JVC RX-8030VBK Service Manual
SERVICE MANUAL
CONTR OL
AUDIO/VIDEO CONTROL RECEIVER
2207120036
RX-8030VBK
Area suffix
J ----------------------------- U.S.A.
C -------------------------- Canada
A/V CONTROL RECEIVER
231
MENU
564
ENTER
7/P
89
+10
10/0
0
TABLE OF CONTENTS
1 Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-4
2 Disassembly method . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-6
3 Adjustment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-14
4 Description of major ICs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-16
COPYRIGHT © 2003 VICTOR COMPANY OF JAPAN, LIMITED
No.22071
2003/6
Amplifier Output Power
Audio Input Sensitivity/Impedance
(1 kHz)
Audio Input (DIGITAL IN)*
Audio Output Level PRE OUT : 1 V
Recording Output Level VCR 1 OUT, VCR 2 OUT, CDR OUT, TAPE/MD OUT : 200 mV
Digital output Optical : DIGITAL OUTPUT
Signal wave length 660 nm
Audio
Output level -21 dBm to -15 dBm
Signal-to-Noise Ratio ('66 IHF/'78 IHF)
PHONO IN 70 dB/78 dB (at REC OUT)
DVD IN, VCR 1 IN, VCR 2 IN, TV
SOUND/DBS IN, VIDEO
CD IN, CDR IN, TAPE/MD IN 87 dB/80 dB
Frequency Response (8Ω)
SPECIFICATION
130 W per channel, min. RMS, driven into
At Stereo operation Front ch
Front ch
Center ch
At Surround
operation
Surround ch
Surround Back ch
PHONO IN (MM) 2.5 mV/47 kΩ
DVD IN, VCR 1 IN, VCR 2 IN, TV
SOUND/DBS IN, VIDEO IN
CD IN, CDR IN, TAPE/MD IN 200 mV/47 kΩ
Coaxial DIGITAL 1 (DVD) : 0.5 V(p-p)/75 Ω
Optical
87 dB/80 dB
PHONO IN 20 Hz to 20 kHz (±1 dB)
DVD IN, VCR 1 IN, VCR 2 IN, TV
SOUND/DBS IN, VIDEO
CD IN, CDR IN, TAPE/MD IN 20 Hz to 100 kHz (+1 dB, -3 dB)
RIAA Phono Equalization ±1.0 dB (20 Hz to 20 kHz)
Equalization (5 bands) 63 Hz, 250 Hz, 1 kHz, 4 kHz, 16 kHz (±8 dB)
Bass boost +6 dB ±1.0 dB at 100 Hz
DIGITAL 2 (CD), DIGITAL 3 (TV), DIGITAL 4 (CDR) :
-21 dBm to -15 dBm (660 nm ±30 nm)
8Ω, 20 Hz to 20 kHz, with no more than
0.08% total harmonic distortion.
130 W per channel, min. RMS, driven into
8Ω at 1 kHz, with no more than 0.8% total
harmonic distortion.
130 W, min. RMS, driven into 8Ω at 1 kHz,
with no more than 0.8% total harmonic
distortion.
130 W per channel, min. RMS, driven into
8Ω at 1 kHz, with no more than 0.8% total
harmonic distortion.
130 W, min. RMS, driven into 8Ω at 1 kHz,
with no more than 0.8% total harmonic
distortion.
200 mV/47 kΩ
20 Hz to 100 kHz (+1 dB, -3 dB)
1-2 (No.22071)
Composite video
Video Input Sensitivity/Impedance
Video
Video Output Level
Tuning Range 87.5 MHz to 108.0 MHz
FM tuner
(IHF)
AM tuner Tuning Range 530 kHz to 1 710 kHz
General
* Corresponding to Linear PCM, Dolby Digital, and DTS Digital Surround (with sampling frequency - 32 kHz, 44.1 kHz, 48 kHz).
