JVC AX-V8000 User manual

SERVICE MANUAL
COPYRIGHT © 2004 VICTOR COMPANY OF JAPAN, LIMITED No.MB177
2004/3
AUDIO/VIDEO CONTROL AMPLIFIER
MB17720043
AX-V8000
TABLE OF CONTENTS
1 PRECAUTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-2
2 SPECIFIC SERVICE INSTRUCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-3
3 DISASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
4 ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-17
5 TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-20
Area suffix
UP --------------------------- Korea
AUDIO/VIDEO CONTROL AMPLIFIER
STANDBY/ON
STANDBY
PHONES
DIMMER
CC CONVER
DOOR
UP
DOOR
DOWN
MASTER VOLUME
S-VIDEODIGITAL VIDEO L—AUDIO—R
VIDEO
CHANNEL
TV/VIDEO
MUTING
DVD
ON/OFF ON/OFF
STANDBY/ON STANDBY/ON
STANDBY
TV/CATV/DBS VCR 1
ON
DVD MULTI CD
CDR
PHONO
TAPE/MD
EXT 7.1CH
ANALOG/DIGITAL
CC CONVERTER
EFFECT
LIVENESS
SOUND
TEST
THX
EX/ES/7.1
ANALOG DIRECT
SLEEP DIMMER
FM MODE
DSP SURR/DSPSURROUND
RETURN 100+
OFF
INPUT
SET
SETUP
MENU
ADJUST
MENU
DVD
MENU EXIT
TEXT
DISPLAY
123
456
7
/P 89
10 +100
TV VOL
VOLUME
TUNING
STOP PAUSE
LIGHT
FF/
/ REW
REC
PLAY
DOWN U P
RM-SRXDP20J REMOTE CONTROL
A/V CONTROL RECEIVER
VCR 1 VCR 2
FM/AMVIDEOTV/DBS
ZONE 2
TRANSMITLEARN
ZONE 1
ZONE 2
ZONE 1
ZONE 2 LEARNZONE 1
TV
CATV/
DBS

1-2 (No.MB177)
SECTION 1
PRECAUTION
1.1 Safety Precautions
(1) This design of this product contains special hardware and
many circuits and components specially for safety purpos-
es. 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. Services should be per-
formed by qualified personnel only.
(2) Alterations of the design or circuitry of the product should
not be made. Any design alterations of the product should
not be made. Any design alterations or additions will void
the manufacturers warranty and will further relieve the
manufacture 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 characteris-
tics are often not evident from visual inspection nor can the
protection afforded by them necessarily be obtained by us-
ing replacement components rated for higher voltage, watt-
age, etc. Replacement parts which have these special
safety characteristics are identified in the Parts List of Ser-
vice Manual. Electrical components having such features
are identified by shading on the schematics and by ( ) on
the Parts List in the Service Manual. The use of a substitute
replacement which does not have the same safety charac-
teristics as the recommended replacement parts shown in
the Parts List of Service Manual may create shock, fire, or
other hazards.
(4) The leads in the products are routed and dressed with ties,
clamps, tubings, barriers and the like to be separated from
live parts, high temperature parts, moving parts and/or
sharp edges for the prevention of electric shock and fire
hazard. When service is required, the original lead routing
and dress should be observed, and it should be confirmed
that they have been returned to normal, after reassem-
bling.
(5) Leakage shock hazard testing
After reassembling the product, always perform an isola-
tion check on the exposed metal parts of the product (an-
tenna terminals, knobs, metal cabinet, screw heads,
headphone jack, control shafts, etc.) to be sure the product
is safe to operate without danger of electrical shock.Do not
use a line isolation transformer during this check.
• Plug the AC line cord directly into the AC outlet. Using a
"Leakage Current Tester", measure the leakage current
from each exposed metal parts of the cabinet, particular-
ly any exposed metal part having a return path to the
chassis, to a known good earth ground. Any leakage cur-
rent must not exceed 0.5mA AC (r.m.s.).
• Alternate check method
Plug the AC line cord directly into the AC outlet. Use an
AC voltmeter having, 1,000Ωper volt or more sensitivity
in the following manner. Connect a 1,500Ω10W resistor
paralleled by a 0.15µF AC-type capacitor between an ex-
posed metal part and a known good earth ground.
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. Voltage measured any must
not exceed 0.75 V AC (r.m.s.). This corresponds to 0.5
mA AC (r.m.s.).
1.2 Warning
(1) This equipment has been designed and manufactured to
meet international safety standards.
(2) It is the legal responsibility of the repairer to ensure that
these safety standards are maintained.
(3) Repairs must be made in accordance with the relevant
safety standards.
(4) It is essential that safety critical components are replaced
by approved parts.
(5) If mains voltage selector is provided, check setting for local
voltage.
1.3 Caution
Burrs formed during molding may be left over on some parts
of the chassis.
Therefore, pay attention to such burrs in the case of pre-
forming repair of this system.
1.4 Critical parts for safety
In regard with component parts appearing on the silk-screen
printed side (parts side) of the PWB diagrams, the parts that are
printed over with black such as the resistor ( ), diode ( )
and ICP ( ) or identified by the " " mark nearby are critical
for safety. When replacing them, be sure to use the parts of the
same type and rating as specified by the manufacturer.
(This regulation dose not Except the J and C version)
Good earth ground
Place this
probe on
each exposed
metal part.
AC VOLTMETER
(Having 1000
ohms/volts,
or more sensitivity)
1500 10W
0.15 F AC TYPE

