Nakamichi PS-100, SF-100, LA-100, BA-150, MB-150 MC Service Manual

Service Manual

Nakamichi

Nakamichi

BlackBox Series

PS-100 Power Supply

SF-100 Sub-sonic Filter

LA-100 Line Amplifier

BA-150 Bridging Adaptor

MB-150 MC Booster Amplifier

EC-100 Electronic Crossover

MX-100 Microphone Mixer

CONTENTS
1.	PS-100 Power Supply ...........................................................................................................................................	1
	General, Mute Signal, Specifications, Schematic Diagram, Mounting Diagram
	and Parts List, Mechanism Ass'y and Parts List
2.	SF·100 Sulnonic Filter ........................................................................................................................................	5
	General, Specifications, System Diagram, Schematic Diagram,
	Mounting Diagram and Parts List, Mechanism Ass'y and Parts List
3.	LA·100 Line Amplifier .........................................................................................................................................	8
	General, Specifications, System Diagram, Schematic Diagram,
	Mounting Diagram and Parts List, Mechanism Ass'y and Parts List
4.	BA· 150 Bridging Adaptor .....................................................................................................................................	11
	General, Specifications, System Diagram, Schematic Diagram,	-
	Mounting Diagram and Parts List, Mechanism Ass'y and Parts List
5.	MB-150 MC Booster Amplifier .............................................................................................................................	14
	General, Specifications, System Diagram, Schematic Diagram,
	Mounting Diagram and Parts List, Mechanism Ass'y and Parts List
6.	EC-100 Electronic Crossover ................................................................................................................................	17
	General, Specifications, System Diagram, Schematic Diagram,
	Mounting Diagram and Parts List, Mechanism Ass'y and Parts List
7.	MX.100 Microphone Mixer ..................................................................................................................................	20
	General, Specifications, System Diagram, Schematic Diagram,
	Mounting Diagram and Parts List, Mechanism Ass'y and Parts List

1. PS-100 POWER SUPPLY

General

PS-100 Power Supply

PS-100 is a regulated power supply unit designed to be a power supply for the BlackBox Series (the rated output current: ±200 mA).

Although PS-100 is provided only with one output termi·

nal, two input/output terminals on the other units of the

BlackBox Series make multiple connection of PS-100 possible.

To prevent noise signal generation on switching ON/OFF the power supply, PS· 100 produces a mute signal, muting

output terminals of each unit furnished with a muting circuit.

Refer to Table 1 showing how many units of the Black· Box Series can be driven by a single PS-100.

Mute Signal

Mute signal is muted for a certain period of time to prevent transient noise when power is ON or OFF.

Power ON

Transformer output is rectified through diode 0403 and smoothed by capacitor C408. Therefore, positive poten· tial appears at C408 (transistor 0411 base). Accordingly, 0411 is in the cutoff state. C409 (22 µF) is charged with negative potential through R414 (1 M.n), therefore at the level where the voltage across C409 exceeds Vbe (base· emitter voltage) of 0412, 0412 turns from OFF to ON.

As a result, 0413 turns on and the mute signal is changed from+ V to -10 V, releasing the mute state.

(The mute time depends on C409 and R414 after power is ON.)

Power OFF
Transformer output becomes zero and so C408 is charged
with negative potential through R415. At the level where
the voltage across C408 exceeds Vbe of 0411, 0411 turns
from OFF to ON and C409 is quickly discharged. Thus,
0412 is cut off and 0413				is also	cut off.	Therefore
the	mute signal	becomes	+ V (i.e.		mute state).		0402
acts	to prevent	+ V from	being discharged			easily	when
power is OFF.
Specifications
Maximum Power Consumption .				20 VA
Output Voltage ............				± 10 V
Rated Output Current . . . . .			.	. . ± :200 mA
Dimensions ..............				7-1/2(W) x 2-3/S(H~ x
				3-15/16(0) inches
				190\Wl x60\Hl x 9910) mm
Weight .................				3.5 lb, 1.6 kg

1

Table 1 Combinations of Units Driven by a single PS-100

~

PS-100

SF-100

LA-100

BA-150

MB-150

EC-iOO

MX-100

Power

Sub-sonic

Line

Bridging

MC Booster

Electronic

Microphone

Supply

Filter

Amplifier

Adaptor

Amplifier

Crossover

Mixer

Roting

4

VA

0.5 VA

0.5 VA

1 VA

2 VA

t VA

2 VA

c±200mAl

t±25mAl

tt.25 rnAl

(±50 mAI

(±100 mAl

(±50 mAl

1±100mAl

1

0

0

0

0

'

2

0

0

0

0

3

0

0

0

0

Combination

4

0

0

0

0

5

0

0

0

6

0

0

0

7

0

0

Maximum

,

Drivable

8

8

4

2

4

2

Number

of Units

Schematic Diagram

POWER SUPPLY P.c.a.

