Nakamichi BX-2 User manual

Nakamichi
Service
Manual
Nakamichi
BX-2
2
Head
Cassette
Deck
Pn BCP sme

CONTENTS
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1, GENERAL
1.1. Voltage Selector
Voltage selector is installed on the rear panel for Other version of the Nakamichi BX-2.
This voltage selector can select either 120 V or 220-240 V at customer’s disposal.
1.2, Parts List for Carton and Packing
Part No. Description Q’ty
OF 03673C Carton 1
OFO3674A Packing 2
1.3. Serial Number
The BX-2 has two versions, Silver and Black.
In the service manual, serial numbers of these versions are identified as follows:
Silver version: A316xxxxx
Black version: A317xxxxx
However,
the
actual
serial
number
on
the
serial
number
plate
of
the
BX-2
is
indicated
as
A316.7xxxxx.
The serial number begins with A316.701001.

2.
MECHANICAL
ADJUSTMENTS
2.1.
Tape
Guide
Height
Check
for
Record/Playback
Head
and
Erase
Head
.
With
use
of
an
M-300
produced
by
Information
Terminals,
tape
guide
height
check
for
the
Record/Playback
and
Erase
Heads
shall
be
made,
wherein
a
small
block
shall
be
pushed
straight
down
to
the
base
while
in
use
of
the
M-300,
Refer
to
Fig,
2.1.
(1) Record/Playback Head Tape Guide Height
(a)
Load
the
base
of
the
M-300
carefully,
then
set
the
cassette
deck
in
Play
mode.
(b)
Place
the
small
block
of
the
M-300
on
the
base.
(ce)
Slide
the
small
block
against
the
tape
guide
of
the
Record/
Playback
Head,
and
check
to
insure
that
the
block
is
ac-
cepted
by
the
tape
guide.
(ad)
If
not,
loosen
the
screw
and
insert
a
shim
(either
30
um
(0C80048A),
60
um
(0C80038A),
or
100
hm
(0C80039A))
to
raise
the
Record/Playback
Head,
then
tighten
and
apply
a
quantity
of
lock
tight
paint
to
the
screw.
(2) Erase Head Tape Guide Height
(a)
Load
the
base
of
the
M-300
carefully,
then
set
the
cassette
deck
in
Play
mode.
(b)
Place
the
small
block
of
the
M-300
on
the
base.
(ce)
Slide
the
small
block
against
the
tape
guide
of
the
Erase
Head,
and
check
whether
the
block
is
accepted
by
the
tape
guide.
2.2. Head Base Stroke Check
Refer to Fig, 2.2.
(1)
Load
the
base
of
the
M-300
carefully,
then
push
the
base
toward
the
Record/Playback
Head
to
eliminate
the
clearance
between
the
reference
pin
and
the
base.
(2) Set the cassette deck in Play mode,
(3)
Place
the
small
block
of
the
M-300
on
the
base,
(4)
Contact
the
small
block
with
the
Record/Playback
Head
sur-
face
and
the
Erase
Head
surface,
and
check
whether
the
end
of
the
small
block
is
located
within
the
specified
tolerance
as
shown
in
the
figure.
2.3.
Record/Playback
Azimuth
Alignment
and
Height
Check
Refer to Fig. 2.1.
(1) Connect a VTVM to the Output Jacks,
(2)
Load
a
15
kHz
Azimuth
Tape
(DA09004A),
then
set
the
cassette
deck
in
Play
mode.
(3)
Turn
the
Azimuth
Alignment
Screw
until
the
outputs
of
both
channels
become
maximum.
(4)
Load
al
kHz
Track
Alignment
Tape
(DA09007A),
then
set
the
cassette
deck
in
Play
mode.
(5)
Check
to
insure
that
the
readings
of
both
channels
on
the
VTVM
are
below
—25
dB.
If
not,
replacement
of
the
Record/Playback
Head
will
be
required,
<
(6)
Apply
a
quantity
of
lock
tight
paint
to
the
Azimuth
Align-
ment
Screw,
2.4,
Pressure
Adjustment
of
Pressure
Roller
Refer to Fig, 2.3.
(1)
In
Play
mode,
measure
the
torque
of
the
Pressure
Roller
and
check
whether
the
torque
is
in
a
range
of
320
+50
g-cm.
