Nakamichi High-Com II User manual

Nakamichi
Service Manual
Nakamichi
High-Com II
Noise Reduction System

CONTENTS
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1. GENERAL
1.1. Control Functions
The Nakamichi High-Com II control functions are shown below:
Tr Wasiaraknd sigtt~Coni 1 poles Reduction Syareon
Fig. 1.1 Front View
Fig. 1.2 Rear View
1.2, Voltage Selactor
1.
Peak-Level
Meters
9.
2.
Mode
Switch
40.
3.
Filter
Switch
+1.
4,
Output
Contro!
12,
5.
Inout
Level
Control
13,
6.
Master
Input
Level
Control
14.
7.
GND
Jack
15.
8.
Line
Jacks
7
Line In Jacks
Rec, Out Cal, Controls
Rec. Out Jacks
Play In Jacks
Play In Cal. Controts
Line Out Jacks
Power Cord
Voltage selector is installed on the rear panel for other versions of the Nakamichi High- -Com Il.
This voltage selector can select either 120 V or 220-240 V at customer's disposal.

2. PRINCIPLE OF OPERATION
2.1. High-Com Hi Noise Reduction System
The Nakamichi High-Com Ij is a-noise reduction system
furnished with peak level meters, a 19 kHz MPX filter, a
10 Hz subsonic filter and a built-in 400 Hz tone oscillator.
Following are the outline of the High-Com II:
{a)_ Compression (encoding) is made at recording and
expansion (decoding) at playing back. The ratio of
input to output is 2:1 in compressor, vice versa in
expander.
{b} Frequency is divided into two bands of area for the
reduction of noise and the noise reduction as a whole
is about 20 to 25 dB.
(c)
priate attack-time or release time.
Further, special measures are taken.to keep: off iesits
ing disturbance.
Fig. 2.1 shows the block diagram of the High-Com lt.
Operation of the High-Com this done by. the Mode Switch
and the Filter Switch.
Line input signal is fed through independently separated
input level control for L or R channel and simultaneously
variable master control for L and R channels and reaches
L.P.F.
With this L.P.F.,higher frequency over 22 kHz, i.e., the -
frequency over audible frequency is eliminated.
Next to L.P.F. are a MPX filter and a subsonic filter which
permit the selection of 4 different stages of Subsonic, Off,
MPX, or MPX/Subsonic with the use of Filter Switch.
At the further stage, it has a compressor or expander com-
posed of U401B ICs and peripheral circuits, that permit’
* [aoa Hz
Osc.
Input
Level Master
Coloration of sound is eliminated by means of saad :
the selection of Cat. 400 Hz, Rec. (Encode), Pass, or Play
{Decode) with the use of Mode Switch. ;
At recording, select Rec. with the Mode Switch.
Compressed line input signal will appear at Rec. Out
Jacks, while the original signal wilt appear at peak level
meters and at Line Out Jacks.
For playback, select Play with the Mode Switch. Then,
the expanded play input signal will appear on both Line
Out Jacks and peak level meters.
Preceding input signal will reach L.P.F. and H.P.F. via
amp, Frequency is divided into two bands, higher band
and tower band, by H.P.F. and L.P.F. respectively, and
these two bands are either compressed or expencen by the
compressor or the expander,
Compression or expansion is performed by the changes of
amplifying rate of amplifier through the VCR (Voltage
_ Controt Resistor). The VCR is varied by the level sensor
output in correspondence with the input signal level and
the frequency.
Following shows the block diagram of the iC U401B.
U401B __ 18, 18 20 22 24
Output
ia
Filter Switch:
Mode Switch:
A. Cae. 400H2
con
+ .
1,
Subsonic
:
H
2. Ott
3. MPX
A. Subsonic / PX
8. Record Ag : io
C. Poss Bo - Rec.
OC, Playbock c Output
Fig. 2.1 High-Com I! Biock Diagram

(1) Compressor (Encoding)
Fig, 2.2 is the basic circuit of the compressor.
V1 sand V2 are variable gain amplifiers, and they are so
designed that each of them keeps the same gains, The
gains of V1 and V2 are so made that P2 is always kept
at a constant level by the control of the feedback signal
sent through the level sensor.
This function is shown in Fig. 2.3.
The gain of Vi and V2, SP1 and AP2, remains always the
same, therefore as seen in the figure, output Pt, the thick
Jine, comes out to be 1/2 of the gradient of PO.
For instance, ~40 dB input at input PO will be com-
pressed to —20 dB at output P1.
This compression principle is very simple. if V1 and V2
are equat, then the output P1 will always be 1/2 of the
input PO.
Fig. 2.2
input (dB)
“40 -30 -20 “19
Pa are
wo o
Output (dB)
-40
Po:
Fig, 2.3
(2} Expander (Decoding)
Fig. 2.4 is the basic circuit of the expander.
_ Compressed signal is fed to V1‘ and V2’ from P1’.
V2' is similar to V1 and V2 amplifiers of the compressor.
Level sensar and V2’ operate so as to keep output signal
level P2’ at a constant level.
Level sensor output is given to V1‘ as well. Gain of V1‘ is
1/V and therefore the compressed input P1’ will be ex-
panded by V1’, and subsequently the original signal is
obtained at output PO’.
‘This is shown in Fig. 2.5. Output PO’, the thick line, is
two times the gradient of Pt’. For instance, —-20 dB input
at input PT’ is expanded to —40 dB at output PO’.
PY Po
1“¥
ve
y > PZ
Le eee
: Level
Sensor
Fig. 2.4
Input (dB)
-40 -30 -20 -10
j re)
Output (dB)
Pr’ Po’
Fig, 2.5
The basic circuit of V1 and V2 of Fig. 2.2 and V2’ of Fig.
2.4 is shown in Fig. 2.6.1. On the other hand, the basic
circuit of V1' is connected as shown in Fig. 2.6.2 in order
to obtain the reciprocal of V2’ gain,
Zt
Vq=~—~—— V3
21+ Ze
Fig. 2.6.2
ities aR TE , Soh dele ak
pre ee
er
oe eee

