Nakamichi Cossette Deck- 2 Service Manual

Service Manual

Nakamichi

Cossette Deel< 2

CONTENTS
1.	General . .		. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	1
2.	Removal Procedures . . . . . . . . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
	2.	1.	Top Cover Ass'y . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
	2.	2.	Cassette Case Cover Ass'y . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
	2.	3.	Mechanism Ass'y . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
	2.	4.	Front Panel Ass'y . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	3
	2.	5.	Main P.C.B. Ass'y . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
	2.	6.	Power Supply & Logic P.C.B. Ass'y . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
	2.	7.	Control Switch & Display P.C.B. Ass'y . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	4
3.	Test Tapes and Gauges . . . . . . . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
4.	Mechanical Adjustments . . . . . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
	4.	1.	Tape Guide Height Check for Record/Playback Head and Erase Head . . . . . . . . . . . . . . . . . . . . .		5
	4.	2.	Head Base Stroke Check . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	5
	4.	3.	Record/Playback Head Azimuth Alignment and Height Check . . . . . . . . . . . . . . . . ... . . . . . . .		5
	4.	4.	Pressure Adjustment of Pressure Roller . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
	4.	5.	Tape Travelling Check . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
	4.	6.	Eject Damper Adjustment . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
	4.	7.	Reel Motor Speed Adjustment in Play Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .		6
	4.	8.	Tape Speed Adjustment . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
	4.	9.	Lubrication . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	6
5. Parts Location for Electrical Adjustment . . . . . . . . . .				. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	7
6.	Electrical Adjustments . . . . . . . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	8
7.	Mechanism Ass'y and Parts List . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11
	7.	1.	Synthesis . . . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	11
	7.	2.	Front Panel Ass'y (AOl) ..................................................		12
	7.	3.	Front Chassis Ass'y (A02) . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	12
	7.	4.	Chassis Ass'y (A03) ......................................................		13
	7.	5.	Mechanism Ass'y (A04) ...................................................		14
8.	Mounting Diagrams and Parts List . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	15
	8.	1.	Main P.C.B. Ass'y . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	15
	8.	2.	Power Supply & Logic P .C.B. Ass'y . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	17
	8.	3.	Timer Switch P.C.B. Ass'y . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	18
	8.	4.	Headphone P.C.B. Ass'y. . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	18
	8.	5.	Pin Jack P.C.B. Ass'y . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	19
	8.	6.	Shut-off P.C.B. Ass'y .....................................................		19
	8.	7.	Control Switch & Display P.C.B. Ass'y .........................................		19
9.	Schematic Diagrams . . . . . . . . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	20
	9.	1.	IC Block Diagrams . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	20
	9.	2.	Schematic Diagrams . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	23
10.	Wiring Diagram . . . . . . . . . . . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	25
11.	Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	26
	11.	1.	Amplifier Section . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	26
	11.	2.	Mechanism Control Section . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	27
12.	Timing Charts and Eq. Amp. Frequency Response . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	28
	12.	1.	Timing Charts . . . . . . . . . . . . . . . . . . . .	. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	28
	12.	2.	Eq. Amp. Frequency Response ........	, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	29
13.	Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . .			. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .	30

1.GENERAL

1.1.Production No. Production No.: A327

1.2.Destinations

USA, CAN, EP, UK, AUS, SAU, OTR, JPN

Abbreviation		AUS	-	Australia
USA -	U.S.A.	AUS	-	Australia
CAN -	Canada	SAU	-	Saudi Arabia
EP	Europe	OTR -		Other
UK	United Kingdom	JPN	-	Japan

1.3. Parts Supply

(1)Unstocked Parts

Parts' marked with "*"at the head of part No. are not stocked. So, it takes time to supply the parts after we receive your order.

(2)Unsupplied Parts

Parts without part Nos. (indicated as"-" in the parts list) are not supplied.

1.4.CAUTIONS/WARNINGS

(1)	Product Safety Notice	/,\
Parts marked with the symbol		ill in the schematic
diagram have critical characteristics.
Use	ONLY replacement parts	recommended by the

manufacturer.

It is recommended that the unit be operated from a suitable DC supply or batteries during initial check-out procedures.

(2) Leakage Current Check/Resistance Check

Before returning the unit to the customer, make sure you make either (1) a leakage current check or (2) a line to chassis resistance check. If the leakage current exceeds 0.5

1,6. Package Ass'y and Accessory Assty

milliamp, or if the resistance from chassis to either side of the power cord is less than 240 k ohms, the unit is defective.

WARNING - DO NOT return the unit to the customer until the problem is located and corrected.

1.5. Voltage Selector

Voltage selector is installed on the Rear Panel of the Nakamichi Cassette Deck 2 (Other & Saudi Arabia). The voltage selector can select either 110 V/127 V or 220 V/ 240 V at customer's disposal.