(2)
If
torque
is
out
of
the
range,
correct
it
by
changing
the
instal-
lation
point
of
the
Pressure
Roller
Spring.
2.5. Tape Travelling Check
Load
the
Tape
Travelling
Cassette
(DA09027A),
then
set
the
cassette
deck
in
Play
mode
and
check
the
following:
(1)
After
more
than
2
seconds,
the
fluctuation
of
the
tape
trav-
elling
on
the
Record/Play
back
Head
is
small,
(2)
Tape
isin
contact
with
the
head
sufficiently.
(3)
Tape
waving
is
small
on
the
heads
and
pressure
roller.
2.6. Eject Damper Adjustment
Refer
to
Fig.
2.4.
Load
a
cassette
tape,
and
with
opening
the
Cassette
Case
by
pressing
the
Eject
button
and
closing
it
by
hand,
adjust
the
speed
of
damper
movement
by
the
Adjustment
Screw.
CCW: Damper moves fast.
CW: Damper moves slowly.
Fig, 2.3
Decrease NH
Increase
Capstan Motor
Fig, 2.4

2.7, Reel Motor Speed Adjustment in Play Mode
(1) Connect a DC Voltmeter across the Reel Motor terminals.
(2) Load a C-60 cassette tape, then set the cassette deck in Play
mode,
(3) Adjust VR601 on the Main P.C.B. Ass’y to obtain approx. 3
V on the DC Voltmeter at the beginning of the tape.
(4) Load a Torque Meter TW-2111 (Made by Sony) and check
that the torque is 50 +10 g-cm.
2.8. Tape Speed Adjustment
Refer to Fig. 2.5,
(1) Connect a frequency counter to the Output Jacks,
(2)
Load
a
3
kHz
Speed
and
Wow/Flutter
Tape
(DA09006B)
and
Play
it back.
(3)
Adjust
the
Tape
Speed
Adjustment
Volume
incorporated
in
the
Capstan
Motor
to
obtain
3,000
Hz
on
the
frequency
counter,
CCW: Motor drives slowly.
CW: Motor drives fast.
2.9. Lubrication
The
tape
transport
is
of
a
lubrication-free
type
mechanism.
When
the
following
parts
are
replaced,
apply
the
specified
lubricant.
(1) Molykote®) Grease (X5-6020)
Cam Motor Pulley
Thrust portion on the Capstan Shaft
(2) FLOIL GB-TS-1
Washer
between
Reel
Hub
Ass’y
and
Back
Tension
Spring
(3)
Diamond
Oil
(EP56)
Reel Hub Shaft
(4) Anderol 456
Capstan Shaft
Note: We suggest that you use the above specified lubricant or
3. PARTS LOCATION FOR ELECTRICAL ADJUSTMENT
T301
@ | Bias osc.
Frequency
@ Lvei0e
Bios Cut @ fvreve
VR6OI
Reel Motor Speed (Play)
©TPior
TP201
©
MPX Filter
L205
Fig. 3
Playbock Level
Meter Level
G@ tveeo1
equivalent type.
The company dealing in the above lubricant is as follows:
(a) Molykote() Grease (X5-6020)
Dowcorning Co., Ltd., 1-15-1 Nishishinbashi, Minato-
ku, Tokyo, Japan
(b) FLOIL GB-TS-1
Kanto Chemicals Co., Ltd., 2-7 Kanda Sakuma-cho,
Chiyoda-ku, Tokyo, Japan
(c) Diamond Oil (EP-56)
Mitsubishi Oil Co., Ltd., 1-2-4 Toranomon, Minato-ku,
Tokyo, Japan
(d) Anderol 456
Toyo Kokusai Oil Co., Ltd., 3-3-5 Hatchobori, Chuo-
ku, Tokyo, Japan
‘6
Increase
Domper Adjustment
Screw
Bios Trop
Peaking — (Record)
L203(@)
-200(@) ©
TP203
Rec. Cal.
VR204 VR203 VR202
‘ll VRIO5
VR207 VR206 VR205
02
N Pad
zx
SX
m ~
7)
x
VRIO4 VRIO3 VRI
sce
EX
LIO5

4.
ELECTRICAL
ADJUSTMENTS
AND
MEASUREMENTS
Note:
Electrical
adjustment
should
be
performed
after
mechanical
adjustment
is
completed.