..,

o•o•

Uo2l'

""

~!

~!

"""' ~~

+1ov

-,

SIR...

,.,,

I

o~

;',~

J~::~

>S<••o

~;

;i;~

¥5

VERSION

.......

<.l~

'I

~

..

.~tg~.

U.S.A. /CANADA

: .

~~

I

;:.,

~~

0407

'"~"'

L __

2

o~o•

$843'

rELIROPEVERs10N- -

- -

-.::--;: --::- 1

I

M)

OP~

14V

1

,,,,,~,,,,,,,,,

I

I

.,,,,.._~

I

I

I

I

I

I

I

I

I

I i.;;~'

•••

,~

I

L----------~~-~~J

Fig.

1.1

Notes: 1.

Fuses marked with * 1 are not incorporated in the U.S.A. version.

2.

The type of spark killer marked with

•2 differs in some countries.

2

·~·<)

·~··- . .

Mounting Diagram and Parts List
~~~~~~~~~~~~~~~~~~~~~....
0		-I~
		or~
	0401	•	0
		0	'
	SIRBA	y	•
.- --1
I	I	I
I	,\ 1,i
I	'1•I	•
I	l> I
I.-~ I
I	'( I
I	I
L--_J

~~

0	0	0	0	0	0	0	c 0	0
	C.T.		AC	MUTE		GND	+

\.

Fig. 1.2

Schematic

I Part No,

Description

Schematic

Part No.

Description

Ref. No.

Ref. No.

i BA03855A

PS-100 P.C.B. Ass'y

C405

OB01391A

Electrolytic Capacitor

IOB07720A

Power Supply P.C.B.

220µ

25V

C406,407

OB01502A

Electrolytic Capacitor

Transistor

2SA733

0401,407

OB06013A

330µ

16V

408,410

C408

OB01780A

Mylar Capacitor

0.1µ

50V J

411,412

Transistor

250235 (YI

C409

OB05820A

Electrolytic Capacitor

0402

OB01823A

22µ

16V M

2SC945

0403,404

0801872A

Transistor

(MS)

405,409

OJ035978

Heat Sink

(1 pee.)

413

'

OE00607A

Screw M3x8 Philips Pan Head

0406

I0806011A

Transistor

2SB435

(3AI (4 pcs.I

0401

I0806088A

Silicon Diode

S1RBA

OE00507A

Nut Hex. M3

(2 pcs.}

Silicon Diode

151555

0402,403

OB01909A

Z0401

IOB06063A

Zener Diode

YZ040B

R401,409

OB01781A

Carbon Resistor

1K

ER0-25V J

419

Carbon Resistor

4.7M

ER0-50T J

R402,408

OB05824A

R403

OB05673A

Carbon Resistor

5.6K

ER0-25V J

R404

OB05664A

Carbon Resistor

3.9K

ER0-25V J

R405,411

OB05746A

Carbon Resistor

1

ER0-25V J

R406

OB01793A

Carbon Resistor

3.3K

ER0-25V J

R407

OB05826A

Carbon Resistor

11K ER0-25V J

R410,418

OB01833A

Carbon Resistor

10K

ER0-25V J

R412

OB05596A

Carbon Resistor

220K

ER0-25V J

R413

0805563A

Carbon Resistor

56K

ER0-25V J

R414,416

0805564A

Carbon Resistor

1M ER0-25V J

R415

Carbon Resistor

OB05674A

820K

ER0-25V J

R417

0801921A

Carbon Resistor

330K

ER0-25V J

C401,403

0801401A

Electrolytic Capacitor

470,u

25V

C402,404

0B01272A

Electrolytic Capacitor

100µ

25V

3

Mechanism Ass•y and Parts List

L03

05

L04

07

13

06

11

Fig. 1.3

Schematic

Part No.

Description

Q'ty

Schematic

Part No.

Description

Q'ty

Ref. No.

Ref. No.

PS-100 Mechanism

, 1

HA03697C

Main Chassis PS Ass'v

1

12

OH03437A

Rubber Foot

4

01

OH03509A

Upper Cover PS

1

13

0808361A

Spark Killer

125 V {R+ Cl

1

02

0M03799A

Caution Label G

1

0808363A

Spark Killer

125V{R+C)

,

OM03800A

Caution Label H

,

0808342A

Spark Killer

125V{R+C)

,

03

BA03855A

PS-100 P.C.B.Ass'y

1

0808240A

Spark Killer

250 V {R + C)

1

04

0808161U

Fuse 630 mA

2

0807096U

Spark Kiffer

{C)

1

05

0806567A

Power Transformer 100-120 V

1

L01

OE00713A

Screw M3x6 Philips Tr.uss Head

4

0806568A

Power Transformer 220-240 V