Fig. 1

Schematic

Part No,

Description

Q•y

Part No.

Description

Q•Y

Ref. No.

Packaa;e Ass•y

DA04397A

Accessory Ass'Y (USA, CAN)

DA04399A

Accessory Ass'Y (EP)

OF04434A

Packing

DA04406A

Accessory Ass'Y (UK)

OF04456A

Carton Box

DA04398A

Accessory Ass'Y (AUS, SAU, OTR)

DA04396A

Accessory Ass'Y (JPN)

OD06116A

Owner's Manual (English/French/

Germany)

OD06115A

Owner's Manual (Japanese)

DA04388A

Pin-Pin Cord Ass'y

2.REMOVAL PROCEDURES

2.1.Top Cover Ass'Y

Refer to Fig. 2.1.

(1)Loosen screws FOl (2 pcs.) and F02 (4 pcs.), and remove F03 (Top Cover Ass'y),

F02

Fig. 2.1

2.2. Cassette Case Cover Ass'y

Refer to Fig, 2.2.

(1)Press the Eject Knob Ass'y to open F01 (Cassette Case Cover Ass'y).

(2)Pull F01 (Cassette Case Cover Ass'y) upward.

Eject Knob FOi

Cassette

Case

Cover Ass'y

Fig, 2.2

2.3. Mechansim Ass'y

Refer to Fig. 2.3.

(1)Remove the Top Cover Ass'y referring to item 2.1.

(2)Remove the Cassette Case Cover AsSy referring to item 2.2.

(3)Loosen screws FOl (3 pcs,) and F02 (1 pee.).

(4) Dissconnect connectors (CN-4, CN-5, CN-6, CN-14 and CN-15).

(5)Remove F03 (Mechanism Ass'Y) in the direction of the arrow.

Fig. 2.3

2.4. Front Panel Ass'y

Refer to Figs, 2.4.1 and 2.4.2.

(1)Remove the Top Cover Ass'y referring to item 2.1.

(2)Loosen screws F03 (2 pcs,), F02 (1 pee.) and F03 (2 pcs.). See Fig. 2.4.1.

(3)Press claws A (3 pcs.) downward to unhook them.

(4)Disconnect a connector (CN-9) and remove F04 (Front Panel Ass'y), See Fig, 2.4.2.

FOi ~

""--..~~..._.. A

~F02

F03

Fig, 2.4.1

F04

Front Panel Ass'y

Fig. 2.4.2

2.5. Main P.C.B. Ass'Y

Refer to Figs, 2.5.1 and 2.5.2.

(1)Remove the Front Panel Ass'y referring to item 2.4.

(2)Loosen screws FOl (4 pcs.). F02 (1 pee.) and F03 (2 pcs.). See Fig, 2.5.1.

(3)Slide out F04 (Front Chassis Ass'y & Main P.C.B. Ass'y) forward.

(4)Loosen screws F05 (2 pcs.) and FOG (2 pcs,), and remove F07 (Shield Plate), See Fig, 2.5.2.

(5)Loosen screws FOB (2 pcs.) and remove F09 (Main P.C.B. Ass'y),

F03

Fig, 2.5.1

F07

F09

Main P.C.B. Ass'y

Fig, 2.5.2

2.6. Power Supply & Logic P.C.B. Ass'y Refer to Fig. 2.6.

Caution: Unplug the power cord from the AC outlet.

(1)Remove the Top Cover Ass'y referring to item 2.1.

(2)Push FOl (~ower Switch Joint) rearward (in the direction

<Al ).

(3)Plili F01 (Power Switch Joint) ~ntward (in the direction

@) and lift it in the direction (.£)to disengage FOl (Power

Switch Joint) from the Power Switch.

(4)Remove F01 (Power Switch Joint).

(5)Loosen screws F02 (1 pee,), F03 (3 pcs.) and F04 (1 pee.), and remove F05 (Power Supply & Logic P.C.B. Ass'y),

Fig, 2.6

2.7. Control Switch & Display P.C.B. Ass'y Refer to Fig. 2.7,

(1)Remove the Front Panel Ass'y referring to item 2.4.

(2)Loosen screws F01 (2 pcs.) and F02 (2 pcs.), and remove F03 (Shield Plate),

(3)Loosen screws F04 (2 pcs.), unhook claws (6 pcs.), and remove F06 (Control Switch & Display P.C.B. Ass'y).