Designs & specifications are subject to change without notice
Usable Sensitivity Monaural 12.8 dBf (1.2 µV/75 Ω)
50 dB Quieting Sensitivity Monaural 16.0 dBf (1.7 µV/75 Ω)
Stereo 37.5 dBf (20.5 µV/75 Ω)
Stereo Separation at REC OUT 35 dB at 1 kHz
Power Requirements AC 120V~, 60 Hz
Power Consumption 320 W/440 VA (at operation) 2 W (in standby mode)
Dimensions (W × H × D) 435 mm × 157 mm × 425 mm (17 3/16 in. × 6 3/16 in. × 16 3/4 in.)
Mass 12.2 kg (27.0 lbs)
S-video
Component video
Composite video
S-video
Component video MONITOR OUT
Synchronization Negative
Signal-to-Noise Ratio 45 dB
DVD IN, VCR 1 IN, VCR 2 IN, TV
SOUND/DBS IN, VIDEO
(Y: luminance): 1 V(p-p)/75 Ω
(C: chrominance,
burst):
(Y: luminance): 1 V(p-p)/75 Ω
(PB/PR): 0.7 V(p-p)/75 Ω
VCR 1 OUT, VCR 2 OUT, MONITOR
OUT
VCR 1 OUT, VCR
2 OUT,
MONITOR OUT
(Y: luminance) 1 V(p-p)/75 Ω
(C: chrominance,
burst)
(Y: luminance) 1 V(p-p)/75 Ω
(PB/PR) 0.7 V(p-p)/75 Ω
1 V(p-p)/75 Ω
0.286 V(p-p)/75 Ω
1 V(p-p)/75 Ω
0.286 V(p-p)/75 Ω
(No.22071)1-3
SECTION 1
Good earth ground
d
AC VOLTMETER
Precautions
1.1 Safety Precautions
(1) This design of this product contain s special hardware and
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. Services should be performed by qualified personnel only.
(2) Alterations o f the design or circuitry of the product sh ould
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 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 the Service Manual. The use of a substitute
replacement which does not have the same safety characteristics 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 origin al lead routing
and dress should be observed, and it should be confirmed
that they have been returned to normal, after reassembling.
(5) Leakage shock hazard testing
After reassembling the product, always perform an isolation check on the exposed metal parts of the product (antenna 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, particularly any exposed metal part having a return path to the
chassis, to a known good earth ground. Any leakage current 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, 1,000Ω per volt or more sensitivity
in the following manner. Connect a 1,500Ω 10W resistor
paralleled by a 0.15µF AC-type capacitor between an exposed metal part and a known good earth ground.
Measure the AC voltage across the resistor with the AC
1-4 (No.22071)
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 0.5µ
mA AC (r.m.s.).
(Having 1000
ohms/volts,
or more sensitivity)
0.15 F AC TYPE
Place this
probe on
1500 10W
1.2 Warning
(1) This equipment has been designed and manufactured to
meet international safety standards.
(2) It is the legal respo nsibility 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 e ssential that safety critical components ar e 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 preforming 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)
each expose
metal part.
1.5 Importance administering poin on the safety
Primary part
F 1
6.3A-125V
Secondary parts
F 62
F 61
2A-125V
2A-125V
Caution: For continued protection against risk of
fire, replace only with same type 6.3A/125V for
F1, 2A/125V for F61 and F62.
This symbol specifies type of fast operating fuse.
Precaution: Pour eviter risques de feux, remplacez
le fusible de surete de F1 comme le meme type
que 6.3A/125V, et 2A/125V pour F61 et F62.
Ce sont des fusibles suretes qui functionnes rapide.
^
(No.22071)1-5
SECTION 2
f
1
Disassembly method
2.1 Removing the top cover (See Fig.1)
(1) From the right and left sides of th e main body, remove the
four screws A attaching the top cover.
(2) From the back side of the main body, remove the three
screws B attaching the top cover.
(3) Remov e the to p cover in the di recti on of th e arrow 2 w hile
extending the lower sections of the top cover in the direction of the arrow 1.
