Nakamichi PA-7, PA-7E Service Manual

Service Manual

Nakamichi

Nakamichi

PA-7

PA-7E

Power Amplifier

CONTENTS

1.	General		............... • ..	, ......................... , . . • .				.	. . . • . .	. . . . . • . . .	. . . . .	1
2.	Parts Location for Electrical Adjustment				. . . . . . . .	. . . . . . . . . . .	. . . . . . . .	.	. . . . . .	. . . . . • . . .	• . . . .	2
3.	Electrical . . . .Adjustments . . . .			. . . .	. . . . . . . .	. . . . . • . . . . .	• • . . . . . .	.	. . . • . •	. . . . . . • . .	. . . . .	2
	3.	1.	Preparation for Adjustment		. . . . . . . . .	. . . . . . . . . .	. . . . . . . .	.	. . . . . .	. . . . . . . . .	. . . . .	2
	3.	2.	DC Balance Adjustment . . .		• . . . . . . . .	. . . . . . . . . . .	. . . . . • .	.	. . . . . .	. . . . . . . . .	• . . . .	2
	3.	3.	Idling Current Adjustment .		. . . . . . . . .	. . . . . . . . . . .	. . . . . . .	.	. . . . . .	. . . . . . . . .	. . . . .	2
4.	Mechanis.rn Ass'y and Parts List . .			. . . .	. . . . . . . . .	. . . . . . . . . . .	. . . . . . .	.	. • . . . . .	. . . . . . . .	. . . . .	3
	4.	1. . . . . .	Synthesis . . .	. . . .	. . . . . . . . .	. . . . . . . . . . .	. . . . . . .	.	. . . . . . .	. . . . . . . .	. . . . .	4
	4.	2.	Handle L Ass'y (AOl)	. . . .	. . . . . . . . .	. . . . . . . . . . .	. . . . . . .	.	. . . . . . .	. . . . . . • .	. . • . .	4
	4.	3.	Handle R Ass'y (A02)	. . . .	. . . . . . . . .	. . . . . . . . . . .	. . . . . . •	.	. . . . . . .	. . . . . . . .	. . . . .	4
	4.	4.	Front Panel Ass'y (A03) ..............			, . . . . . . . • . . . . . .		•	. . . . . . .	• . • . . . . . .	. . . .	4
	4.	5.	Rear Panel Ass'y (A04)	.............		, . . . . . . • . .	. . . . . • .	.	. . . . . . .	. . . . . . . . .	. . . .	5
5.	Mounting Diagrams and Parts List			..... , . . . . . . . . . . . . . . . . . . . . . . . . . .					. . . . . . . . . . . . . . . . . . . .			5
	5.	1.	Clipping LED P.C.B. Ass'y . .		. . . . . . . .	. . . . . . . . . . .	. . . . . . . .		. . . . . . .	. . . . . . . . .	. . . .	5
	5.	2.	Power LED P.C.B. Ass'y ...........			• , ..... • ....	•• , . . • .		. • . . . . .	. • . . • . . . .	. . . .	5
	5.	3.	Limiter P.C.B. Ass'y . .	. . .	. . . . . . . . .	. . . . . . . . .	. . . . . .		. . . . . . . . . . . . . . . . . . . .			5
	5.	4.	Amp. L P.C.B. Ass'y . .	. . .	. . . . . . . . .	. . . . . . . . . . .	. . . . . . . .		. . • . . . .	. . . . • . . . .	. . . .	6
	5.	5.	Amp. R P.C.B. Ass'y . .	. . . .	. . . . . . . .	. . . . . . . . . . .	. . . . . . . .		. . . . . .	• . . . . . . . . .	. . . .	7
	5.	6.	Protector L P.C.B. Ass'y . .		. . . . . . . . .	. . . . . . . . . . .	. . . . . . . .		. . . . . . .	. . . . . . . . .	. . . .	7
	5.	7.	Protector R P.C.B. Ass'y . .		. . . . . . . . .	. . . . . . . . . . .	. . . . . . . .		. . . . . . .	. . . . . . . . .	. . . .	7