Input signal is divided into two bands, each of which is expansion, with the parameter for example 50 Hz, 400 Hz,
independently separated in performing compression or 3 kHz and 10 kHz. '
expansion, and subsequently the modification in noise at :
the lower band, so called breathing noise, is intercepted. vi],
This division of two bands results in noise reduction ;
approximately by 20 dB in both bands, not only in the si Pee ae
higher band but also in the lower. band as well.
Further, in each of these two bands of frequency, differ-
ent time constants are used for controlling the amplifying
rate so as to reduce the distortion of the middle and lower
band and to improve the response at the higher band, pre-
venting the tone quality from deterioration.
Fig. 2.7 indicates the compression characteristics. From
this chart you can see the changes of compression fevel in
accordance with the frequency, for instance, less compres-
sion to lower frequency and more compression to higher
frequency. But you will see the limit at the higher fre-
quency band that no compression is made below —40 dB.
As the frequency goes up to a higher value, the operating
point of compression shifts to the lower level and lowers
the recording level at the higher frequency. This is to put
i
Output Level(dB)}
the saturation level into consideration at the higher band Sy See ee, ee Se ee on eG aN ey
Input Level(dB)
on the tape deck,
From the chart of the Fig. 2.8, you can read the input Fig. 2.8 Compression (Encode) and Expansion
level. vs output level characteristics of compression and (Decode) Characteristics
Rec, Out Level (dB)
20 50 © 100 200 500 1K 2k OK 10K 20K
Frequency (Hz)
Fig, 2.7 Compression {Encode} Characteristics

2.2. Subsonic Filter -
The frequency response of ordinary hi-fi phono cartridges
covers the subsonic range. The resonance point is near 10
Hz with a peak of 5 to 15 dB. These factors are
determined by the mass, compliances and damping resist-
ance of the cartrige and tone arm. Further, near the —
resonance frequency, the disc record is likely to be
eccentric or warped, or the turntable vibrates abnormally.
In extreme cases, the resonance frequency increases to the
level of disc record playback signals (the worst condition
occurs when the vibration caused by the speaker is fed
back to the cartridge via air or floor vibration). Usually,
the subsonic effect thus produced is not found. Because |
of inter-modulation distortion, the subsonic effect causes
unclean sound from amplifier, speakers or tape decks, It
especially affects such systems whose response curves
cover lower frequencies {note that, if the woofer moves
unsteadily during playback of disc records, the above-
mentioned adverse effect can be produced}.
The turntable, cartridge and tone arm must be improved
to completely eliminate subsonics. However, even im-
proved turntable, etc. could not completely eliminate
subsonics. One solution of this problem so far achieved is
using commercially available preamplifiers that incorpora-
te subsonic fitters. But most of them shows poor
attenuation curves of 6 dB/Oct. or 12 dB/Oct., and they
can not sufficiently eliminate subsonics. And they have -
fault to attenuate the low frequency band {near 30 to 40
Hz}. The subsonic filter used in the High-Com II, based on
the new active filteration technology, can realize an ideal
filter characteristic,
Fig. 2.9 shows the subsonic filter of the High-Com II. The
portion represented by FT is generatly known as a twin T
filter, Its characteristics are illustrated in Fig. 2, 10 (1). As
shown, the curve of the twin T filter rapidly drops at 20
to 50 Hz, and attenuation at below 5 Hz is rather small.
These demerits have been smartly eliminated by the
High-Com II as foflows:
Input
C107
680OP{N }
Improvement 1: Improved Twin T Filter with Boot Strap’
As shown in Fig. 2.9, the output from the twin T filter is
amplified by OP-amp. |C302 and taken from its output
terminal. This output provides positive feedback to the
non-inverting input of 1C302 through C107 and R109.
‘This greatly reduces the level down in the range 20 to 50
Hz. For greater attenuation in the range below 5 Hz,
R110 is added to lower the load impedance of the filter
and to change the impedance of each element so that the
asymmetric curve as shown by Fig. 2.10 (2) can be
achieved, .
Improvement 2: Addition of CR Filter
The curve shown in Fig. 2.10 (2) is satisfactory for the
subsonic filter except insufficient attenuation at below 5
Hz,
Besides the High-Com 1I uses a CR filter consisting of
C108 and R112 to achieve a more ideal subsonic filter
curve as shown by Fig. 2.10 {4}. (In Fig. 2.10 (3) shows
the CR filter curve and {4) is a combination of curves (2)
and (3).}
“104
1
Ny oO
ri
-304
ATTENUATION (dB)
~404
-504
- : +
3 5 10 20 70 100
FREQUENCY iHz}
Fig. 2.10
Posbtaree aac Foe
ctrog
O.OSbut)
Output
Rit2
120K
a
Fig. 2.9 Subsonic Filter Circuit
pea