2.2 Removing the rear panel (See Fig.2)
• Prior to performing the following procedures, remove the top
cover.
(1) From the back side of the main body, remove the strain re-
lief from the rear panel in the direction of the arrow.
(2) Remove the thirty-four screws C, two screws D and three
screws E attaching the rear panel.
Top cover
C
E
A
C
2
B
A
1
1
Fig.1
D
C
Strain relie
E
2.3 Removing the I/O board (See Fig.3)
• Prior to performing the following procedures, remove the top
cover and rear panel.
(1) From the top side of the main body, remove the two plastic
rivets in the direction of the arrow 1.and remove the stopper boards in the direction of the arrow 2.
(2) Remove the tie bands bundling the wires.
(3) Disconnect the wire from the connector CN722 on the cen-
ter board.
(4) Disconnect the wire from the connector CN714 on the front
board (L).
(5) Disconnect the wire from the connector CN717 on the sur-
round back board.
(6) Disconnect the wire from the connector CN719 on the front
board (R).
Disconnect the wire from the connector CN723 on the main
board.
(7) Disconnect the connectors (CN205, CN361, CN381,
CN501) on the I/O board in an upward direction.
Front board(R)
CN719
Main board
CN723
CN381
CN501
Plastic rivet
Stopper board
CN361
CN205
Rear panel
Surround board
CN717 CN714
2
2
1
1
Stopper board
EC
Fig.2
Front board(L)
2
2
1
1
Plastic rivet
Fig.3
C
Center board
Tie band
CN722
Tie bands
I/O board
1-6 (No.22071)
2.4 Removing the front panel assembly (See Fig.4 and Fig.5)
• Prior to performing the following procedures, remove the top
cover, rear panel and I/O board.
(1) From the top side of the main bod y, remove the tie bands
bundling the wires. (See Fig.4)
(2) Disconnect the wire from the connector CN599 on the DSP
board. (See Fig.4)
(3) Disconnect the wire from the connector CN415 on the
Audio2 board. (See Fig.4)
(4) Disconnect the wire from the connector CN206 on the Vid-
eo board. (See Fig.4)
(5) Disconnect th e wire from the connector CN244 on the S-
Video board. (See Fig.4)
(6) Disconnect the card wire from connector CN402 on the
power supply board. (See Fig.4)
(7) Disconnect the card wire from connector CN400 on the mi-
con board. (See Fig.4)
(8) Remove the tie band and wire protection board fixing the
card wire. (See Fig.4)
(9) Remove the three screws F and screw G attaching the front
panel assembly. (See Fig.4)
REFERENCE :
When attaching the screw G, attach the earth wire with it.
(10) From the bottom side of the main body, remove the four
screws H attaching the front panel assembly. (See Fig.5)
(11) Remove the front panel assembly in the direction of the ar-
row. (See Fig.5)
Wire
protection
board
Tie band
Card wire
Tie band
CN400
DSP board
CN599
CN415
Audio2 board
Front panel assembly
F
CN206
Video board
FFG
Fig.4
Front panel assembly
Card wire
Tie band
CN402
Power supply
board
Tie band
Micon board
CN244
S-Video board
HH
Fig.5
(No.22071)1-7
2.5 Removing the tuner, DSP board, Audio board, Audio2 board, Video board and S-Video board (See Fig.6)
• Prior to performing the following procedures, remove the top
cover, rear panel and I/O board.
(1) From the top side of the main body, remove the tie band
bundling the wire.
(2) Disconnect the card wire from connector CN314 on the Au-
dio board, and take out the tuner.
(3) Disconnect the wire from the connector CN599 on the DSP
board.
(4) Disconnect the DSP board from the connector CN601 on
the micon board.
(5) Disconnect the wire from the connector CN415 on the
Audio2 board.
(6) Disconnect the Audio2 board from the connector CN301 on
the micon board.
(7) Disconnect the Audio board from the connectors (CN101,
CN303) on the micon board.