4,1,
Adjustment
and
Measurement
Instructions
SIGNAL OUTPUT
EEN SOURCE
CONNECTION
ADJUST-
MENT
REMARKS
3 kHz Speed
and Frequency
Tape Speed | wow/Flutter | Counter to
Adjustment | Tape Output Jacks
(DA09006B)
Playback
Eq. SW— 70 us
Tape Speed
Adjustment
Volume
Adjust
the
volume
incorporated
in
the
capstan
motor
to
obtain
3
kHz
+0.5%
on
the
frequency
counter,
VTVM to
TP101, TP201
on Main P.C.B.
400 Hz to
Input Jacks
Meter Level
Calibration
Record, Pause
Main P.C.B.
VR108,VR208
1.
Feed
in
400
Hz,
then
adjust
the
Input
Level
control
to
obtain
350
mV
—0.9
dB
on
the
VTVM.
2.
Adjust
VR108
(VR208)
so
that
the
0
dB
segment
of
the
level
meter
starts
iluminat-
ing.
3.
Adjust
the
Input
Level
control
to
obtain
350
mV
on
the
VTVM,
then
decrease
the
generator
output
level
by
20
dB.
4,
Check
to
insure
that
the
segment
for
—20
dB
illuminates,
MPX Filter | 19 ¥Hz seo VTVM to
Record, Pause
MPX SW — OFF/ON
Main P.C.B.
L105,L205
1,
Adjust
the
Input
Level
control
to
obtain
0
dB
(500
mV)
on
the
VTVM.
2.
Set
the
MPX
Filter
switch
to
ON,
then
adjust
L105
(L205)
to
obtain
minimum
reading
on
the
VTVM
(minimum
reading
will be less than —30 dB).
Playback
Eq. SW — 70 us
MPX SW — OFF
Dolby NR SW — OFF
Record/Pliay back
Head Azimuth
Alignment
Screw
Adjust
the
Record/Playback
Head
Azimuth
Alignment
Screw
to
obtain
maximum
readings
of
both
channels
on
the
VT
VM.
' Hz to
Adjustment Input Jacks Output Jacks
Record/ 4
Playback 15 kHz
4 | Head Azimuth Tape | Gorout Jacks
Azimuth (DA09004A)
Alignment
Playback 400 Hz Level VTVM to
5
Level
Tape
TP101,
TP201
Calibration | (DA09005A) on Main P.C.B.
a aa
Same as above
Main P.C.B.
VR101,VR201
Adjust
VR101
(VR201)
to
obtain
350
mV
on
the
VTVM.
————_—__--}
400 Hz Level
Tape
(DAO09005A)
10 kHz PB
Frequency
Response Tape
(DA09003A)
15 kHz PB
Frequency
Response Tape
(DA09002A)
20 kHz PB
Frequency
Response Tape
(DA09001A)
Playback
Frequency
6 | Response
Adjustment
VTVM to
Output Jacks
Playback
Eq. SW — 70 ys ;
Dolby NR SW — OFF
MPX SW — OFF
1,
Load
a
400
Hz
level
tape
and
play
it
back.
2.
Load
10
kHz,
15
kHz
and
20
kHz
PB
fre-
quency
response
tapes
and
adjust
the
record/playback
head
azimuth
to
obtain
maximum
levels
on
the
VTVM
with
each
tape.
3.
Read
the
maximum
levels
with
each
tape
and
check
to
insure
that
the
levels
against
the
400
Hz
level
tape
are
within
the
follow-
ing
ranges,
10 kHz (—20 dB) —2 dB to +2 dB
15 kHz (—20 dB) —2 dB to+3 4B
20 kHz (—20 dB) —2 dB to +4 dB
Check
to
insure
that
the
difference
in
level
between
10
kHz
(20
dB)
and
20
kHz
(—20
dB)
is
less
than
2
dB.
Note:
If
the
playback
level
of
20
kHz
PB
frequency
response
tape
is
insuf-
ficient,
add
C107
(C207)
150
pF
in
parallel
with
C108
(C208)
1200
pF
in
the
playback
eq.
amp.
circuit
of
the
Main
P.C.B.
Ass’y.
4,
Conduct
step
4
“Record/Playback
Head
Azimuth Alignment’’.