2,3. Mute Signal
Output signals are muted for a certain time to prevent
transient noise when power is ON or OFF, Fig, 2.11 shows
the mute circuit and Fig. 2.12 shows a timing chart of the
mute signals,
2.3.1. Power ON
Transformer output is rectified through diode D402 and
smoothed by capacitor C401. Therefore, positive poten- —
tiat appears at C401 (transistor O401 base}, That is, 0401
is in the cutoff state, while C402 (47 uF) is charged with
negative potential through R404 (2.2 MQ). At the level
where the voltage across C402 exceeds Vbe {base-emitter ©
voltage} of 402, O402 turns from OFF to ON, As a
result, Q403 turns ON and the mute signal is changed
from + V to —12 V, releasing the mute state. This means
the mute time depends on C402 and R404 after power is
ON,
2.3.2, Power OFF
Transformer output becomes zero, as a result of which
C401 is charged with negative potential through R403. At
the level where the voltage across C401 exceeds Vbe of
0401, 0401 turns from OFF to ON and C402 is quickly
discharged. Thus, 0402 is cut off and Q403 is also cut off.
+V¥
D403
i : C403
Output
Mute )4-7K
0403
280945
2
2208 25V 47 1OVILN)
The mute signal voltage becomes positive to mute the
output signal. D403 acts to prevent + V from being
discharged easily when power is OFF..
Power ON
Switch :
OFF
c4o1 pas Oe \ t
. Q401 Vbe\,
Q402 Vbe 1
C402 we 1 =
0402 me =
Coliecfor
-12V
+V
Mute
OV
-12V
Open SS ———S
Output ' !
ov——— Los
Fig. 2.12 Timing Chart
0402
R40)
270K
Fig. 2.11 Mute Circuit

3.5. Main P.C.B. Ass’y
Refer to Fig, 3.2.
(1) Refer-to Fig, 3.1. Remove Front Pane! Ass’y referring
to item 3.4.
{2) Remove the connector and wires connected by wrap-
ping from FQ2 (Main P.C.B. Ass’y}.
(3) Remove FO1, then disassemble FO2 (Main P.C.B.
Ass‘y). ,
3.6. Power Transformer
Refer to Fig. 3.2,
(1) Refer to Fig. 3.1, Remove Top Cover Ass‘y referring
to item 3.1.
(2) Remove F03 and F04, then disassemble FOS (Power
Transformer). ,
3.7. Meter Ass’y, Meter and Lamp P.C.B. Ass‘y
Refer to Fig. 3.2.
(1) Refer to Fig. 3.1. Remove Front Panel Ass’y referring
to item 3.4. ;
{2} Remove FQ6, then disassemb!e FO7 (Meter Ass’y}.
(3) Remove FO8 (Meter Band), then disassemble FO9
{Meter).
Remove F10, then disassemble F114 (Lamp P.C.B.
Ass’y).
—
(4
3.8. Power Switch
Refer to Fig. 3.2.
{1} Refer to Fig. 3.1. Remove Front Panel Ass’y referring
to item 3.4,
{2) Remove F12, F13 (Power Switch Flange} and Fi4,
then disassemble F15 (Power Switch),
3.9. Rear Panet Ass’y
Refer to Fig. 3.3.
{1) Refer to Fig. 3.1. Remove Top Cover Ass‘y and
Bottom Cover Ass’y referring to items 3.1 and 3.2,
{2) Remove FO1, then disassemble FO2 (Rear Panel
Ass'y).
3.10. 2P Pin Jack and Voluma
Refer to Fig. 3.3.
(1} Refer to Fig. 3.1. Remove Top Cover Ass‘y and
Bottom Cover Ass’y referring ta items 3,1 and 3,2.
(2) Pull out FO3 (Volume Knob), Remove F04 and FO5,
then disassemble FO6 (Volume 10 KQ{B)) and FO7
(Volume 50 KQ(B)).
(3) Remove FO8, then disassemble FOS (2P Pin Jack}.
FO2

3. REMOVAL PROCEDURES
3.1. Top Cover Ass'y
Refer to Fig. 3.1. Remove F01 and F02, then disassemble
FO3 (Top Cover Ass’y).
3.2, Bottom Cover Ass’y
Refer to Fig. 3.1. Remove F04, then disassemble FO5
(Bottom Cover Ass’y).
3.3. Side Panel Ass’y
Refer to Fig. 3.1, Remove FO6 and F07, then disassemble
FO8 (Side Panel Ass‘y).
3.4. Front Panel Ass’y and Meter Escutcheon
(1) Refer to Fig. 3.1, Remove Top Cover Ass’y, Bottom
Cover Ass’y and Side Panel Ass’y referring to items
3.1 through 3.3.
(2) Pull out FO9 {Volume Knob A Ass’y) and Ft0
(Volume Knob B Ass‘y}, Remove F11, then disassem-
ble F12 (Front Panel Ass’y}.
{3) Remove F13 (Meter Escutcheon).
FOS
FO4
Fig. 3.1

FO!
Fig. 3.3
4. ADJUSTMENTS AND MEASUREMENTS
Refer to Fig. 4.1 connecting diagram and Fig. 4.2 diagram for adjustment.
High-Com IL
input Impedance: 500Knor more
—
Line In
Rec. Out
t
|
sw
Play In
Oscilloscope
Line Out
10Hz OdB
400H2 0dB|400H2z O48
+10dB
-60d8
1OKHz +10dB|10KHz -6dB
-60d8
I9KHz dB
Fig. 4.1 Connecting Diagram i