(No.MB177)1-3
SECTION 2
SPECIFIC SERVICE INSTRUCTIONS
This service manual does not describe SPECIFIC SERVICE INSTRUCTIONS.

1-4 (No.MB177)
SECTION 3
DISASSEMBLY
3.1 Main body section
3.1.1 Removing the top cover
(See Fig.1)
(1) From the top sides of the main body, remove the nine
screws Aattaching the top cover.
(2) From the back side of the main body, remove the three
screws Battaching the top cover.
(3) Take out the top cover upward in the direction of the arrow.
3.1.2 Removing the side panel (L) & side panel (R) & stay bkt
(See Figs.1 and 2)
• Prior to performing the following procedure, remove the top
cover.
(1) From the left sides of the main body, remove the four
screws Cattaching the side panel (L). (See fig.1)
(2) From the right sides of the main body, remove the three
screws Cattaching the side panel (R). (See fig.1)
(3) From the top side of the main body, remove the four screws
Dattaching the side panel (L) and the side panel (R). (See
fig.2)
(4) Remove the four screws Eattaching the stay bkt, and take
out the stay bkt. (See fig.2)
Fig.1
Fig.2
Top cover
C
CC
B
Side panel (R) Side panel (L)
A
E
E
DD
Side panel(L)
Stay bkt
Side panel(R)
E

(No.MB177)1-5
3.1.3 Removing the front panel assembly
(See Figs.3 to 6)
• Prior to performing the following procedure, remove the top
cover, side panels and stay bkt.
(1) From the top side of the main body, cut off the tie band
fixing the wire. (See fig.3)
(2) Remove the three screws Fattaching the front panel
assembly. (See fig.3)
(3) Remove the screw Gattaching the lug wire. (See fig.3)
(4) From the bottom side of the main body, remove the four
screws Hattaching the front panel assembly and take out
the front panel assembly forward. (See fig.4)
(5) From the front side of the main body, disconnect the wire
from the connectors CN971, CN977, CN983 and CN985
on the system control board. (See fig.5)
(6) From the reverse side of the front panel assembly,
disconnect the wire from the connector CN973 on the front
AV in board. (See fig.6)
(7) Disconnect the wire from the connector CN373 on the front
DIGITAL in board. (See fig.6)
Reference:
When attaching the screws Fand screw G, attach the lug wire
with it.
Fig.3
Fig.4
Fig.5
Fig.6
F
(fixing the
lug wire)
G
Tie band
Front panel assembly
H
Front panel
assembly
System control board
CN985
CN971CN977CN983
CN973
Front AV in board
CN373
Front DIGITAL in board