(8) Disconnect the wire from the connector CN206 on the Vid-
eo board.
(9) Disconnect the Video board from the connector CN201 on
the micon board.
(10) Di sconnect the wire from the connector CN244 on the S-
Video board.
(11) Di sconnect the S-Video board from the connector CN241
on the micon board.
CN314
Tie band
CN303
CN101
CN415
DSP board
CN601
CN599
CN301
Audio2 board
Card wire
Video board
Audio board
CN206
S-video board
Fig.6
CN201
CN244
Tuner
Micon board
CN241
2.6 Removing the micon board (See Fig.7)
• Prior to performing the following procedures, remove the top
cover, rear panel, I/O board, tuner, DSP board, Audio board,
Audio2 board, Video board and S-Video board.
(1) From the top sid e of the main body, disconnect the card
wire from the connector CN400 on the micon board.
(2) Disconne ct the relay board from the connector CN81 on
the micon board.
(3) Disconne ct the parallel wire from the connectors CN931
and CN932 on the micon board.
(4) Disconne ct the paral lel wire from the conn ector CN83 1 on
the main board.
(5) Remove the two screws J and screw J' attaching the micon
board.
REFERENCE :
When attaching the screw J', attach the earth wire with it.
(6) Remove the three screws K attaching the transistors
(Q921, Q931, Q941) to the chassis base.
(7) Loosen the screw L attaching the micon board.
Card wire
J
CN400
J
Micon board
Transistors
(Q921,Q931,Q941)
K
CN831
CN931
J
Fig.7
Main board
Relay board
L
Chassis base
CN81
CN932
1-8 (No.22071)
2.7 Removing the speaker board
r
(See Fig.8)
• Prior to performing the following procedures, remove the top
cover, rear panel.
(1) From the top side of the main body, remove the tie band
bundling the wires.
(2) Disconnect the wires from the connectors (CN813, CN814)
on the main board.
(3) Disconnect the parallel wire fro m the connectors (CN931,
CN932) on the micon board.
(4) Remove the screw J' attaching the micon board.
(5) Take out the speaker board in the direction of the arrow.
Micon board
Main board
Tie band
CN931
CN932
2.8 Removing the main board (See Fig.9)
• Prior to performing the following procedures, remove the top
cover.
(1) From the top side of the main bod y, remove the tie bands
bundling the card wire and wires.
(2) Remove the tie band and wire protection board bundling
the card wire.
(3) Disconnect the wire from the connector CN811 on the pow-
er transformer board 1.
(4) Disconnect the relay board from the connector (CN71,
CN81) on the power supply board and micon board.
(5) Disconnect the parallel wire fro m the connectors (CN831,
CN881) on the main board.
(6) Disconnect the wire from the connectors (CN72 3, CN813,
CN814) on the main board.
(7) Disconnect the wire from the connector CN722 on the cen-
ter board.
(8) Disconnect the wire from the connector CN714 on the front
board (L).
(9) Disconnect the wire from the connector CN717 on the sur-
round back board.
(10) Disconnect the wire from the connector CN719 on the front
board (R).
(11) Remove the screw L, six screws M and two screws N at-
taching the main board.
(12) Take out the main board.
CN814
Front board(R)
M
Tie band
Wire
protection
board
M
Card wire
N
Main board
Tie band
CN723
CN814
Micon board
CN813
Surround board
CN881
CN717
CN719
CN831
CN813
J
Fig.8
Front board(L)
Tie band
N
CN714
Fig.9
Speaker board
Center board
M
CN722
CN71
CN811
Power
supply
board
Power
transforme
board 1
Tie bands
Relay board
L
CN81
(No.22071)1-9
2.9 Removing the heat sink (See Fig.10 and 11)
• Prior to performing the following procedures, remove the top
cover and main board.