VR205
Meter
Level
YR3O1
ia Tone Level
¢102 C103
Fig. 4.4 400 Hz Tone Level
Low Band Ref. Level
Q
vRI02 VR202
Eos: Low Band off-set ere
‘es Band Ret, Si
- ¥RIO3 VR203
oe
8 ial
= Hi Band off-set __
\ 202(@]
MPX
Fig. 4:2 Diagram for Adjustment
VRIOUYR201)
SOK ;
V¥R102 (VRZ202) 2M
20 22
iC 10
Fig. 4.5 High-Com II Low Band
¥RIO4(VR204) 2M
R146
20 22
IG1o2
Fig. 4.6 High-Com Il High Band
Fig. 4.7 Level Meter Amp. ©
11
toa Geeta on ven
ee

STEP ITEM SIGNAL SOURCE OUTPUT CONNECTION | move ADJUSTMENT REMARKS
MPX Filter Adjustment
400 Hz Tone Level
Adjustment
High-Com 11 Low Band
Adjustment
4 Hich-Com tt High Band
Adjustment
5 Encoding Characteristics
Measurement
Level Meter Amp.
Adjustment
Signal to Noise Ratio
Measurement
Subsonic Filter
Measurement
19 kHz +100 Hz (0 dB) to Line In VTVM to Line Out Jacks
Jacks
VTVM to Line Out Jacks
400 Hz (0 dB) to Play In Jacks VTVM to Line Out Jacks
10 kHz (-6 dB) to Play In Jacks VTVM to Line Out Jacks
400 Hz and 10 kHz (+10 dB, -60 dB) | VTVM to Line Out Jacks and
to Line In Jacks Rec. Out Jacks
400 Hz (0 dB) or 400 Hz Tone to
Line in Jacks VTVM to Line Out Jacks
VTVM to Rec. Out Jacks
10 Hz (0 dB) to Line In Jacks VTVM to Line Out Jacks
12
Mode SW — Rec.
Filter SW — OFF, MPX, and
MPX/Subsonic
Output Volume — Max.
Input Volume — Max.
Master Volume — Max.
Mode SW — Cal. 400 Hz
Output Volume — Max.
Input Volume — Max.
Master Volume — Max.
Mode SW — Play and Pass
Filter SW — OFF
Output Volume — Max.
Input Volume — Max.
Master Volume — Max.
Same as above
Mode SW — Rec. and Pass
Output Volume — Max.
Input Volume — Max.
Master Volume — Max.
Mode SW — Cal. 400 Hz and
Rec.
Output Volume — Max.
Input Volume — Max.
Master Volume — Max.
Mode SW — Pass
Output Volume — Max.
Input Volume — Min.
Master Volume — Min.
Mode SW — Rec.
Filter SW — OFF, Subsonic, and
MPX/Subsonic
Output Volume — Max.
Input Volume — Max.
Master Volume — Max.
L102, L202
VR101, VR201
VR102, VR202
VR103, VR203
VR104, VR204
VR105, VR205
4. Feed in 400 Hz +10 dB, then check to insure that the reading on the VTVM
. Set Filter Switch to OFF, then adjust the external oscillator output level
to obtain 600 mV on the VTVM for both channels.
. Set Filter Switch to MPX, then adjust coil L102 (L202) to obtain a
minimum reading on the VTVM.
The minimum reading should be —30 dB or Jess.
. Set Filter Switch to MPX/Subsonic, then check to insure that the reading
on the VTVM is —30 dB or less for both channels.
Adjust VR301 to obtain 600 mV on the VTVM.
. Set Mode Switch to Pass, then adjust the external oscillator output level to
obtain 600 mV on the VTVM for both channels,
. Offset Adjustment of IC U401B:
Set Mode Switch to Play, then adjust VR102 (VR202) to obtain a minimum
reading on the VTVM.
. Low Band Reference Level Adjustment:
Set Mode Switch to Play, then adjust VR101 (VR201) to obtain 600 mV on
the VTVM.
1. Set Mode Switch to Pass, then adjust the external oscillator output level to
obtain 300 mV on the VTVM for both channels.
2. Set Mode Switch to Play, then adjust VR104 (VR204) to obtain a minimum
reading on the VTVM.
3. Set Mode Switch to Play, then adjust VR103 (VR203) to obtain 300 mV on
the VTVM.
. Connect VTVM to the Line Out Jacks.
Set Mode Switch to Rec., then feed in 400 Hz and adjust the external
oscillator output level to obtain G00 mV on the VTVM for both channels.
2. Connect VTVM to the Rec. Out Jacks.
Set Mode Switch to Pass, then note signal levels obtained at the Rec. Out
Jacks. These signal levels are referred to as reference levels.
3. Set Mode Switch to Rec. and Rec. Out Cal. Controls on the rear panel at
the max, positions (fully CCW),
at the Rec. Out Jack is +5 +0.5 dB against the reference level for both
channels,
5. Feed in 400 Hz —60 GB, then check to insure that the reading on the VTVM
at the Rec. Out Jack is —-43.0 +2 dB against the reference level for both
channels.
6. Repeat above substeps 1 — 3 at 10 kHz instead of 400 Hz.
7. Feed in 10 kHz +10 dB, then check to insure that the reading on the VTVM
at the Rec. Out Jack is +2.2 +0.5 dB against the reference level for both
channels.
8, Feed in 10 kHz —60 dB, then check to insure that the reading on the VTVM
at the Rec. Out Jack is —38.5 +2 dB against the reference level for both
channels,
. Set Mode Switch to Cal, 400 Hz, then adjust VR105 (VR205) to obtain O
dB on the level meter.
2. Set Mode Switch to Rec., then feed in 400 Hz —20 dB and adjust R163
(R263) and R164 (R264) to obtain —20 +2 dB on the level meter.
. Repeat above substeps 1 and 2 to obtain the optimum performance.
1, Set Input Level Control and Master Input Level Control at minimum
positions.
2. Check to insure that the reading on the VTVM is —88 dB or less for both
channels,
Note: The filter of IHF A curve shall be used in the measurements.
. Set Filter Switch to OFF, then adjust the external oscillator output level to
obtain 600 mV on the VTVM for both channels,
2. Set Filter Switch to Subsonic, then check to insure that the reading on the
VTVM is —30 dB or less for both channels.
3. Set Filter Switch to MPX/Subsonic, then check to insure that the reading
on the VTVM is —30 dB or less for both channels.