1-6 (No.MB177)
3.1.4 Removing the rear panel
(See Fig.7)
• Prior to performing the following procedure, remove the top
cover, side panels and stay bkt.
(1) From the top side on the main body, remove the protect
cover and the solders from the two solder points on the AC
inlet.
(2) From the bottom side on the main body, remove the four
screws Jattaching the rear panel.
(3) From the back side on the main body, remove the forty-six
screws K, two screws Land three screws Mattaching each
board to the rear panel.
3.1.5 Removing the audio signal 3 board & compu link board
(See Figs.7 and 8)
• Prior to performing the following procedure, remove the top
cover, side panels and stay bkt.
(1) From the top side of the main body, cut off the tie band
fixing the wire. (See fig.8)
(2) Disconnect the wire from the connector CN201 on the
audio signal 1 board. (See fig.8)
(3) From the back side of the main body, remove the two
screws Lattaching the audio signal 3 board to the rear
panel. (See fig.7)
(4) From the top side of the main body, disconnect the wire
from the connector CN302 on the compu link board. (See
fig.8)
(5) Disconnect the wire from the connector CN207 on the
audio signal 1 board. (See fig.8)
(6) From the back side of the main body, remove the three
screws Mattaching the compu link board to the rear panel.
(See fig.7)
Fig.7
Fig.8
3.1.6 Removing the Y/C separator board
(See Fig.9)
• Prior to performing the following procedure, remove the top
cover, side panels and stay bkt.
(1) From the top side of the main body, cut off the tie band
fixing the wire.
(2) Disconnect the connectors CN481 and CN482 on the Y/C
separator board, and take out the Y/C separator board
upward.
Fig.9
J
KK
AC inlet
Black
Red
Solder part
KJ J
K
K
Protect cover
L
K
Rear panel
KK
KM
Tie bands
Audio signal
3 board
CN201
Audio signal
1 board
Compu link
board
CN207 CN302
Y/C separator
board
CN481
CN482
Tie bands

(No.MB177)1-7
3.1.7 Removing the system control board
(See Figs.10 and 11)
• Prior to performing the following procedure, remove the top
cover, side panels, stay bkt and front panel assembly.
(1) From the top side of the main body, cut off the tie bands
fixing the wires. (See fig.10)
(2) Disconnect the wire from the connector CN45 on the power
2 board . (See fig.10)
(3) Disconnect the wire from the connector CN25 on the
power/ fuse board. (See fig.10)
(4) Disconnect the wire from the connector CN234, CN208 on
the audio signal 1 board. (See fig.10)
(5) From the front side of the main body, disconnect the wires
from the connector CN963, CN964 and CN981 on the
system control board. (See fig.11)
(6) Remove the three plastic rivet, and take out the system
control board. (See fig.11)
Fig.10
Fig.11
3.1.8 Removing the DSP 1 board & DSP 2 board & shield cover
(See Fig.12)
• Prior to performing the following procedure, remove the top
cover, side panels, stay bkt, front panel assembly and rear
panel.
(1) From the top side of the main body, disconnect the
connector CN631 on the DSP 2 board.
(2) Disconnect the connector CN203 on the audio signal 1
board, and cut off the tie bands fixing the wire.
(3) Remove the two plastic rivet, and disconnect the connector
CN633, CN643 on the DSP 2 board, and disconnect
CN635 on the DSP 1 board.
(4) Remove the screw Nattaching the barrier to the shield
cover, and take out the shield cover.
Fig.12
CN25
CN234
CN208
CN45
Power/ fuse boardAudio signal 1 board
Tie bands
Tie
bands
Power 2 board
System control board Plastic rivetPlastic rivet
CN963
CN981 CN964
Shield cover
(Top view)
CN631
CN635CN643 Plastic rivet
DSP 2 board
N
CN203
CN633
Audio signal 1 board
DSP 1
board
Barrier