6.	Schematic Diagram . . . . .	. . . . . . . . . . . . . . . . . . • . .	. • . . . . . . .	. . . . . . . . . .	. . . • . . . . . . . . . . . . .	8
7.	Wiring Diagram . . . . . . .	. . . . . . . . . . . . . . . . . . . . .	. . . . . . . . .	• . . . . . . . . .	• . . . . . . . . . . . . . . . .	9
8.	Block Diagram	. . . • . . . . . . . . . . . . . . . . .	. . . . . . . . .	. . . • • . . . . .	. . . . . . . . • . . . . . . . .	9
9.	Specifications . . . . . . . .	. . . . . . . . . . . . . . . . . . . . .	• . . . . . . . .	. . . . . . . . . .	. . . . . . . . . . . . . . . . .	10

1.GENERAL

1.1.Voltage Selector

Voltage selector is installed on the rear panel for Other version of the N akamichi P A-7.

This voltage selector can select 110 V, 120 V. 220 V or 240 V at customer's dillpo$3!,

1.2. Packinrt Materials, Owner's Manual and Power Cord

Part No.	Description	Q'ty
OF03875B	Outer Carton PA·7	1
OF03876C	Outer Carton P A-7E	1
OF03869B	Inner Carton PA·7	1
OF03870B	Inner Carton PA-7E	1
OF03877B	Packing	2
OD04531A	Owner's Manual English	1
OD04530A	Owner's Manual English/German/French	1
OB90137A	Power Cord P A·7 (U.S.A. & Others)	1
0B90139A	Power Cord PA-7 (Australia)	1
OB90138A	Power Cord PA-7E (220V Class 2)	1
OB90154A	Power Cord PA·7E (Switzerland)	1
OB90140A	Power Cord PA-7E (UK)	1
OF03887A	Power Cord Band	1

2.PARTS LOCATION FOR ELECTRICAL ADJUSTMENT

flI

	cri	cri
	u	u
	0..:	a.:
	_J	a::
	ci.	ci.
		E
	E
	<{	<{

G

0

VR!OJ ----

VR!OZ----

T p	TP201
	TP?02

Fig. 2

3.ELECTRICAL ADJUSTMENTS

3.1.Preparation for Adjustment

(1)Insert shorting pins into the Input Jacks.

(2)Remove loads of the speaker tennlnals.

(3)Before starting adjustment, allow twenty minutes or more after the power is turned ON.

3.2.DC Balance Adjustment

(1)Connect a DC voltmetr to the L (R) channel ll(>eaker terminal.

(2)Adjust VR101 (VR201) to obtain 0 ±100 mV on the DC voltmeter.

3.3.Idlinti Current Adjustment

(1)Connect a DC voltmeter between TP101 and TP102 (TP201 and TP202) on the Amp. L (R) P.C.B. Ass'y.

(2)Adjust VR102 (VR202) to obtain 40 mV on the DC voltmeter (idling current: 40 mA).

(3)Repeat 3.2 and 3.3 one or two times.

(4)Remove shorting pins from the Input Jacks,

4.MECHANISM ASS'Y AND PARTS LIST

'""'"'"'"'""

----· ~--~--~-+---

___.,.,..._.___

Schematic I

hrt NJ;---~::lp<Wn

Schematic

Part No.

Description

Q'ty

Q'ty

Ref. No.

Ref. No.

; Synthesis

AOl

HA04832A

Handle L Ass'y

1

i Serial No.: B20601001-

Serial No.: B20601001 -

1

1

01

HA04832A

Handle L Ass'y

01

0H04631A

Handle L

02

HA04846A

Front Panel Ass'y PA·7

l

02

OJ05006A

Vinyl Chloride Plate A

2

HA04847A

Front Panel Ass'y PA-7E

1

03

OH04655A

I Vynil Chloride Plate B

1

03

BA05688A

Clipping LED P.C.B. Ass'y

2

LOl

OE03310A

M4x6 tlJ Binding (Black Chromate)

2

04

BA05687A

Power LED P.C.B. Ass'y

1

05

HA04833A

Handle R Ass'y

1

A02

HA04833A

Handle R Ass'y

1

06

OJ04989B

! Front Chassis

1

Serial No.: B20601001 -

07

0B71003A

: Power Switch

1

08

OJ05048A

I P.C.B. Spacer

4

01

OH04632A

Handle R

1

09

BA05754B ! LimiterP.C.B. Ass'yPA-7

1

02

OJ05006A

Vinyl Chloride Plate A

2

(U.S.A.)