5.
MOUNTING
DIAGRAMS
Note: Mounting diagram shows a dip side view of the printed circuit board.
5.1. Main P.C.B. Ass’y 5.2. Lamp P.C.B. Ass’y
CUS 10p 1Ov
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Fig. 5.1 Note: Diode is 1SS53 unless otherwise specified.
13

Schematic
Ref. No.
—
1C101, 102
201, 202
1C103, 104
105, 203
204, 205
1C106, 206
D101, 102
201, 202
VR101,201
VR102,104
202,204
VR103,203
R117, 156
217, 256
R118, 119
141, 170
218, 219
241, 270
R120, 123
220, 223
R121, 221
R122, 136
222, 236
R124, 135
224, 235
R125, 225
R126, 128
154, 226
228, 254
R127, 134
227, 234
R129, 140
150, 151
152, 229
240, 250
251, 252
R130, 142
230, 242
R131, 143
147,171
231, 243
247, 271
R132, 232
R133, 233
R137, 237
R138, 238
R139, 148
239, 248
R145, 245
R146, 246
R149, 249
R153, 253
BA04137A
BA04138A
BA04139A
BA04140A
BA04141A
— High-C
0B06242A
OB06146A
0B06124B
0B06181A
0B07237A
0B07306A
0B03831A
OB01889A
0B01888A
0B09230A
0B09203A
OBO9356A
OBO5698A
OB01857A
OBO5509A
OBOS560A
OBO5S641A
0B01887A
OBOS776A
OBO9359A
OBO5680A
OB09357A
0B01679A
OBOS508A
OBO5692A
OBO5625A
0B01683A
OBO1846A
Main P.C.B. Ass’'y (Japan)
Main P.C.B. Ass’'y (U.S.A. &
Canada)
Main P.C.B. Ass’y
(220V Class 2)
Main P.C.B. Ass’y (UK &
Australia)
Main P.C.B. Ass’‘y (Others)
om Il —
Ic U401B
IC RC4558DD
Ic RC4558D
Silicon Diode 18853
Semi-fixed Volume 50K (B)
Semi-fixed Volume 2M
Semi-fixed Volume 5K
Carbon Resistor 100K ERD-25T
Carbon Resistor 10K ERD-25T
Metal Film Resistor 1.5K SN14K2E
Metal Film Resistor 10K SN14K2E
Metal Film Resistor 4.7K SN14K2E
Carbon Resistor 1.5K ERD-25T
Carbon Resistor 1K ERD-25T
Carbon Resistor 33K ERD-25T
Carbon Resistor 18K ERD-25T
Carbon Resistor 47K ERD-25T
Carbon Resistor 5.6K ERD-25T
Carbon Resistor 1M ERD-25T
Metal Film Resistor 8.2M RK14B2E
Carbon Resistor 1.8M ERD-25T
Metal Film Resistor 33K SN14K2E
Carbon Resistor 100 ERD-25T
Carbon Resistor 56K ERD-25T
Carbon Resistor 68K ERD-25T
Carbon Resistor 220K ERD-25T
Carbon Resistor 15K ERD-25T
Carbon Resistor 4.7K .ERD-25T
R155, 255
R311, 312
C113, 130
213, 230
C114, 214
C115, 135
215, 235
C116, 216
C117, 217
C118, 119
139, 218
219, 239
C120, 121
220, 221
C122, 222
C123, 223
C124, 224
C125, 225
C126, 137
226, 237
C127, 136
140, 227
J} 236, 240
C128, 228
J} C129, 229
C131, 231
C132, 232
F] C133, 233
C134, 234
F] C138, 142
Fl 238, 242
C141, 241
J] C308, 309
Q101, 102
J} 201,202
ZD101,201
J | D103, 104
203, 204
VR105,205
R157, 257
R158, 258
J} R159, 259
R160, 260
J | R161, 261
R162, 262
R163, 165
263, 265
R164, 264
R166, 266
R310
weoqmew
C143, 243
C144, 244
C145, 245
C307
aa G&
14
Part No. Description sia Part No. Description
0B09263A } Carbon Resistor 12K ERD-25T J — Power Mute —
0B09210A | Fail Safe Type Resistor 33 RDF25S J
0B01389A | Electrolytic Capacitor 4.74 25V 1C401 OB06176A | IC uwA7T8M12
1C402 0B06177A | IC wA7T9M12
0B09370A | Ceramic Capacitor 33P 50V J] D401 O0B06183A | Diode Bridge RB151
0B01400A | Electrolytic Capacitor 100u 16V D402,403 | 0B06181A | Silicon Diode 18853
Q401,402 | 0B06013A | Transistor 2SA733
OBO5681A | Mylar Capacitor 0.01n 50V J} Q403 0BO06100A | Transistor 280945
O0B05653A | Mylar Capacitor 1500P 50V J| R401 OBO5620A | Carbon Resistor 270K ERD-25T J
0B01412A | Electrolytic Capacitor 10yu 16V R402 0B05776A | Carbon Resistor iM ERD-25T J
R403 0B09320A | Carbon Resistor 820K ERD-25T J
R404 0B05671A | Carbon Resistor 2.2M ERD-25T J
0B05557A | Mylar Capacitor 0.0152 50V J} R405 OBO5508A | Carbon Resistor 56K ERD-25T J
R406 OB01889A | Carbon Resistor 100K ERD-25T J
0809362A | Tantalum Capacitor 0.68 35V R407 0B01846A | Carbon Resistor 4.7K ERD-25T J
0B05584A | Mylar Capacitor 0.22u 50v J} C401 0B01780A | Mylar Capacitor 0.1 50v J
OBO5885A j Electrolytic Capacitor 100u 10V C402 0B09375A | Electrolytic Capacitor 47u 10V(LN
OBO9360A | Polyethylene Laminate Capacitor C403 0B01391A | Electrolytic Capacitor 220u 25V
0.68u 50V J | C404 OBO5654A | Electrolytic Capacitor 2200u 25V
OBO05582A | Mylar Capacitor 0.022u 50V J| C405 OB01870A | Electrolytic Capacitor 1000u 25V
C406, 407 |0B01502A | Electrolytic Capacitor 330n 16V