Frequency
Bias
Counter
to
Oscillation
TP102
7
Frequency
on
Main
P.C.B.
and
Erase
and
Current
VTVM
across
Adjustment
the
additional
0.1 Q resistor
Record, Pause
Tape SW — ZX
Eq. SW — 70 us
Dolby NR SW — OFF
MPX SW — OFF
Main P.C.B.
T301
R318,R350
i,
Adjust
T301
to
obtain
105
kHz
on
the
fre-
quency
counter.
2.
Connect
an
additional
0.1
Q
resistor
in
series
to
the
Erase
Head,
then
connect
a
VTVM
across
it.
3. Check the erase current by the VT'VM,
Erase
current
will
be
in
a
range
of
145
mA
to
185
mA
(typically
approx.
165
mA).
If
erase
current
is
not
sufficient,
increase
it
by
shorting
R318
or
R350.
4,
After
completion
of
the
erase
curent
ad-
justment,
re-check
the
bias
oscillatiora
fre-
quency,
Remove the additional 0.1 2 resistor,
5.
|
1.
|
ceapure.
[ol
EBe
VTVM
to
re
8
;
(—20
dB)
to
TP102,
TP202
ain
P.C.B.
2s
Equalizer
Same
as
above
L102,L202
3
Short
both
Bias
Stop
test
pins
with
a
clip
to
stop
the
bias
oscillation.
Adjust
L102
(L202)
to
obtain
peak
read-
ing
at
21
kHz
on
the
VTVM.
. Remove the clip from the test pins.
Bias Trap
9
|
Adjustment
|
Remove
LE
to
(Record
input
signals
TP103,
TP203
Amp.)
Adjustment | mput Jacks al on Main P.C.B.
=
on Main P.C.B.
Same as above
Main P.C.B.
L103,L203
Adjust
L103
(L203)
to
obtain
maximum
read-
ing
on
the
VTVM.

Record
Level
Calibration
and
Recording
Bias Current
Adjustment
SIGNAL
SOURCE
OUTPUT
CONNECTION
400 Hz (0 dB),
400 Hz
(—20 GB),
10 kHz
(—20 dB) and
17 kHz
(—20 dB)
to Input Jacks
VTVM to
TP101, TP201
and
TP102, TP202
on Main P.C.B.
and
VTVM and
Distortion Meter
to Output Jacks
ADJUST-
MENT
REMARKS
Main P.C.B.
(Level)
ZX:
Record and Playback Mee 102,VR202
Tape SW — ZX/SX/EX .
Eq. SW — 70 us VE LOd RAS
(ZX/SX) -
120 us (EX) VR104,VR204
Dolby NR SW —
C-Type/B-Type/
OFF
(Bias)
ZX:
VR105,VR205
SX:
MPX SW — OFF
VR106,VR206
EX:
VR107,VR207
Adjustment should be made in the order of ZX,
SX and EX.
1
2
3.
4, Feed in 400 Hz, then adjust the Input Level
. Set the Doiby NR switch to C-Type.
. Connect a VTVM to TP101 (TP201) on the
Main P.C.B. Ass’y.
Set the BX-2 in Record/Pause mode.
control to obtain 350 mV (0 dB) on the
VTVM.
. Load a reference ZX tape (DA090374A),
reference SX tape (DA09025A) and refer-
ence EXII tape (DAO9066A).
. Adjust Record Cal. VR102 (VR202) for
ZX, VR103 (VR203) for SX and VR104
(VR204) for EXIT to center positions,
. Connect the VTVM to TP102 (TP202) on
the Main P.C.B. Ass’y. Adjust Bias VR105
(VR205) for ZX, VR106 (VR206) for SX
and VR107 (VR207) for EXII to obtain the
following bias current in Record/Pause
mode (the VTVM is connected across a 10-
ohm resistor).
ZX: approx.1mA
SX: approx. 0.5 mA
EX: approx. 0.3 mA
. Connect the VTVM to the Output Jacks,
. Feed in 400 Hz (—20 dB) and 17 kHz (—20
Saaiel then record, rewind and play them
back,
Adjust Bias VR105 (VR205) for ZX,
VR106 (VR206) for SX and VR107
(VR207) for EXII to obtain the same play-
back levels at 400 Hz (—20 dB) and 17 kHz
(—20 dB) on the VTVM.