03

OH04655A Vinyl Chloride Plate B

BA05755B

Limiter P.C.B. Ass'y PA·7

1

LOl

OE03310A

M4x6 Gl Binding (Black Chromate)

11

OH04633D

(Australia & Others) & PA·7E

1

:!~:::~!! Front Panel Ass'y PA-7E

1

Heat Sink A

10

OH04634D

Heat Sink B

1

A08

Front Panel Ass'y PA·7

1

12

OJ04990A

Side Chassis

2

Serial No.: B20601001 -

13

OJ05025A

Stud

2

14

BA05684B

Am.p, L P.C.B. Ass'y

1

01

OH04618B

Front Panel PA·7

1

15

OM04377B

Caution Label

1

OH04619B

Front Panel PA-7E

1

16

OH04629B

! Top Cover

l

02

HA04849A

Power Switch Button Ass'y

1

17

OJ05011A

i

Cushion A

6

03

OJ05000B

Spring

1

18

OJ05055A

i

Cushion B

1

04

OH04652B

Guide

1

19

OB12253A

l

Diode Bridge 15G4B41

2

05

OH04653B

Illuminator

l

20

OJ05047B

Ground Plate Collar

1

06

OH04651A

Lens

2

21

OJ04992C

Ground Plate

1

07

OJ05005A

P.C.B. Cushion

2

22

OJ05003A

i

Center Stud

1

23

0B40328A

Electrolytic Capacitor

4

33000µF lOOV

24

OB50046B

Power Transformer 120V

l

PA-7 (U.S.A.)

OB50048B

Power Transformer 220/240V

1

PA-7 (Australia) & PA-7E

1

OB50049A

Power Transformer 120/220-240¥

PA-7 (Others)

1

25

OH04650A

!

Bottom Chassis

26

Q,J05009A

i Leg T-D

4

27

HA04845A ; Rear Panel Ass'y P A-7

1

(U.S.A.)

1

HA04843A

Rear Panel Ass'y PA-7 (Australia)

HA04842A

Rear Panel Ass'y PA-7 (Others)

1

HA04844A

Rear Panel Ass'y PA·7E

1

28

BA05685B

Am.p. R P.C.B. Ass'y

1

29

OH04671C

Heat Sink D

1

30

OH04635D

Heat Sink C

1

31

OB08515A

Insu·Lack

20

32

BA05980A

Protector L P.C.B. Ass'y

1

33

BA05981A

Protector R P.C.B. Ass'y

1

L01

OE00745A

Bolt M4x10 Hex. Socket Head

8

(Black Chromate)

L02

OE00985A

M3x6 ffi Binding (Black Chromate)

16

L03

OE03283A

ST 3x6 $Binding

7

OE03220A

(Black Chromate)

L04

ST 3x?.> $Countersunk

2

L05

OE00857A

BT 3x6 ffi Binding

2

L06

OE03298A

ST 4x 14 $Binding

18

OE03289A

(Black Chromate)

L07

M4x 12 f'.DBinding (Bronze)

8

LOS

OE03030A

M3x6 0 Binding (Nickel)

2

L09

OE00713A

M3x6 ©Truss

(Bronze)

9

LIO

OE03290A

M4x15 $Binding (Bronze)

2

Lll

OE03299A

Nut Hex. M4

1

Ll2

OE03287A

M4x6 $Bind.Ing (Gold)

8

L13

OE03296A

M4x4 $Binding (Black Chromate)

12

L14

OE00907A

ST 4x8 f:BBi.ndi.ng (Black Chromate)

8

L15

OE03286B

Washer 6mm (Black Chromate)

4

Ll6

OE03291A

Nut Hex. MS (Black Chromate)

4

L17

OE00972A

1

Nut Hex. M3 (Nickel}

2

Ll8

OE00594A

M3x8 0 Binding (Bronze)

2

L19

OE03034A

M4x8 $Binding (Nickel)