1

L02

OE00606A

Screw M3x6 Philips Pan Head

3

06

0808025U

5P Terminal

1

(3A)

07

0808355A

4P DIN Socket

1

L03

OE00538A

Screw M4x5 Philips Binding

2

08

OB07172A

Power Switch

1

Head

0807092A

Power Switch

1

L04

OEOQ594A

Screw M3x8 Philips Binding

2

09

0808037A

Cord Bushing

1

Head

0808351A

Cord Bushing

1

LOS

OEOQ714A

Screw M2.6x6 Philips Birlding

2

0808325A

Cord Bushing'

1

Head

10

0808350A

Power Cord

1

L06

OE00651A

Washer 2.6 mm (plastics)

2

08082198

Power Cord

1

L07

OE00593A

Screw M3x6 Philips Binding

2

0808348A

Power Cord

1

Head

0808149U

Power Cord

1

LOB

OE00157A

Washer 3 mm (plastics)

2

Notes: 1. 02, 08, 09 and 10 differ in versions.

2. 04 (fuse) is not incorporated in the U.S.A. version.

4

2. SF-100 SUB-SONIC FILTER

General

In disc record reproduction, low-frequency resonance of a tone arm and rumbling of a turn table exist at about 10

Hz and their peak level ranges approximately from 5 to 15

dB.

SF-100 is an active filter to eliminate these noises.

The unit is designed so that no low frequency sound recorded on disc records is sacrificed and no change in tones is effected.

To compensate the personal feeling of insufficiency in low frequency sound caused by the insertion of the Sub-sonic Filter, a Low Boost Switch is provided which can boost

signal approximately by 5 dB at 30 Hz.

With both of the Filter Switch and Low Boost Switch

Specifications

Maximum Power Consumption .	0.5 VA
Current Consumption ...	25mA
Total Harmonic Distortion	less than 0.005% (50 Hz -
	20 kHz, 1 V Output)
Frequency Response ... .	40 Hz - 100 kHz± 0.5 dB
Sub-sonic Filter ........ .	10 Hz: -50 dB,
	-40 dB (with Low
	Boost)
Low Boost ..... .	30 Hz: + 5 dB
Signal-to-Noise Ratio	better than 110dB (IHF-A
	Network)
Mute Function	Furnished
Dimensions ..	7-1/21WI x 2·3/81HI x
	4-1/16(0} inches
	190IWI x60IHJ x 1031Dlmm
Weight ................ .	2.7 lb, 1.2 kg

turned OFF, the input signal directly appears on the output terminals without passing through the Sub-sonic

Filter.

The output of the twin-T filter is amplified by Amplifier

2, while the output of the amplifier is positively fed back through C2 and R2 to compensate the level reduction in the range of 20-50 Hz.

Further, to increase the attenuation below 5 Hz, the filter load impedance is lowered with R4 , and the improvement of characteristics can be realized by changing impedance of every device.

In addition, a high pass filter is incorporated in the input side of Amplifier 1 to ensure an ideal sub-sonic filtering characteristics.

System Diagram

Input						Output
	'>-~4~.+-.-fl-.-'-1HA,,,...z(>..J..-~~
	C1	CJ	!
		"	I
			I
	I		I
	L ______ _J			'"
	Twi"	T F'olter
				'"'
					Filter
			Mute		Switch

Fig. 2.1

Schematic

Part No.

Description

Schematic

Part No.

Description

Ref. No.

Ref. No.

BA03849A

SF-100 P.C.B. Ass'y

R114,115

OB05562A

Carbon Resistor

47K

ERD-25V J

0807719A

SF P.C.B.

119,214

215,219

ERD-25V J

0101,102

OB06062A

Transistor

2sc1222 121

R116,216

OB05678A

Carbon Resistor

560

201,202

2SA733

R117,118

OB05567A