. Feed in 400 Hz (0 dB), then record, rewind
and play it back,
Adjust Record Cal. VR102 (VR202) for
ZX, VR103 (VR203) for SX and VR104
(VR204) for EXII to obtain 0 dB on the
VTVM.
Repeat above 9 and 10 two or three times
to obtain optimum performance,
. Set the Dolby NR switch to OFF.
. Feed in 400 Hz (—20 dB), 10 kHz (—20 dB)
and 17 kHz (—20 dB), then record, rewind
and play them back.
Check to insure that the playback levels are
within —20 dB +3 dB against the levels in
Dolby NR C-Type.
Set the Dolby NR switch to B-Type,
. Feed in 10 kHz (—20 dB) and 17 kHz (—20
dB), then record, rewind and play them
back.
Check to insure that the levels are within
—20 dB +2 dB against the levels in Dolby
NR OFF.
. Check to insure whether the total harmonic
distortion is less than 1.0% for ZX and EXII
tapes and 1.2% for SX tape.
. If above is not sufficient, repeat 9 to 16 till
satisfactory results are obtained.
Overall
Frequency
Response
Adjustment
400 Hz (0 dB)
and 20 Hz to
17 kHz
(—20 dB) to
Input Jacks
1 kHz to
Input Jacks
VTVM to
Output Jacks ©
1 kHz Band Pass
Filter and VTVM
to Output Jacks
Record and Playback
Tape SW — ZX/SX/EX
Eq. SW — 70 us
(ZX/SX)
120 us (EX)
Dolby NR SW — OFF
MPX SW — OFF
Main P.C.B.
L102,L202
Record and Playback
Tape SW — ZX
Eq. SW —70us
Dolby NR SW — OFF
MPX SW — OFF
. Set the BX-2 in Record/Pause mode,
. Feed in 400 Hz, then set the Input Level
control to obtain 0 dB (500 mV) on the
VTVM.
3. Decrease the generator output control by 20
dB
. Feed in 20 Hz to 17 kHz (—20 dB) and
. If above
record, rewind and play them back, then
check to insure whether the output levels
are within —20 dB +4 dB.
is not sufficient, adjust L102
(L202) to obtain approx. —20 dB on the
VTVM, then conduct step 10 “‘Record Level
Calibration and Recording Bias Current
Adjustment”’,
. If above is not sufficient, precise re-adjust-
ment of step 6 ‘‘Playback Frequency Re-
sponse’’, replacement of Record/Playback
Head or check on item 2.6 “Tape Travelling
Check” will be required,
. Erase the tape with bulk eraser,
. Adjust the Input Level control to obtain
0 dB on the VTVM, and record the signals
on the reference ZX tape (DA09037A).
3. Turn the cassette tape the other way round
and play it back.
. Measure the difference between 2 and 3,

SIGNAL
SOURCE
OUTPUT
CONNECTION
MODE
REMARKS
Channel
Separation
Measure-
ment
1kHz to
Input Jacks
1 kHz Band Pass
Filter and VTVM
to Output Jacks
Record and Playback
Tape SW — ZX
Eq. SW — 70 us
Dolby NR SW — OFF
MPX SW — OFF
. Erase the tape with bulk eraser.
. Adjust the Input Level control to obtain
0 dB on the VTVM, and set the Balance
control to the extreme left (right).
. Record, rewind and play it back, then mea-
sure the R ch (L ch) level.
100 Hz to
Input Jacks
100 Hz Band
Pass Filter and
VTVM to
Output Jacks
Same as above
. Erase the tape with bulk eraser.
. Adjust the Input Level contro! to obtain
0 dB on the VTVM, and record the signals
on the reference ZX tape (DA09037A),
3. Rewind the tape, set the Input Level control
to minimum, and then record again.
. Rewind the tape, play it back, and then
measure the difference between 2 and 3.
Signal to
Noise Ratio
Measure-
ment
400 Hz to
Input Jacks
IHF-A Curve,
Filter, VTVM
and Distortion
Meter to
Output Jacks
Record and Playback
Tape SW — ZX
Eq. SW — 70 us
Dolby NR SW —
B-Type/C-Type
MPX SW — OFF
. Set the Dolby NR switch to B-Type/C-Type.
.
Feed
in
400
Hz,
then
record,
rewind
and
play
it
back,
.