Fig, 2.7

3.TEST TAPES AND GAUGES

(1)400 Hz Level Tape (DA09005B)

(2)1 kHz Track Alignment Tape (DA09007B)

(3)10 kHz PB Frequency ReSPonse Tape (DA09003B)

(4)15 kHz PB Frequency Response Tape (DA09002B)

(5)20 kHz PB Frequency Response Tape (DA09001B)

(6)15 kHz Azimuth Tape (DA09004B)

(7)3 kHz Speed and Wow/Flutter Tape (DA09006C)

(8)Tape Travelling Cassette (DA09071A)

(9)Reference EXII Tape (DA09111A)

(10)Reference SX Tape (DA09110A)

(11)Reference ZX Tape (DA09109A)

(12)Head Alignment Gauge (DA09092B)

(13)Torque Gauge FWD (DA09082A)

4.MECHANICAL ADJUSTMENTS

4.1.Tape Guide Height Check for Record/Playback Head and Erase Head

With use of a Head Alignment Gauge (DA09092B). 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 Head Ali.gnmeht Gauge (DA09092B), Refer to Fig. 4.1.

(1)Record/Playback Head Tape Guide Height

(a)Load the base of the Head Aligruneht Gauge (DA09092B) carefully and set the cassette deck in Play mode.

(b)Place the small block of the Head Alignment Gauge (DA09092B) on the base.

(c)Slide the small block against the tape guide of the Record/ Playback Head, and check to insure that the block is accepted by the tape guide.

(d)If not, loosen the screw and insert a shim (either 30 µm

(OC80048A), 60 µm (0C80038A), or 100 µm (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 Head Alignment Gauge (DA09092B) carefully and set the cassette deck in Play mode.

(b)Place the small block of the Head Alignment Gauge (DA09092B) on the base,

(c)Slide the small block against the tape guide of the Erase Head, and check whether the block is accepted by the tape guide.

4.2.Head Base Stroke Check

Refer to Fig. 4.2.

(1)Load the base of the Head Alignment Gauge (DA09092B) 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 Head Alignment Gauge (DA09092B) on the base.

(4)Contact the small block with the Record/Playback Head surface and the Erase Head surface, and check whether the end of the small block is located within the specified tolerance as shown in Fig, 4.2.

4.3.Record/Playback Head Azimuth Alignment and Height Check

Refer to Fig, 4.1.

(1)Contact an AC voltmeter to the Output Jacks,

(2)Load a 16 kHz Azimuth Tape (DA09004B) and set the cassette deck in Play mode.

(3)Tum the Azimuth Alignment Screw until the outputs of both channels become maximum.

(4)Load a 1 kHz Track Alignment Tape (DA09007B) and set the cassette deck in Play mode,

(6)Check to insure that the readings of both channels on the AC voltmeter are below -26 dB.

If not, replacement of the Record/Playback Head will be required.

(6)Apply a quantity of lock tight paint to the Azimuth Alignment Screw.

Azimuth Alignment Screw

Fig. 4.1

Gauge

Fig. 4.2

4.4. Pressure Adjustment of Pressure Roller Refer to Fig, 4. 3.

(1)In Play mode, measure the Pressure of the Pressure Roller against the capstan and check whether the pressure is in a range of 360 ±40 g,

(2)If pressure is out of the range, correct it by changing the installation point of the Pressure Roller Spring.

Fig. 4.3

4.5, Tape Travelling Check

Load a Tape Travelling Cassette (DA09071A) and set the cassette deck in Play mode to check the followings:

(1)After more than 2 seconds, the fluctuation of the tape travelling on the Record/Playback Head is small.

(2)Tape is in contact with the head sufficiently,

(3)Tape waving is small on the heads and pressure roller,

Fig, 4.4

4.6. Eject Damper Adjustment

Refer to Fig. 4.5. 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 action by the Damper Adjustment Screw.

CCW: Damper moves fast. CW: Damper moves slowly,

.n_Oe<:reose

Iocc«>"'

Damper Adjustment

Screw

Eject Damper

Fig. 4,5

4, 7, Reel Motor Speed Adjustment in Play Mode

(1)Load a Torque Gauge FWD (DA09082A) and set the cassette deck in Play mode.

(2)After 5 to 10 seconds, adjust VR501 on the Power Supply & Logic P.C.B. Ass'y to obtain exactly 45 g-cm on the torque gauge,

(3)Check that the back tension is in a range of 1.5 to 5 g-cm.

4.8. Tape Speed Adjustment Refer to Fig. 4.6.

(1)Connect a frequency counter to the Output Jacks.

(2)Load a 3 kHz Speed and Wow/Flutter Tape (DA09006C) 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.

Decrease~

Increose

Fig, 4.6

4.9, 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 (EP-56) Reel Hub Shaft

( 4) Anderol 456 Capstan Shaft

Note: we suggest that you use the above specified lubricant or equivalent type,

The company· dealing in the above lubricant is as follows:

(a)Molykote @ Grease (X5-6020)

Dowcoming Co., Ltd., 1-15-1 Nishishinbashi, Minatoku, 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., g..3.5 Hatchobori, Chuoku, Tokyo, Japan

5. PARTS LOCATION FOR ELECTRICAL ADJUSTMENTS

Power Supply a Logic P.C. B.