OBO5550A | Mylar Capacitor 1000P 50V J OBO8680B | Heat Sink A (2 pes.)
OE00507A | Nut Hex. M3 (2 pes.)
0E00612A | Screw M3x6 Philips Pan Head (2A)
0B05652A | Mylar Capacitor 4700P 50V J (2 pes.)
0B01802A | Mylar Capacitor 2200P 50V J OBO8515A | Insu-Lock (4 pcs.)
0B09222A | Electrolytic Capacitor 0.47u 50V
(LN) — Miscellaneous —
0B09235A | PP Capacitor 680P 100V J
0B01780A | Mylar Capacitor O.1u 50V J OB07858D | Main P.C.B.
0B05512A | Electrolytic Capacitor 2.2u 50V_ | 1€3071,302 | 0B06146A | IC RC4558DD
0B09151A | Electrolytic Capacitor 220u 6.3V 303
(LN) | 1304 0B06124B | IC RC4558D
0B09361A | Tantalum Capacitor 0.22 25V Q103,104 |OBO6070A | Transistor 28C1636
0B01398A | Electrolytic Capacitor 220u 16V 203, 204
OBO8699A | IC Socket 24P (4 pcs.) D105,205 | 0B06181A | Silicon Diode 1$S53
L101, 201 |0B03919B | Inductor 36mH
— Meter Amp. — L102,202 | 0B03563A | Inductor 23mH
VR108,208 | 0B07310A | Volume 100K (A)
OBOG062A | Transistor 2SC1222 VR30% 0B07261A | Semi-fixed Volume 20K
VR302 0B07231A | Volume 10K (A) x2
OBO6063A | Zener Diode YzZ040 VR303 0B07309A | Volume 100K (A) x2
OBO06181A | Silicon Diode 18S53 R101,113 | 0B01889A | Carbon Resistor 100K ERD-25T J
116,201
0B07237A | Semi-fixed Volume 50K 213,216
0B01682A | Carbon Resistor 68K ERD-25T J| 301,302
0B01889A | Carbon Resistor 100K ERD-25T J| 305,306
OB09358A | Metal Film Resistor GOK SN14K2E fF] R102,202 | OBO9369A | Carbon Resistor 62K ERD-25T J
0B01888A | Carbon Resistor 10K ERD-25T Jj R103,203 | OB01846A | Carbon Resistor 4.7K ERD-25T J
OBO9005A | Metal Film Resistor 24K SN14K2E Fj R104,204 | 0B05614A | Carbon Resistor 1.8K ERD-25T J
OB01856A | Carbon Resistor 8.2K ERD-25T J] R105,107 |0B05776A | Carbon Resistor 1M ERD-25T J
OB01680A | Carbon Resistor 820 ERD-25T J| 108,205
207, 208
OBOS5698A | Carbon Resistor 1.5K ERD-25T J|R106,206 |0B01887A | Carbon Resistor 5.6K ERD-25T J
OBO5509A | Carbon Resistor 33K ERD-25T J] R109,209 | 0B01683A | Carbon Resistor 15K ERD-25T J
0B09215A | Fail Safe Type Resistor R110,210 | OBOS625A ; Carbon Resistor 220K ERD-25T J
100 RDF25S J] R111,211 | OB05692A | Carbon Resistor 68K ERD-25T J
0B09372A | Electrolytic Capacitor 2.2u 50V 309
0B09137A | Electrolytic Capacitor 22u 16V (LN)| R112,212 0B05621A | Carbon Resistor 120K ERD-25T
0B09333A | Electrolytic Capacitor 4.74 25V (LN)| R1 14,168 | 0B05615A | Carbon Resistor 22K ERD-25T J
0B01272A | Electrolytic Capacitor 100” 25V 169,214
268, 269
atoms Part No. Description
R115,215 | OBO1888A | Carbon Resistor 10K ERD-25T J
308
R167, 267 | 0B01857A | Carbon Resistor 1K ERD-25T J
R303 OBO9305A | Metal Film Resistor 100K SN14K2E
R304 OBO5560A | Carbon Resistor 18K ERD-25T J
C101, 109 | OB01389A | Electrolytic Capacitor 4.74 25V
111,201
209, 211
C102, 202 | 0B09242A | Mica Capacitor 47P 50v J
C103, 203 | OB09262A | PP Capacitor 3000P s50V J
C104, 204 | 0B01913A | Mylar Capacitor 1800P 50V J
C105,106 | 0B01780A | Mylar Capacitor 0.14 50V J
205, 206
302
C107, 207 | 0B05530A | Myiar Capacitor 6sooP 50V J
C108, 208 | OBO5682A | Mylar Capacitor 0.0684 50V J
C110,210 | 0B01804A | Mylar Capacitor 3900P 50V J
C112,212 | OBO1862A | Electrolytic Capacitor 22u 16V
C150, 250 | OB01836A | Electrolytic Capacitor 47yu 10V
C301 OB09363A | Mylar Capacitor 0.011n 50V J
C303 OBO9045A | Mylar Capacitor 0.0274 SOV J
C304 OB09323A { PP Capacitor 560P 100V J
C305 OBO5685A | Mylar Capacitor 0.082u 50V J
C306 0B05583A | Mylar Capacitor 0.033u 50V J
SW301 0B07307A | Rotary Slide Switch F SRZW44N
SW302 0B07308A | Rotary Slide Switch G SRZW84N
CN1 OBO08642A | 6P-T Post
M401 OB08363A | Spark Killer (Japan)
M401 0B08342A | Spark Killer (U.S.A, & Canada)
M401, 402 | OB08445A | Spark Killer (220V Class 2)
M401 OB08240A | Spark Killer (UK & Australia)
M401 OB08240U | Saprk Killer (Others)
F401,402 | 0B08344A | Fuse 200mA T 250V (UK, Australia
& 220V Class 2)
0M04112A | Fuse Label 260mA 250V x 2
(UK, Australia & 220V Class 2) (1 pce.)
OB08349A | Fuse Clip (UK, Australia & 220V
Class 2) (4 pes.)
BA04174A | Lamp P.C.B. Ass’y
OBO7859A | Lamp P.C.B.
0B08155A | Meter Lamp (2 pes.)
Tt

