Jvc Ks-ax770 User manual

SERVICE MANUAL

2003/03

KS-AX7700

POWER AMPLIFIER

49809200303 KS-AX7700

TABLE OF CONTENTS

1 Important Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2

2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3

3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6

Area suffix

J ------------ Northern America

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KS-AX7700

1-2 (No.49809)

SECTION 1

Important Safety Precautions

1.1 Safety Precautions

!Burrs formed during molding may be left over on some parts of the chassis. Therefore,

pay attention to such burrs in the case of preforming repair of this system.

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TEL 13942296513 QQ 376315150 892498299

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KS-AX7700

(No.49809)1-3

SECTION 2

Disassembly method

CAUTION:

If electricity is connected during disassembly, it must be a no

load current.

If it is load current, be sure to attach a heat sink to the power-

amp IC.

This will be damaged if the above precautions arenotfollowed,

as it does not have a sub heat sink attached to it.

2.1 Removing the bottom cover (see Fig. 1)

(1) From the bottom side of the main unit, remove the 4 screws

Aretaining the bottom cover.

(2) Then remove the 6 screws Bretaining the bottom cover.

(3) Remove the bottom cover.

Fig.1

2.2 Removing the main board (see Fig. 2 to 8)

(1) Remove the bottom cover from the main unit.

(2) Loosen and remove the 2 screws Cretaining the top plate

on the main unit.

(Stoppers are attached to the backs of the Cscrews so that

they cannot be removed easily.)

(3) Remove the 3 volume knobs on top of the control panel. If

it cannot be pulled out easily, insert a scale or suitable lever

between the base of the volume knob and the control panel

so that the volume knob is raised a little above the surface

and then remove it.

(Be careful when inserting a lever etc. not to scratch

the surface of the control panel).

(4) Remove the 4 screws Dretaining the control panel. Then

detach the control panel and the switch knob.

Fig.2

Fig.3

Fig.4

Bottom cove

r

B

A

B

Top plate

CC

DD

Volume knob

Switch knob

(Side view)

Scale or suitable lever

Volume knob

Control panel

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KS-AX7700

1-4 (No.49809)

(5) Remove the 6 screws Eretaining the panels on both sides

of the main unit.

(6) Remove the 13 screws Fattaching the main board to the

bottom of the main unit.

(The GND wire that protrudes from the main board

must be re-installed to its original position during re-

assembly.)

(7) To remove the wire ass'y, lift up the main board a little.

Fig.5

Fig.6

Fig.7

Fig.8

Rear panel

E

Front panel

E

GND wire

Main board

F

Main board

Wire assemb'y

(Side view)

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KS-AX7700

(No.49809)1-5

2.3 Removing the CCFL board (see Fig. 9 to 12)

(1) Remove the bottom cover.

(2) Then remove the Main board.

(3) From the bottom side of the main unit, remove the 4 screws

Gretaining the CCFL cover.

(4) Then remove the insulation sheet on top of the CCFL

board.

(5) Remove the 4 screws Hretaining the CCFL board.

(6) Remove the CCFL board by sliding it a little towards the

arrow mark.

Fig.9

Fig.10

Fig.11

Fig.12

CCFL cover

G

G G

CCFL board

Insulation sheet

H

CCFL board

H

This section is cought

by the portion.

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TEL 13942296513 QQ 376315150 892498299

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KS-AX7700

1-6 (No.49809)

SECTION 3

Adjustment

3.1 Adjustment method

(1) Check the voltage and frequency of the secondary toroidal

coil.

FREQUENCY:24.35kHz±10Hz

VOLTAGE VALUE:55Vp-p

(2) Measure the secondary toroidal coil, if the standard

frequency value of 24.35 kHz ±10 Hz is not attained,

measure the R760 terminal, then adjust the VR701 so that

the R760 terminal becomes 24.25 kHz± 10Hz.

NOTE:

When measuring, adjust and apply power with no

signal or load on each board.

DC/DC CONVERTER SECOND GENERATOR SWITCHING

TEST SET

FREQUENCY COUNTER

Main board

(+)

(

-

)

POWER SUPPLY

14.4V

R760

Measuring

Points

88Vp-p

±2.5V

TEST ITEM

VOLTAGE TEST

FREQUENCY CHECK

88Vp-p±2.5V

24.350KHz±10Hz

OSCILLOSCOPE

VOLT/DIV: 10

TIME/DIV: 10msec

VARIABLE: MINIMUM

SPECIFICATION CONDITION

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TEL 13942296513 QQ 376315150 892498299

http://www.xiaoyu163.com

KS-AX7700

(No.49809)1-7

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TEL 13942296513 QQ 376315150 892498299

http://www.xiaoyu163.com

(No.49809)

AV & MULTIMEDIA COMPANY MOBILE ENTERTAINMENT CATEGORY 10-1,1chome,Ohwatari-machi,Maebashi-city,371-8543,Japan

VICTOR COMPANY OF JAPAN, LIMITED

200303WPC

Printed in Japan

KS-AX7700

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TEL 13942296513 QQ 376315150 892498299

http://www.xiaoyu163.com

SCHEMATIC DIAGRAMS

POWER AMPLIFIER

No.49809SCH

2003/03

KS-AX7700

Area Suffix

J Northern America

Contents

Block diagrams

Standard schematic diagrams

Printed circuit boards

2-1

2-2

2-8~9

CD-ROM No.SML200303

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TEL 13942296513 QQ 376315150 892498299

http://www.xiaoyu163.com

KS-AX7700

!Burrs formed during molding may be left over on some parts of the chassis. Therefore,

pay attention to such burrs in the case of preforming repair of this system.

Safety precaution

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TEL 13942296513 QQ 376315150 892498299

http://www.xiaoyu163.com

JVC KS-AX770 User manual

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