXIT
MENU				PIP OFF
VCR CHANNEL		VCR/DVD
PREV NEXT		POWER		TV/VCR
REW		PLAY		FF
REC		STOP	PAUSE

OPEN/CLOSE STILL/PAUSE

TV

6	No. 51800C

AV-27260

SPECIFIC SERVICE INSTRUCTIONS

DISASSEMBLY PROCEDURE

REMOVING THE REAR COVER

1.Unplug the power supply cord.

2.Remove the 9 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 inserting the MAIN PWB into the rear cover groove.

REMOVING THE SPEAKER

• After removing the rear cover.

1.Remove the 2 screws marked H as shown in Fig.1.

2.Withdraw the speaker backward.

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

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 4 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.

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 contacting with other PW Board.

•Before turning on power, make sure that the CRT earth wire and other connectors are properly connected.

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.

REMOVING THE FRONT CONTROL AND FRONT AV INPUT PW BOARDS

• After removing the rear cover and chassis.

1.Remove the 2 screws marked F and the 2 screws marked G as shown in Fig.1.

2.Then remove the FRONT CONTROL PWB and FRONT AV INPUT PWB.

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

No. 51800C

7

AV-27260

FRONT CABINET

PICTURE TUBE

CRT SOCKET PWB

SPEAKER

H (x2)

FRONT AV INPUT PWB

CLAW

B

PIP PWB

MAIN PWB

			G (x2)
			FRONT
	F	(x2)	CONTROL PWB
			CLAW
H			B
(x2)
REAR COVER			AV SELECTOR	C
			PWB	E
			CHASSIS BASE

D (x4)

A (x7)

A (x2)

Fig.1

8	No. 51800C

AV-27260

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	SERVICE MENU
	key on the remote control unit simultaneously.
	2) The SERVICE MENU screen of Fig.1 is displayed.	PICTURE			SOUND
	3) While the SERVICE MENU is displayed, again simultaneously press	THEATER			OTHERS
	the DISPLAY and VIDEO STATUS keys to display the Fig.2 SYSTEM	PIP
		LOW LIGHT			HIGH LIGHT
	CONSTANT screen.
		RF AFC1			RF AFC2
	4) Refer to the SYSTEM CONSTANT table and check the setting items.	TU2 VCO			I2C BUS CTRL
	Where these differ, select the setting item with the MENU UP/DOWN	SELECT	BY		EXIT BY	EX
	key and adjust the setting with the MENU LEFT/RIGHT keys. (The	OPERATE	BY
						IT
	letters of the selected item are displayed in yellow.)
	5) After adjusting, release the MENU LEFT/RIGHT key to store the			Fig.1
	setting value.
	6) Press the EXIT key twice to return the normal screen.
		SYSTEM CONSTANT
(5) Receive channel setting		MODEL		:	99–99999
	Refer to the OPERATING INSTRUCTIONS(USER'S GUIDE) and set the	CCD		:	YES
		V-CHIP		:	YES
	receive channels (Channels Preset) as described.
		CAN V-CHIP		:	YES
		999999999 999
(6)	User settings	SELECT	BY		EXIT BY	EX
		OPERATE	BY
	Check the user setting items according to Table 2.					IT
	Where these do not agree, refer to the OPERATING INSTRUCTIONS (US-
	ER'S GUIDE) and set the items as described.			Fig.2

(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.

No. 51800C

9

AV-27260

TABLE 1 (System Constant setting)

Setting item

Setting content

Setting value

AV-36230A

AV-27D502A

AV-32D502A

MODEL

AV-36D302A

AV-32D302A

AV-36D502A

AV-27260A

AV-32D202A

AV-36D202A

AV-27260A

AV-32230A

AV-36260A

AV-32260A

CCD			YES			NO			YES
V-CHIP			YES			NO			YES
CAN V-CHIP			YES			NO			YES

TABLE 2 (User setting value)

Setting item	Setting value
1. Use remote controller keys
POWER	OFF
CHANNEL	CH-02
VOLUME	5
INPUT	TV
HYPER SURROUND	OFF
DISPLAY	OFF
SLEEP TIMER	0
VIDEO STATUS	CHOICE
PIP SOURCE	CH-04
PIP ON (PIP POSITION)	LEFT LOWER SIDE
2. Setting of MENU
PICTURE ADJUST
TINT	CENTER
COLOR	CENTER
PICTURE	CENTER
BRIGHT	CENTER
DETAIL	CENTER
NOISE MUTING	ON
SET VIDEO STATUS	ALL CENTER
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
LANGUAGE	ENG
CLOSED CAPTION	OFF
AUTO TUNER SETUP	TUNER MODE: AIR
CHANNEL SUMMARY	Unnecessary to set
V-CHIP	OFF
SET LOCK CODE	Unnecessary to set

10	No. 51800C