Adjust
the
Input
Level
control
to
obtain
3%
total
harmonic
distortion
in
Playback mode.
. Set the Input Level control to minimum
then record again.
.
After
rewound,
play
back
and
check
the
2
3
4
5
L
output level difference between 3 and 4.
Note: The filter of IHF-A curve shall be used in
the measurements.
Total
Harmonic
Distortion
Measure-
ment
VTVM and
Distortion Meter
to Output Jacks
400 Hz to
Input Jacks
Record and Playback
Tape SW — ZX/SX/EX
Eq. SW — 70 us
Dolby NR SW — OFF
MPX SW — OFF
.
Adjust
the
Input
Level
contro]
to
obtain
0
dB
on
the
VTVM.
.
Record,
rewind
and
play
it
back,
.
Read
the
distortion
meter
and
check
to
insure
that
the
distortion
is
as
follows:
1.0%
or
less
1.2%
or
less
1.0%
or
less
4.2
3 kHz Speed
and Wow/
Flutter Tape
(DA09006B)
Wow/Flutter
Meter to
Output Jacks
Playback
. Dolby NR Circuit Check
Dolby
NR
circuit
incorporates
Dolby
NR
ICs
which
have
no
adjustment
point.
Perform
the
following
checks
and
make
sure
that
the
IC
operates
accurately,
ie.,
frequency
response
through
IC
is
accurate,
4.2
qd)
(a)
(b)
(c)
(2)
(a)
(b)
(ce)
(a)
.1. Dolby NR B-Type Circuit Check
Playback Dolby NR Circuit
Signal
Source:
1.4
kHz
to
negative
side
of
C134
(C234)
on
Main
P.C.B,
(Positive
side
is
connected
to
IC101-9
(IC201-9)).
VTVM
to
test
point
TP101
(TP201)
on
Main
P.C.B.
Stop
Dolby
NR
SW
—
ON
(B-Type)/OFF
Connect
a VITVM
to
TP101
(TP201)
on
the
Main
P.C.B.
Ass’y,
Set
the
Dolby
NR
switch
to
B-Type.
Feed
in
1.4
kHz
and
adjust
the
generator
output
control
to
obtain
35
mV
on
the
VTVM.
Set
the
Dolby
NR
switch
to
OFF.
Check
to
insure
that
the
reading
is
+3.2
dB
+1.5
dB
on
the
VTVM.
Output Connection:
Mode:
Record Dolby NR Circuit
Signal Source: 1,4 kHz to Input Jacks
Output
Connection:
VTVM
to
test
point
TP101
(TP201)
and
negative
side
of
C140
(C240)
on
the
Main
P.C.B.
Record/Pause
Dolby
NR
SW
—
ON
(B-Type)/OFF
Connect
a
VTVM
to
TP101
(TP201)
on
the
Main
P.C.B.
Ass’y,
Feed
in
1.4
kHz
and
adjust
the
Input
level
control
to
obtain
35
mV/11.1
mV
on
the
VTVM.
Remove
the
VITVM
from
TP101
(TP201)
and
reconnect
it
to
negative
side
of
C140
(C240).
Check
to
insure
that
the
reading
at
C140
(C240)
corresponds
to
the
following
with
Dolby
NR
switch
OFF
and
B-Type.
Mode:
Input
Level
Level
at
negative
side
of
C140
(C240)
at
TP101
(TP201)
|
Dolby
NR
OFF
Dolby
NR
B-Type
35
mV
0 dB +3.2 dB +1.5 dB
111
mV
0
dB
+8.2
dB
+1.5
dB
Eq. SW — 70 us
Play back and read the wow/flutter meter.
4.2.2, Dolby NR C-Type Circuit Check
q)
(a)
(b)
(c)
(2)
(a)
(b)
(ec)
(d)
Playback Dolby NR Circuit
Signal Source: 1.4 kHz to negative side of C134
(C234) on Main P.C.B. (Positive side
is connected to 1C101-9 (IC201-9)).
VTVM to test point TP101 (TP201)
on Main P.C.B.
Stop
Dolby NR SW — ON (C-Type)/OFT
Connect a VTVM to TP101 (TP201) on the Main P.C.B.
Ass’y.
Set the Dolby NR switch to C-Type.