(1) From the reverse side of the main board , remove the two
screws P attaching the main board to the heat sink. (See
Fig.10)
(2) Disconnect the connector (CN701-CN706) on the main
board, remove the main board. (See Fig.10)
(3) Remove the twelve screws Q attaching the heat sink. (See
Fig.11)
2.10 Removing the center board, front boards (L/R), surround boards (L/R) and surround back board (See Fig.10 and Fig.12)
• Prior to performing the following procedures, remove the top
cover and main board.
(1) From the reverse side of the main board , remove the two
screws P attaching the main board to the heat sink. (See
Fig.10)
(2) Disconnect the connectors (CN701-CN706) on the main
board, remove the main board. (See Fig.10)
(3) Remove the two screws Q attaching the center board. (See
Fig.12)
(4) Remove the two screws Q attaching the front board (L).
(See Fig.12)
(5) emove the two screws Q attaching the surround back
board. (See Fig.12)
(6) Remov e the two screws Q attaching the front board (R).
(See Fig.12)
(7) Remov e the two screws Q attaching the surround board
(L). (See Fig.12)
(8) Remov e the two screws Q attaching the surround board
(R). (See Fig.12)
P
CN703
Heat sink
Heat sink
CN701
CN704
CN702
Fig.10
Fig.11
Main board
P
CN706
CN705
Q
Q
Front board(R)
Q Q Q Q Q Q
Surround board(R)
Front board(L)
Surround back board
Surround board(L)
Fig.12
Center board
1-10 (No.22071)
2.11 Removing the power transformer
r
r
(See Fig.13)
• Prior to performing the following procedures, remove the top
cover.
(1) From the top side of the main body, remove the tie band
bundling the wires.
(2) Disconnect the wire from the connectors (CN5 5, CN811)
on the power transformer board 1.
(3) Remove the solders from the solder ed sections a on the
power transformer board 2.
(4) Remove the four screws R attaching the powe r tra nsfor m-
er.
2.12 Removing the power/fuse board
(See Fig.13)
• Prior to performing the following procedures, remove the top
cover.
(1) From the back side and top side of the main body, remove
the tie band from the bundling the wires and the power
cord.
(2) Remove the screws S and scre w T attaching the power/
fuse board.
(3) Remove the solders from the soldered sections b attaching
the power cord.
(4) From the reverse side of the power/fuse board, remove the
solders from the soldered sections c attaching the wires.
Tie band
Power transformer
board 2
Soldered
sections a
Soldered
sections c
Power/fuse
board
Fig.13
CN811
S
CN55
Power transforme
board 1
Power transforme
RR
Tie band
T
Tie band
Soldered
sections b
Power cord
(No.22071)1-11
2.13 Removing the power surly board
r
(See Fig.14)
• Prior to performing the following procedures, remove the top
cover.
(1) From the top side of the main body, disconnect the parallel
wire from the connector CN55 on the power transformer
board 1.
(2) Disconnect the card wire from the connector CN402 on the
power supply board.
(3) Disconne ct the relay board from the connector CN71 on
the power supply board.
(4) Remove the three screws U attaching the power supply
board.
(5) Remo ve the power supply board from the hook d of the
chassis base bracket in the direction of the arrow, and take
out the power supply board.
(6) Turn over the power supply board, and remove the solders
from the soldered sections e attaching the wire.
2.14 Removing the headphone jack board
(See Fig.14 and Fig.15)
• Prior to performing the following procedures, remove the top
cover, rear panel, I/O board and front panel assembly.
(1) From the top side of the main body, disconnect the parallel
wire from the connector CN881 on the main board. (See
Fig.14)
(2) From the fro nt side of the main body, remove the nut and
screw V attaching the headphone bracket to the front
bracket. (See Fig.15)
(3) Remove the three screws U attaching the power supply
board. (See Fig.14)
(4) Take out the headphone jack board from the inside of the
chassis base while lifting the power supply board.