1-8 (No.MB177)
3.1.9 Removing the audio signal 1 board
(See Fig.13)
• Prior to performing the following procedure, remove the top
cover, side panels, stay bkt, front panel assembly and rear
panel, DSP 1 board, DSP 2 board and shield cover.
(1) From the top side of the main body, disconnect the wires
from the connectors CN202, CN204, CN234, CN224,
CN208, CN218 and CN223 on the audio signal 1 board.
(2) Remove the plastic rivet, and disconnect the connectors
CN205, CN221 and CN206 on the audio signal 1 board.
(3) Take out the audio signal 1 board.
Fig.13
3.1.10 Removing the audio signal 2 board & video board & S video board & component video board & D5 video board
(See Figs.14 and 15)
• Prior to performing the following procedure, remove the top
cover, rear panel, front panel assembly, Y/C separator board,
DSP 1 board, DSP 2 board, shield cover and audio signal 1
board.
(1) From the top side of the main body, disconnect the wire
from the connector CN324 on the audio signal 2 board.
(See fig.14)
(2) Disconnect the audio signal 2 board from the connector
CN15 and CN6 on the main board. (See fig.15)
(3) Disconnect the video board from the connector CN7 on the
main board. (See figs.14 and 15)
(4) Disconnect the S video board from the connector CN8 on
the main board. (See figs.14 and 15)
(5) Disconnect the wire from the connector CN502 on the
component video board. (See fig.14)
(6) Disconnect the component video board from the connector
CN9 on the main board. (See fig.15)
(7) Disconnect the D5 video from the connector CN10 on the
main board. (See figs.14 and 15)
Fig.14
Fig.15
Plastic rivet
CN204
CN202 Audio signal 1 board
CN205
CN221
CN206
CN234
CN224
CN208 CN223
CN218
Video board Component
video board
Audio signal 2 board
S video board
CN324
Main board
D5 video board
CN502
Main board
CN15
CN6
CN7
CN8
CN9
CN10

(No.MB177)1-9
3.1.11 Removing the main board
(See Figs.16 and 17)
• Prior to performing the following procedure, remove the top
cover, rear panel, front panel assembly, Y/C separator board,
DSP 1 board, DSP 2 board, shield cover, audio signal 1 board,
audio signal 2 board, video board, S video board, component
video board and D5 video board.
(1) From the top side of the main body, cut off the tie bands
fixing the wire. (See fig.16)
(2) Disconnect the wire from the connector CN62 on the
regulator board. (See fig.16)
(3) Disconnect the wire from the CN44 on the power 2 board .
(See fig.16)
(4) Disconnect the wire from the connector CN743 on the
speaker relay board. (See fig.17)
(5) Disconnect the card wire from the connector CN1, CN2
and the wire from the connector CN11 on the main board.
(See fig.16)
(6) Remove the seven screws Pattaching the main board, and
take out the main board. (See fig.16)
3.1.12 Removing the speaker relay board
(See Fig.17)
• Prior to performing the following procedure, remove the top
cover, side panels, stay bkt and rear panel.
(1) Disconnect the wire from the connector CN741, CN742
and CN743 on the speaker relay board. Fig.16
Fig.17
3.1.13 Removing the regulator board
(See Fig.18)
• Prior to performing the following procedure, remove the top
cover, side panels and stay bkt.
(1) From top side of the main body, disconnect the wires from
the connectors CN61, CN62, CN63, CN64 and CN65 on
the regulator board.
(2) Disconnect the wires from the connectors CN44 and CN45
on the power 2 board.
(3) Remove the six screws Qattaching the regulator board.
Reference:
When attaching the screw Q, attach the lug wire with it.
Fig.18
P
Regulator board
CN62 CN44
Power 2 board
CN2
CN743
Main board
CN1 CN11
Speaker relay board
CN743 CN742CN741
Speaker relay board
CN61
Regulator board
Q
CN45
CN44
Q
Power 2 boardCN63
CN65 CN64
CN62