MECHANISM ASS’Y AND PARTS LIST
LOS: ha LO?
Schematic we by
| Seerne | rare. | aacage ntl
Synthesis
OHO3799C
0J04084C
0J03564A
0H03732B
0H03733A
0H03738B
OHO3739A
0H03797B
0H03791B
Top Cover
Bottom Cover
Leg T-H
Volume Knob A
Volume Knob Sleeve A
Volume Knob B
Volume Knob Sleeve B
Front Panel
Power Switch Knob
Escutcheon
Power Switch Knob D
0H03792B
0J04075A
OHO3806A
OHO3800A
0HO03801A
JA03634A
Meter Escutcheon
Handle
Side Panel
(U.S.A. & Canada}
JA03635A
(Japan)
JA03636A
(Others)
JA03637A
(220V Class 2)
JA03638A
(UK)
JA03639A
(Australia)
Volume Knob
Cushion
Caution Label
Pass Label B
Serial Number Plate
BT Screw M4x6 Philips
Binding Head (Black
Chromate)
OHO3296B
OH03781A
OM04101A
0M03551B
0M04104B
OEO0858A
OE00736A
OEOO860A | BT Screw M3x6 Philips
Binding Head (Black
Chromate)
OEO0865A
Binding Head
ST Screw M4x8 Philips
Binding Head
Washer 4mm (Bronze)
Screw M4x6 Philips
Countersunk
Chobert Rivet
OE00897A
OE00914A
OE00891A
0J03644A
Seago = Ao oe
Power Switch Knob Spring
ANN = Ba
Synthesis Mechanism Ass’y
Synthesis Mechanism Ass‘y
Synthesis Mechanism Ass’y
Synthesis Mechanism Ass'y
Synthesis Mechanism Ass‘y
Synthesis Mechanism Ass’y
Washer 4mm (Black Chromate)
BT Screw M3x10 Philips
a’ Schematic
tY | Ref. No.
AO1
01
02
03
04
0S
06
07
08
09
10
11
12
L01
LO2
LO3
LO4
LOS
JA03635A
JA03636A
JA03637A
JA03638A
JA03639A
0J04085C
HA03892A
HA03893A
HA03894A
HA03895A
HAO03896A
HA03897A
0J04090B
0J04091B
BA04138A
BA04137A
BA04141A
BA04139A
BA04140A
BA04147A
0J04086B
0J04087A
0B07253A
OBO7271A
0B07252A
OBO06627B
OBO6626B
OBO6629C
OB06628B
OBO08515A
0J04092A
OEOO860A
OE00857A
OEO0607A
OE00507A
OE00S02A
Porno, | Bwwroton for
JA03634A
Synthesis Mechanism Ass’y
(U.S.A. & Canada)
Synthesis Mechanism Ass’y
(Japan)
Synthesis Mechanism Ass’y
(Others)
Synthesis Mechanism Ass‘y
(220 V Class 2)
Synthesis Mechanism Ass’y
(UK)
Synthesis Mechanism Ass’y
(Australia)
Front Chassis
Rear Panel Ass'y (U.S.A. &
Canada)
Rear Panel Ass’y (Japan)
Rear Panel Ass’y (Others)
Rear Panel Ass’y (220V Class 2)
Rear Panel Ass’y (UK)
Rear Panel Ass‘y (Australia)
Side Chassis L
Side Chassis R
Main P.C.B. Ass’y (U.S.A. &
Canada)
Main P.C.B. Ass’y (Japan)
Main P.C.B. Ass‘y (Others)
Main P.C.B. Ass’y (220V
Class 2)
Main P.C.B. Ass’y (UK &
Australia)
Meter Ass’y
Power Switch Flange
Power Switch Holder
Power Switch (U.S.A. &
Canada)
Power Switch (Japan)
Power Switch (220V Class 2,
UK, Australia & Others)
Power Transformer (U.S.A. &
Canada)
Power Transformer (Japan)
Power Transformer (Others)
Power Transformer (220V
Class 2, UK & Australia)
Insu-lock
P.C.B. Supporter
BT Screw M3x6 Philips
Binding Head (Black
Chromate)
BT Screw M3x6 Philips
Binding Head
Screw M3x8 Philips Pan
Head (3A)
Nut Hex. M3
Screw M3x5 Philips Pan Head
ee ee a ee