Carbon Resistor

33

ERD-25V J

0103,104

OB06013A

Transistor

217,218

50V J

203,204

C101,201

OB05682A

Mylar Capacitor

0.068µ

0105,205

OB01872A

Transistor

2SC945 ILi

C102,202

OB01863A

Electrolytic Capacitor

0101.102

0801909A

Silicon Diode

1S1555

3.3µ

16V

103,201

C103,105

OB05844A

Mylar Capacitor

0.33µ

50V J

202,203

203.205

sov J

R101,201

OB05700A

Carbon Resistor

470K

ERD-25V J

C104.204

OB05832A

Mylar Capacitor

0.018µ

R102,202

0805564A

Carbon Resistor

1M ERD-25V J

C106,206

OB05639A

Electrolytic Capacitor

R103,203

OB05563A

Carbon Resistor

56K

ERD-25V J

1.5µ

35V M

R104.204

OB05608A

Carbon Resistor

220

ERD-25V J

IMS)

R105,205

0B01789A

Carbon Resistor

330

ERD-25V J

C107,108

OB05884A

Electrolytic Capacitor

R106,206

OB05664A

Carbon Resistor

3.9K

ERD-25V J

207,208

470µ

10V

R107,207

0B01564A

Carbon Resistor

82K

ERD-25V J

OB07167A

Push Switch

11 pee.>

R108,109

0B01921A

Carbon Resistor

330K

ERD-25V J

CN1

OB08182A

6P-T Post

208,209

ERD-25V J

CN2

OB08236A

4P-T Post

A110,210

OB01795A

Carbon Resistor

4.7K

A111,211

OB01902A

Carbon Resistor

68K

ERD-25V J

R112,212

OB05569A

Carbon Resistor

47

ERD-25V J

R113,213

0B05565A

Carbon Resistor

1.2K

ERD-25V J

5

Schematic Diagram

S.f. P.C.B.

R117

CN-2

"°

POWER

m

N~

,,>

"

INPUT

N

CN-1

cio1

Rl04

"

0.06SJ

"'

~~

0

ILN'UT

-oO"

""o•

,,

u;

Zl•50KJ1'

,

oo

..

""

~

;:;~

.

1.5~

Rn5.,,

"'

e~

CIOS

CN-1

R102

35V T

l"'"'"'

,

'"

(;<i

u•

•

•o

''"

LEFT

C103

RH 1

""

0.33J

'"

2SC945

POWER

OUTPUT

"

RIOS

>

330K

;!:~

••

'"

".

oO

CN•1

"

·~:;:

;1jS

C

N·Z

OUTPUT

' (

'

Zo•560.n

C

N-2

Rl•10KQ

I

L

"ru

l;i119

MUTE

I

"'

-1-2.,

J,

1S15!S

~1a=

":i 8

R2•7

,.

~I~

(/}I~;;:

9.av

I

I~

I

ILN'UT

ow

CN·h

lc201

3t

10

~

~

Zl•!50Kfl

,~

I -

"

'"

CN-h

'~'

'

•

I

~ u2

~

RIGHT

I

l-··

I

C205

~

I

.

I

I

RZOS

I

"

I

OUTPUT

v16

CN·f1

Zo•!560n

' u'

"

•9.SV

R2•9""~

Rl~10Kfl

0203

Fig. 2.2

Mounting Diagram and Parts List

Fig. 2.3

6

Mechanism Ass'y and Parts List

LOl

L04

05

L05

08

03

09 ---- j

10--~:1

L10

L03~/

M-------10

L02

Fig. 2.4

Schematic

Part No.

Description

O'ty

Schematic

Part No.

Description

O'ty

Ref. No.

Ref. No.

SF-100 Mechanism

L03

OE00157A

Washer 3 mm (plastics)

7

01

L04

OE00606A

Screw M3x6 Philips Pan Head

2

OH03507A

Upper Cover SF

1

l3AI

02

8A03849A

SF-100 P.C.B. Ass'y

1

LOS

OE00612A

Screw M3x6 Philips Pan Head

5

03

OJ036548

Front Chassis

1

l2AI

04

JA03061A

Push Button Ass'y

2

LOG

OE00507A

Nut Hex. M3

1

05

OJ03440A

Switch E Block Base

1

L07

OE00037A

Earth Lug B-5

1

06

08082908

6P Pin Jack

1

LOB

OE00594A

Screw M3x8 Philips Binding

5

07

OJ03277A

Metal Seat Nut

2

Head

08

0808355A

4P DIN Socket

2

L09

OE00714A

Screw M2.6x6 Philips Binding

4

09

OH03508B

Main Chassis SF

1

Head

10

OH03437A

Rubber Foot

4

LIO

OE00651A

Washer 2.6 mm (plastics)

4

L01

OE00713A

Screw M3x6 Philips Truss Head

4

L02

OE00593A

Screw M3x6 Philips Binding

2

Head

7