1-10 (No.MB177)
3.1.14 Removing the power transformer 1 with the power 2 board
(See Fig.19)
• Prior to performing the following procedure, remove the top
cover, side panels, stay bkt and regulator board.
(1) From top side of the main body, disconnect the wire from
the connector CN46 and CN47 on the power 2 board.
(2) Remove the two screws Rattaching the power transformer
1.
3.1.15 Removing the thermal SW 1 board
(See Fig.19)
• Prior to performing the following procedure, the top cover, side
panels, stay bkt and regulator board.
(1) From top side of the main body, remove the screw S
attaching the thermal SW 1 board.
Fig.19
3.1.16 Removing the power transformer 2
(See Figs.20 and 21)
• Prior to performing the following procedure, remove the top
cover, side panels, stay bkt and regulator board.
(1) From the top side of the main body, disconnect the wire
from the connector CN701 on the power amp. board. (See
fig.20)
(2) Remove the solder points PW81 and PW82 on the power
trans 1 board. (See fig.21)
(3) Remove the four screws Tattaching the power transformer
2. (See fig.21)
Fig.20
Fig.21
S
Power 2 board
CN47 CN46
R
Power transformer 1
Thermal SW
1 board
Power amp. boardCN701
TT
PW81 PW82
Power trans 1
board
Power transformer 2

(No.MB177)1-11
3.1.17 Removing the power transformer 3 with the power 1 board
(See Fig.22)
• Prior to performing the following procedure, remove the top
cover, side panels, stay bkt, regulator board, power
transformer 1 and power transformer 2.
(1) From the top side of the main body, disconnect the wire
from the connector CN41 on the power 1 board.
(2) Remove the two screws Uattaching the power transformer
3.
Fig.22
3.1.18 Removing the power/ fuse board
(See Fig.23)
• Prior to performing the following procedure, remove the top
cover, side panels, stay bkt, rear panel, regulator board and
power transformer 2.
(1) From the top side of the main body, disconnect the wire
from the connector CN25 on the power/ fuse board.
(2) Remove the four screws Vattaching the power/ fuse board.
(3) Remove the solder from the points PW21, PW22, PW23
and PW24 on the power/ fuse board.
Fig.23
Power 1 board
CN41
U
Power transformer 3
V
V
V
PW23 (red) PW21 (blue)
PW22 (brown)
PW24 (white)
CN25
Power/ fuse board

1-12 (No.MB177)
3.1.19 Removing the head phone board
(See Figs.24 and 25)
• Prior to performing the following procedures, remove the top
cover, side panels, stay bkt and front panel assembly.
(1) From the top side of the main body, disconnect the wires
from the connector CN738 on the power amp. board. (See
fig.25)
(2) From the front side of the main body, remove the nut a
fixing the head phone board. (See fig.24)
(3) Remove the screw Wattaching the lug wire and bracket.
(See fig.24)
Reference:
When attaching the screw W, attach the lug wire with it.
Fig.24
3.1.20 Removing the power amp. assembly
(See Figs.25 and 26)
• Prior to performing the following procedures, remove the top
cover, side panels, stay bkt, rear panel, front panel assembly,
system control board, DSP 1 board, DSP 2 board, audio signal
1 board, audio signal 2 board, video board, S video board, V
compo 1 board and speaker relay board.
(1) From top side of the main body, remove the three screws
Xfixing the barriers, and remove the tow barriers. (See
fig.25)
(2) Remove the eight screws Yattaching the power amp.
assembly. (See figs.25 and 26)
(3) Take out the power amp. assembly in the direction of the
arrow. (See fig. 26)
Fig.25
Fig.26
W
Nut a
Head phone board
Lug wire Bracket
Power
amp.
assembly
Power
amp.
board
Barrier
Y
Y
CN738
X
X
Y
Power amp. assembly