3

L20

OJ05063A

Fiber Washer 0. 5T

8

4.5. Rear Panel A.u"Y (A04)

04

07

'\

LOS

L07 \

\\

'\

\ L04

04

Fia. 4.5

	- .		.		Part No.	Description		Q'ty
			o.
		A04			HA04845A	Rear Panel Au"Y P A-7		l
				IHA04843A		(U.S.A.)
						Rear Panel Au'>' PA·7 (Australia)		1
					HA04842A	Rear Panel Au'y PA•7 (Otheu)		l
					HA04844A	Rear Panel A.u'YPA·7E		1
						Serial No.: B20601001 -
	01				0B90093A	Fuse Holder PA-7		1
						(U.S.A. & Others)
					0B90094A	Fuse Holder P A·7 (Australia)&:		1
						PA-7E		1
	02				OB90118A	Fuse lOA PA·7 {U.S.A. &
						Others)		1
					OB90120A	Fuse T5A PA·7 (Australia) &
						PA-7E		2
	03				OB81364A	Pin Jack
	04				OB81365A	Speaker Terminal		2
	05				OJ05029A	Lea T·A		4
	06				OH04624D	Rea.rPanelPA-7 (U.S.A. &		1
						Australia)		l
					OH04660I>	Rear Panel PA·7 (Others)
					OH04625D	Rear Panel PA-7E		1
	07				OB90092A	AC Inlet PA·7 (U.S.A.)		1
					0B90087A	AC Inlet PA-7 (Australia&:		1
						Others) & PA·7E		l
	08				0B70049A	Voltaae Selector PA-7 (Others}
		LOl			OE00818A	M3x8 S Binding (Black Chromate)		2
		L02			OE03058A	M4x8 €1 Binding (Black Chromate)		1
		L03			OE03313A	BT 4x8 Gl Pan (Black Chromate)		4
		L04		-		Speaker Terminal Nut		8
		L05		-		Pin Jack Washer		2
		LOG		-		Pin Jack Nut		2
		L07		-		Fuse Holder Washer		1
		LOS		-		Fuse Holder Nut		1
		L09			OE00078A	Washer 4mm Toothed Lock		1
		LlO			OE00506A	Nut Hex. M4		1

4.1. Synthesis

01

!A01l

L02

Fie. 4.1

4.2. Handle L Au'Y (AOl)

LOI

	·~
	·u\,
	\
	\
	01
27	Fil. 4.2
(A04l
4.3.	Handle R Au'Y (A.02)

L01

\

\

\

22

.13

~3

Fig. 4.3

4.....~ ~ontPanel AN'Y (A03)

07

\ \04

\z 'O!

'ot

Fil. 4.4

5.MOUNTING DIAGRAMS AND PARTS LIST

Notes: L	Mounting diagram shows a dip side view of the printed circuit board.
2.	Diode is 1SS53, 181555, or lSSl 76 unless otherwise specified.
3. Abbreviation for part name:
	TR -Transistor, SiD - Silicon Diode, ZD - Zener Diode
	RK -	Carbon Resistor, RM -	Metal Film Resistor, RF -	Fail Safe Type Resistor. RC - Cement Resistor
	CE -	Electrolytic Capacitor, CM - Mylar Capacitor, CC -		Ceramic Capacitor, CP -PP Capacitor,
	CT-Tantalum Capacitor, CFFilm Capacitor, C -Mica Capacitor
5.1. Clipping LED P,C.B. An'Y			5.2. Power LED P.C.B. Ass'Y

	0
	AoHQ				<>- .! ...()
					.~~
			,,		v~6~0
						"
	Fig. 5.1
					0	"'
					""	"
					..·t~"
						"

;;;:C',-Y

; ..··

;;.,

...a~~N.

-'

i:(-V

w

-'

Iiif~.-V

...

i(ii). N

~

F'hf. 5.2

o---d'\;>..................------w.--......		------~<;> : 0
F4~,Z	lt41>1 .6 t HIW'	A.C t.J•t

	ffilQ•	R~OJ	6.$ 10\11
o----	<S'\.P~•--~--	~~_.____,,,,w~.~----		~~------	~~--	o
	tll0:$
o--	<r\;p>--e--.------	~------	'llW~.-~----	~~~--	~-'"'~~--	o

F'ii. 5.3