Feed in 1.4 kHz and adjust the generator output control to
obtain 35 mV on the VTVM.
Set the Dolby NR switch to OFF,
Check to insure that the reading is +6.5 dB +1.5 dB on the
VTVM.
Output Connection:
Mode:
Record Dolby NR Circuit
Signal Source: 1.4 kHz to Input Jacks
Output Connection: VTVM to test point TP101 (TP2)3)
and negative side of C140 (C240)on
the Main P.C.B.
Record/Pause
Dolby NR SW — ON (C-Type)/OFF
Connect a VTVM to TP101 (TP201) on the Main P.C,B.
Ass’y.
Feed in 1.4 kHz and adjust the Input level control to obiain
35 mV/11.1 mV on the VTVM.
Remove the VTVM from TP101 (TP201) and reconnect ii to
negative side of C140 (C240).
Check to insure that the reading at C140 (C240) correspm ds
to the following with Dolby NR switch OFF and C-Type.
Mode:
Input Level Level at negative side of C140 (C240)
at TP101 (TP201) | Dolby NR OFF | Dolby NR C-Type)
35 mV 0 dB +6.5 dB +1.5 dB
11.1 mV
0 dB +11,4 dB +1.5 dB

MECHANISM ASS’Y AND PARTS LIST
5.
5.1, Synthesis
Fig. 5.1

Description ow
Synthesis (UK)
Synthesis (U.S.A. & Canada)
Synthesis (Japan)
Synthesis (Others)
Synthesis (Australia)
Synthesis (220V Class 2)
Serial No.: A31701001 - (Black)
Le eee. eee ee
Synthesis
(UK)
HA04348A
Synthesis
(U.S.A.
&
Canada)
HA04349A
Synthesis
(Japan)
HA04350A
Synthesis
(Others)
HA04351A
Synthesis
(Australia)
HA04352A
Synthesis
(220V
Class
2)
HA04353A
Serial
No.:
A31601001
-
(Silver)
Schematic
HA04342A
HA04343A
HA04344A
HA04345A
HA04346A
HA04347A
HA04362A
|
Cassette
Case
Cover
Ass’y
HA04363A
|
Cassette
Case
Cover
Ass’y
0H04133B
|}
Front
Panel
0H04134B
|
Front
Panel
0H04107A
|
Slide
Switch
Knob
0H04108A
|
Slide
Switch
Knob
0H04155B
0HO4156B
|
Top
Cover
Top Cover
Synthesis Mechanism Ass’y (UK)
Synthesis Mechanism Ass’y
(U.S.A. & Canada)
Synthesis Mechanism Ass’y
JA03963B | Synthesis Mechanism Ass’y (UK)
JA03964B | Synthesis Mechanism Ass’y
(U.S.A. & Canada)
JA03965B | Synthesis Mechanism Ass’y
JA03957B
JA03958B
JA03959B
(Japan)
(Japan)
JAO3960B
|
Synthesis
Mechanism
Ass’y
JA03966B
|
Synthesis
Mechanism
Ass’y
(Others)
(Others)
JA03961B
|
Synthesis
Mechanism
Ass’y
JA03967B
|
Synthesis
Mechanism
Ass’y
(Australia)
(Australia)
JA03968B | Synthesis Mechanism Ass’y
JA03962B
(220V Class 2)
Synthesis Mechanism Ass’y
(220V Class 2)
0J04605B
|
Bottom
Cover
0J04605B
|
Bottom
Cover
0J03564A
|
Leg
T-H
0J03564A
|
Leg
T-H
0M04377A
|
Caution
Label
0M04377A
|
Caution
Label
0M03551B
|
Pass
Label
B
0M03551B
|
Pass
Label
B
0J04630A
|
Rubber
0J04630A
|
Rubber
0J04629A
0J04628A
0E03054A
0E03032A
Top Cover Cushion B
Top Cover Cushion A
BT 3x8 ®Countersunk
BT 4x8 © Pan Washer Faced
(Black Chromate)
BT 3x6 © Binding
BT 3x10 © Binding
Voltage Label 220V
(220V Class 2)
Voltage Label 240V
(UK & Australia)
Cord Label (UK)
0J04629A
0J04628A
0E03054A
0E03033A
OEO0857A
OE00865A
OM03796A
0M03797A
Top Cover Cushion B
Top Cover Cushion A
BT 3x8 © Countersunk
BT 4x8 ® Pan Washer Faced
(Nickel)
BT 3x6 9 Binding
BT 3x10 © Binding
Voltage Label 220V
(220V Class 2)
Voltage Label 240V
(UK & Australia)
Cord Label (UK)
OEO0857A
OEOO865A
OM03796A
OM03797A
0M03844B
0M03844B
Bee ee eS HOO PRN NEPREPN RE BP BP HF Be eee bee
Bee eEeE FP HOOD BPN NE PNP HB BE Be oF BRE
0M04397A
|
Serial
Number
Plate
0M04397A
|
Serial
Number
Plate
0M04113A
|
LA
Label
(U.S.A,
&
Canada)
0M04113A
|
LA
Label
(U.S.A.