U
CN402
CN71
CN881
Main board
Main board
Tie band
Relay board
Hook (d) of the chassis
base bracket
Nut
Card wire
Fig.14
V
Power supply board
CN55
Headphone jack board
Headphone
jack board
Soldered
sections e
Power transforme
board 1
U
U
2.15 Removing the switch board
(See Fig.16)
• Prior to performing the following procedures, remove the top
cover, rear panel, I/O board and front panel assembly.
(1) From the back side of the front panel assembly, remove the
two screws W attaching the switch board.
(2) Take out the switch board, disco nnect the wire from the
connector CN432 on the switch board.
2.16 Removing the power switch board
(See Fig.16)
• Prior to performing the following procedures, remove the top
cover, rear panel, I/O board and front panel assembly.
(1) From the back side of the front panel assembly, remove the
two screws X attaching the power switch board.
(2) Take out the power switch board, disconnect the wire from
the connector CN430 on the power switch board.
Headphone bracket
W
CN432
W
Switch board
Fig.15
Front panel assembly
Front video board
Fig.16
Front bracket
CN430
X
Power switch board
1-12 (No.22071)
2.17 Removing the front key & system control board, front video board
Y
(See Fig.17 to Fig.20)
• Prior to performing the following procedures, remove the top
cover, rear panel, I/O board, front panel assembly, switch
board and power switch board.
(1) From the front side of the front panel assembly, pull out the
volume and jog knobs, and remove the nut attaching the
front key & system control board. (See Fig.117)
(2) From the back side of the front panel assembly, remove the
eight screws Y attaching the sub panel assembly. (See
Fig.18)
(3) Remove th e wires of the front video board from the ho ok f
of the front panel assembly in the direction of the arrow 1.
(See Fig.18)
(4) Remove the sub panel assembly while releasing the claws
g in the direction of the arrow 2. (See Fig.18 and Fig.19)
(5) From the front side of the front panel assembly, disconnect
the wire from the connector CN412 on the front key & system control board, and take out the front video board. (See
Fig.20)
(6) Remove the claws h attaching the front key & system con-
trol board in the direction of the arrow and take out the front
key & system control board. (See Fig.20)
Front panel assembly
Jog knob
Y
Volume knob
Nut
Fig.17
Front panel assembly
1
2
2
Claws g Claws g Claws g
Front video board
Sub panel assembly
Front key & System control board
2
Sub panel assembly
Fig.18
Fig.19
Front panel assembly
2
Front panel assembly
Hook f
CN412
Claws hClaws h
Fig.20
Front video board
(No.22071)1-13
SECTION 3
Adjustment
3.1 Adjustment method Tuner section
1. Tuner range
FM 87.5MHz to 108.0MHz
AM 530kHz to 1710kHz
Power amplifier section
Adjustment of idling current
Measurement location B2204-B2205 (Lch), B2213-B2214 (Rch)
Adjustment part VR787 (Lch), VR788 (Rch)
Attention:
This adjustment does not obtain a correct adju stment value i mmediately after the amplifier is used (state that an in ternal temperature has risen). Please adjust immediately after using the amplifier after turning off the power supply of
the amplifier and falling an internal temperature.
<Adjustment method>
(1) Set the vo lume control to minimum during this adjustment. (No signal & No load)
(2) Set the surround mode OFF.
(3) Turn VR787 and VR788 fully counterclockwise to warm up before adjustment.
If the heat sink is already warm from previous use the correct adjustment can not be made.
(4) For L-ch, connect a DC voltmeter between B2204 and B2205 (Lch) and, connect it between B2213 and B2214 (Rch).
(5) 30 minutes later after power on, adjust VR787 for Lch, or VR788 for Rch so that the DC voltmeter value has 1mV to 10mV.
• It is not abnormal though the idling current might not b ecome 0mA even if it is fin ished to turn variable re sistance (VR787,
VR788) in the direction of counterclockwise.
Front board (L)
VR787
B2204
B2205
Front board (R)
VR788
B2213
B2214
VR787 (Lch)
B2204, B2205 (Lch)
VR788 (Rch)
B2213, B2214 (Rch)
1-14 (No.22071)
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