(No.MB177)1-13
3.2 Power amp. assembly section
• Remove the power amp. assembly from the main body.
(See "Removing the power amp. assembly".)
3.2.1 Removing the relay board & Rch amp. board & Lch amp. board & Cch amp. board & SL/SRch amp. board
(See Figs.1 to 3)
(1) From the top side of the amp. assembly, disconnect the
wires from the two connectors on each thermal
compensation board. (See fig.1)
(2) From the bottom side of the amp. assembly, remove the
two screws Aattaching the relay board. (See fig.2)
(3) Disconnect the wires from the five connectors on each
thermal compensation board. (See fig.2)
(4) Disconecct the connectors CN712, CN713, CN812,
CN813, CN772, CN773, CN752 and CN753 on the each
amp. board of Lch, Cch, SL/SRch and Rch from the power
amp. board. (See fig.2)
(5) From the top side of the relay board, disconnect the each
amp. board from the connectors CN721, CN821, CN781
and CN761 on the relay board. (See fig.3)
Fig.1
Fig.2
Fig.3
Connectors
Thermal
compensation
board
Thermal
compensation
board
SL/SRch amp. board
Rch amp. board
Power amp. board
CN713
CN773
CN753
CN712
CN772
CN752
CN813
CN812
A
Relay board
A
ConnectorsLch amp. board
Cch amp. board
Relay board
SL/SRch amp. board
Rch amp. board
CN761CN821
CN781
Lch amp. board
Cch amp. board
CN721

1-14 (No.MB177)
3.2.2 Removing the thermal SW 2 board
(See Fig.4)
• Prior to performing the following procedure, remove the relay
board and the each amp. board of Lch, Cch, SL/SRch, Rch.
(1) From the top side of the amp. assembly, remove the screw
Battaching the thermal SW 2 board.
3.2.3 Removing the heat sink
(See Figs.4 to 6)
• Prior to performing the following procedure, remove the relay
board and the each amp. board of Lch, Cch, SL/SRch, Rch.
(1) From the both sides of the amp. assembly, remove the
eight screws Cattaching the heat sink. (See fig.4)
(2) From the top side of the amp. assembly, remove the eight
screws Dattaching the power ICs. (See fig.5)
(3) From the bottom side of the amp. assembly, remove the
twenty screws Dattaching the power ICs. (See fig.6)
Fig.4
Fig.5
Fig.6
B
Heat sink
Thermal SW 2 board
C(both sides) C(both sides)
Heat sink
D D
Heat sink
D D

(No.MB177)1-15
3.3 Front panel assembly section
• Remove the front panel assembly from the main body.
(See "Removing the front panel assembly".)
3.3.1 Removing the FL display board & front AV in board
(See Figs.1 and 2)
(1) From the front side of the front panel assembly, pull out the
volume knob to the forward and remove the nut aattaching
the FL display board. (See fig.1)
(2) From the reverse side of the front panel assembly, remove
the three screws Aattaching the front AV in board and take
out the front AV in board. (See fig.2)
(3) Remove the nine screws Battaching the FL display board.
(See fig.2)
(4) Disconnect the wires from the connectors CN969, CN975
and CN982 on the FL display board. (See fig.2)
Fig.1
Fig.2
Front panel assembly Nut a Volume knob
A
FL display board
Front AV in board
CN982 CN969 CN975
B
B