6.2. Synthesis Mechanism Ass’y (A01)
LO2 O1 07 LO5 08 O9
Fig. 6.2
16

6.3. Rear Panel Ass’y (B01)
Others
Fig. 6.3
6.4. Meter Ass’y (B02)
7

Schematic
Ref. No. Part No.
Description
, Schematic
O'ty Ref. No.
Part No.
Description
ra
HA03892A
HA03893A
HA03894A
HAO3895A
HA03896A
HA03897A
OB08533A
0B08219B
OBO8093U
OB08348A
OBO8666A
0B08037U
OB08351A
0B08325U
OH03798F
0B08362A
0J04088A
0B07312A
0B07311A
0B03920B
0J03663C
OM03946A
0M03794A
OM03796A
OM03797A
OM03955A
0B07092U
OM03700A
OMO3959A
OM03798A
OM03844A
QM03705A
OFO1071A
OEO0860A
QE00174A
0E00507A
OE00594A
OBO08583A
OE00593A
0E£00172A
Rear Panel Ass’y (U.S.A. &
Canada)
Rear Panel Ass’y (Japan)
Rear Panel Ass’y (Others)
Rear Panel Ass’y (220V
Class 2)
Rear Panel Ass’y (UK)
Rear Panel Ass’y (Australia)
Power Cord (U.S.A., Canada
& Others)
Power Cord (Japan)
Power Cord (220V Class 2)
Power Cord (UK)
Power Cord (Australia)
Cord Bushing C (U.S.A.,
Canada, Japan, 220V
Class 2 & Others)
Cord Bushing 4K-K (UK)
Cord Bushing E (Australia)
Rear Panel
2P Pin Jack
Volume Holder
Volume 50 kQ (B)
Volume 10 kQ (B)
Ground Terminal
Switch Cover C (Except
Others)
Voltage Selector Lock Plate
(Others)
Voltage Seal 100V (Japan)
Voltage Seal 220V (220V
Class 2)
Voltage Seal 240 (UK &
Australia)
Voltage Seal 120V/220-240V
(Others)
Voltage Selector (Others)
Ground Mark Label
File Number Label B
(U.S.A. & Canada)
Nakamichi Label (Japan)
Power Cord Label! (UK)
Power Cord Label (Australia)
Free-up Belt
BT Screw M3x6 Philips
Binding Head (Black
Chromate)
Earth Lug B-5
Nut Hex. M3
Screw M3x8 Philips Binding -
Head (Bronze)
Plastic Rivet
Screw M3x6 Philips Binding
Head (Bronze)
Washer 3mm Toothed Lock
*; Depens on the versions.
BPA nNNNA = | uo
18
BA04147A
0B08700D
0B08199A
0503456B
0J03418A
0J03455C
BA04174A
0J04093A
0B08701A
0J04089B
OEO0505A
OE00859A
0E00612A
Meter Ass’y
Meter
Meter Band
Meter Cushion
Lamp House
Meter Holder
Meter Lamp P.C.B. Ass‘y
Filter Cover
6P-H Connector 165
Insulator (Fiber)
Screw M3x6 Philips
Countersunk
BT Screw M2.6x6 Philips
Binding Head
Screw M3x6 Philips Pan Head
(2A)
Be aM BAe NA AN

7. BLOCK DIAGRAM
Osc. ~
Cape eS coor oc cata ta 4 i
| 1
Input ! Tl
Level Master I |
* | |
Line MPX Subsonic | fe eh J
wa ! ie
I i
q VCR
!
Se Ey ae a et ee ey ? a Output
B Mod P
VCR: Voltage Control Resistor fof Line
Cc Output
Ls
Seen pat nateatye SaaS os o
=a
I
t
! I
- ! |
yes gs —4——ssC eS PR |
|
I
Play PB Amp. +
Input
= 8
Mode
ct
. A ~———___
Filter Switch:
1. Subsonic
2, Ott
3. MPX
4. Subsonic / MPX
Mode Switch:
a
A. Cal. 400Hz
B. Record A © Cot,
C. Pass Bo Reo.
0. Piaybock c Output
Fig. 7
U401B 19 418 20 22 24
— ——— + O O O O _—_ ore ie
au+
ra
Hy io
if .
4
3
5 <4
—_— — O _o— —O- O
8 13 15 16 17
Fig. 8.1 IC U401B
Output A +V
inverting Input A Output B
Non-Inverting Inverting
Input A input B
-V Non- Inverting
Input B
Fig. 8.2 Operational Amp. IC 4558
19