&
Canada)
0M04293A
|
Voltage
Seal
(Others)
0M04293A
|
Voltage
Seal
(Others)
0M04185A
|
FSZ
Mark
Label
(220V
Class
2)
0M04185A
|
FSZ
Mark
Label
(220V
Class
2)

5.2. Synthesis Mechanism Ass’y (A01)
U.S.A.,Canada,Japan & Others
53
55
UK, Australia & 220VClass2
JA03957B
JA03958B
Synthesis Mechanism Ass’y (UK)
Synthesis Mechanism Ass’y
(U.S.A. & Canada)
Synthesis Mechanism Ass’y
BA04804A
BA04802A
‘BA04905A
JA03959B
(Japan) BAO04800A
JA038960B | Synthesis Mechanism Ass’y
(Others) 0B06378A
JA03961B | Synthesis Mechanism Ass’y BAO4801A
(Australia) BA04803A
JA03962B | Synthesis Mechanism Ass*y
(220V Class 2)
Serial No.: A31601001 - (Silver)
0H08511A
0J04611A
CA08399A
HA04390A
0J04604B
0J04076A
BA04823A
0H04137A
0H04129A
0J04607A
0H04125A
0J04608A
0H04112A
0H04110B
0H04139B
0H04143A
0H04141B
0HO4116A
0H04118A
0H04120A
0H04123B
0H04121C
0J04610A
0J04606A
0H04105A
0H04103B
0H04113A
OHO4157A
0H04618A
BA04805A
Front Chassis
Eject Button
Eject Spring
Power Switch Button
Power Switch Spring
Meter Cover
Meter Scale
Reset Button
Control Button A
Record Mute Button
Control Button B
Control Button C
Lens
Dolby NR Switch Button
Eq. Button
Ea. Switch Spring
Button Joint
Master Volume Knob
Balance Volume Knob
Volume Plate
Volkume Cover
Volume Shield Plate
Volume P.C.B. Ass’y
BA04824A
BA04825A
0J04603D
BA04906A
BA04861A
OJ04581A
0H04102A
0J304602D
BAO04806A
0C01162B
OBO6699A
OB06698A
OBO6697B
0B06700B
0H04152B
Pa fk ek bak fe NE a Bat 19 OU Bet eek eh fake tah fe et ft ek bd
Dolby NR Switch P.C.B. Ass’y
Control Switch P.C.B. Ass’y
Counter P.C.B. Ass’y
(2nd Version)
Counter P.C.B. Ass’y
(1st Version)
Display P.C.B.
Indicator P.C.B. Ass’y
Timer Switch P.C.B. Ass’y
Headphone Jack
Headphone Plate
Mechanism Ass’y
Cover Plate Ass’y
Power Switch Joint
Power Switch Holder
Power Switch P.C.B. Ass’y
(U.S.A, & Canada)
Power Switch P.C.B. Ass’y
(UK, Australia, Others &
220V Class 2)
Power Switch P.C.B. Ass’y (Japan)
Side Chassis L
Main P.C.B. Ass’y (2nd Version)
Main P.C.B. Ass’y (1st Version)
Main P.C.B. Cushion
Function Switch Knob
Side Chassis R
Pin Jack P.C.B. Ass’y
Bolt Receptacle Plate
Power Transformer (UK,
Australia & 220V Class 2)
Power Transformer
(U.S.A. & Canada)
Power Transformer (Japan)
Power Transformer (Others)
Rear Panel
BOER eR Re Re
BER fe BNR PRN REE
|
|
4
;
8