1-16 (No.MB177)
3.3.2 Removing the power switch board & front DIGITAL in board & motor assembly
(See Fig.3)
• Prior to performing the following procedure, remove the FL
display board.
(1) From the reverse side of the front panel assembly, remove
the four screws Cattaching the power switch board and
take out the power switch board.
(2) Remove the screw Dattaching the front DIGITAL in board
and take out the front DIGITAL in board.
(3) Remove the three screws Eattaching the motor assembly
on the back of the front panel assembly.
(4) Remove the belt and the two screws Fattaching the motor
assembly.
3.3.3 Removing the door input board
(See Figs.3 and 4)
• Prior to performing the following procedure, remove the FL
display board.
(1) From the reverse side of the front panel assembly, remove
the four screws Gattaching the door and take out the door
to the forward. (See fig.3)
(2) From the reverse side of the door, remove the six screws
Hattaching the door input board. (See fig.4)
Fig.3
Fig.4
F
Front DIGITAL
in board
DoorCN373
GG E
Power switch board C
D
Belt
Motor assembly
Door input board Door
H

(No.MB177)1-17
SECTION 4
ADJUSTMENT
4.1 Adjustment of idling current
Attention:
This adjustment does not obtain a correct adjustment value immediately after the amplifier is used (state that an internal temperature
has risen).
Please adjust immediately after using the amplifier after turning off the power supply of the amplifier and falling an internal temper-
ature.
Adjustment method
(1) Prior to turning the power ON, fully turn the adjusting resistor (VR701, VR702, VR751, VR752, VR771, VR772, VR801) coun-
terclockwise direction and connect the DC voltmeter to the measuring terminal (B901-B902, B903-B904, B905-B906, B907-
B908, B909-B910, B911-B912, B913-B914).
(2) Adjust the resistor so that the measured value becomes 2.0mV just after the power supply is turned on.
(3) Adjust the resistor so that the measured value becomes 2.5mV more than 60 seconds after the power supply is turned on.
(4) After stability is 1.0-4.0mV.
Refer to following page "Idling Current graph".
NOTE:
It is not abnormal though the idling current might not become 0mA even if it is finished to turn variable resistance (VR701, VR702,
VR751, VR752, VR771, VR772, VR801) in the direction of counterclockwise.
Measuring point Alignment point Measuring condition
Lch B903 & B904 VR701 No load and No signal.Rated line voltage
SURROUND : OFF
Room temperature : 20 to 25 ºC
Rch B911 & B912 VR751
Cch B907 & B908 VR801
SLch B907 & B908 VR771
SRch B909 & B910 VR772
SBLch B901 & B902 VR702
SBRch B913 & B914 VR752
B901, B902 (SBLch)
B903, B904 (Lch)
B905, B906 (SLch)
B907, B908 (Cch)
B909, B910 (SRch)
B911, B912 (Rch)
B913, B914 (SBRch)
VR701 (Lch)
VR801 (Cch)
VR771 (SLch)
VR702 (SBLch)
VR772 (SRch)
VR752 (SBRch)
VR751 (Rch)

1-18 (No.MB177)
4.2 Idling Current graph (1/2)
SL ch / SR ch
0
0.5
1
1.5
2
2.5
3
3.5
4
Time(Min)
Voltage at measering point(mV)
SL ch
SR ch
SBL ch / SBR ch
0
0.5
1
1.5
2
2.5
3
3.5
4
0 8 10 12 14
Time(Min)
SBL ch
SBR ch
Voltage at measering point(mV)
642
0 8 10 12 14642

(No.MB177)1-19
4.3 Idling Current graph (2/2)
L ch / R ch
0
0.5
1
1.5
2
2.5
3
3.5
4
Time(Min)
Voltage at measering point(mV)
L ch
R ch
C ch
0
0.5
1
1.5
2
2.5
3
3.5
4
Time(Min)
Voltage at measering point(mV)
0 8 10 12 14642
0 8 10 12 14642

1-20 (No.MB177)
SECTION 5
TROUBLESHOOTING
This service manual does not describe TROUBLESHOOTING.