Page 1
49809200303
KS-AX7700
SERVICE MANUAL
POWER AMPLIFIER
KS-AX7700
Area suffix
J ------------ Northern America
TABLE OF CONTENTS
1 Important Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LTD.
No.49809
2003/03
Page 2
KS-AX7700
1.1 Safety Precautions
SECTION 1
Important 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.
1-2 (No.49809)
Page 3
SECTION 2
r
A
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 poweramp IC.
This will be damaged if the above precautions are not followed,
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
A retaining the bottom cover.
(2) Then remove the 6 screws B retaining the bottom cover.
(3) Remove the bottom cove r.
KS-AX7700
B
Bottom cove
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 C retaining the top plate
on the main unit.
(Stoppers are attached to the backs of the C screws so that
they cannot be removed easily.)
(3) Remove the 3 volu me kn obs 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 th e 4 screws D retaining the control panel . Then
detach the control panel and the switch knob.
A
B
Fig.1
Top plate
C
Fig.2
Volume knob
C
DD
Switch knob
Fig.3
Volume knob
Scale or suitable lever
Control panel
(Side view)
Fig.4
(No.49809)1-3
Page 4
KS-AX7700
(5) Remove the 6 screws E retaining the panels on both sides
of the main unit.
(6) Remo ve the 13 screws F attaching 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 duri ng reassembly.)
Rear panel
E
Fig.5
Front panel
E
Fig.6
F
(7) To remove the wire ass'y, lift up the main board a little.
GND wire
Main board
F
Fig.7
Main board
Wire assemb'y
(Side view)
Fig.8
1-4 (No.49809)
Page 5
2.3 Removing the CCFL board (see Fig. 9 to 12)
(1) Remove the bottom cove r.
(2) Then remove the Main board.
(3) From the bottom side of the main unit, remove the 4 screws
G retaining the CCFL cover.
(4) Then remove the insulation sheet on top of the CCFL
board.
(5) Remove the 4 screws H retaining the CCFL board.
KS-AX7700
G
CCFL cover
G G
Fig.9
CCFL board
Insulation sheet
Fig.10
CCFL board
(6) Remove the CCFL board by sliding it a little towards the
arrow mark.
H
H
Fig.11
This section is cought
by the portion.
Fig.12
(No.49809)1-5
Page 6
KS-AX7700
3.1 Adjustment method
(1) Check the voltage and frequency of the secondary toroidal
coil.
FREQUENCY:24.35kHz±10Hz
VOLTAGE VALUE:55Vp-p
SECTION 3
Adjustment
FREQUENCY COUNTER
TEST SET
Main board
(+)
(
POWER SUPPLY
14.4V
-
)
(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 ITEM
VOLTAGE TEST
FREQUENCY CHECK
SPECIFICATION CONDITION
88Vp-p±2.5V
24.350KHz±10Hz
OSCILLOSCOPE
VOLT/DIV: 10
TIME/DIV: 10msec
VARIABLE: MINIMUM
Measuring
Points
R760
88Vp-p
±2.5V
1-6 (No.49809)
Page 7
KS-AX7700
(No.49809)1-7
Page 8
KS-AX7700
VICTOR COMPANY OF JAPAN, LIMITED
AV & MULTIMEDIA COMPANY MOBILE ENTERTAINMENT CATEGORY 10-1,1chome,Ohwatari-machi,Maebashi-city,371-8543,Japan
(No.49809)
Printed in Japan
200303WPC
Loading...