Main P.C.B.

------- Rec . Col.

•

~~~

VRIO,L VRf04L VR103L

VRl05R VRl04R VRl03R

l!I

l!I l!I

VRl02L

0l!I

Ploybock Level !400Hzl

YR~! IQ!

@'IJMP> "'"'

Reel Motor Speed~

CP!oy)

PloybockLevel (20KHz)

VRlllR

VRl11L

VLIOOR

VR!06r.rirl

Erase Current~

Fig, 5

6.ELECTRICAL ADJUSTMENTS

S'Il!P

Il:Ell

SIGRAL

OllTPDT

MODE

AD.JUST-

Rl!IWIKS

SOURCE

COllHl!CrIOll

MEHT

Preliminary

Balance -

Set the Cassette Deck

2 as shown in MODE.

Step

Center

Bias Tune -

Center

Tape

Type

MPX Filter

- OFF

Dolby NR

- OFF

Reel Motor

Torque

Playback

Power

1. Play back a Torque Gauge FWD and adjust

Speed

Gauge FWD

Supply

VR501 to obtain 45

g-cm on the torque

Adjustment

(DA09082A)

gauge.

(Play)

Logic

2. Check that the deviation of the torque

P.C.B.

value is within ±5

g-cm of the center

VR501

value.

Tape Speed

3 kHz

Frequency

Playback

Tape

Adjust the volume incorporated in the

Adjustment

Speed

Counter to

Tape

Speed

capstan motor

to obtain 3 kHz ±15 Hz on

and \low/

Output

Type

Adj.

the frequency

counter.

Flutter

Jacks

Volume

Tape

(Capstan

(DA09006C)

Motor)

Meter Level

400 Hz to

AC Volt-

Record.Pause

Main

1. Feed in 400 Hz and adjust the Rec

Calibration

Input

meter to

P.C.B.

Level control to obtain 500 mV -0.5

Jacks

Output

VR112L

dB on the AC voltmeter.

Jacks

VR112R

2. Adjust VR112L (VR112R) so that the 0

dB segment of the level meter starts

illuminating.

MPX Filter

19 kHz

AC Volt-

Record,Pause

Main

1. Adjust the Rec Level control to obtain

Adjustment

:tlOO Hz

meter to

MPX -

OFF/ON

P.C.B.

500 mV (O

dB) on the AC voltmeter.

to Input

Output

VL!OOL

2. Set the MPX Filter switch to ON and

Jacks

VLlOOR

adjust VLlOOL (VLlOOR) to obtain minimum

reading on the AC voltmeter (minimum

reading will be less than -30 dB).

Record/

15 kHz

AC Volt-

Playback

Record/

Adjust the Record/Playback Head Azimuth

Playback

Azimuth

meter to

Dolby NR -

Playback

Alignment Screw to obtain maximum

Head

Tape

Output

OFF

Head

readings for both channels on the AC

Azimuth

(DA09004B)

Jacks

MPX -

OFF

Azimuth

voltmeter.

Alignment

Tape

Align-

Type

ment

Screw

Playback

400 Hz

AC Volt-

Same

Main

Adjust VR102L (VR102R) to obtain 500 mV on

Level

Level Tape

meter to

above

P.C,B.

the AC voltmeter.

Calibration

(DA09005B)

Output

VR102L

Jacks

VR102R

STEP

l'IJ!K

SIGHAL

OUTPUT

K>DE

ADJUST-

SOURCE

COllllJ!CTION

MENT

Playback

400 Hz

AC Volt-

Playback

Main

1. Load a 400 Hz level tape.• play it

Frequency

Level

Tape

meter to

Dolby NR

P.C.B.

back. and read the playback level.

Response

(DA09005B)

Output

OFF

VRlllL

Load 10 kHz,

kHz and 20 kHz PB

Adjustment

10 kHz

Jacks

MPX - OFF

VRlllR

frequency response tapes and play

Frequency

Tape

them back.

Adjust the

record/play-

Response

Type IV

back head azimuth to obtain maximum

Tape

readings for both channels on the

(DA09003B)

AC voltmeter with each tape.

15 kHz

Check that the playback levels are

Frequency

as follows with respect to the level

Response

for 400 Hz level tape.

Tape

10 kHz: -20 dB -2 to +2 dB

(DA09002B)

15 kHz: -20 dB

-2 to +3 dB

20 kHz

20 kHz: -20 dB -2 to +4 dB

Frequency

If the level at 20 kHz is out of the

Response

range, adjust VRlllL (VRlllR) to obtain

Tape

satisfactory results.

VRlllL (VRlllR)

(DA09001B)

compensates

the

playback frequency

response at 20 kHz as shown below:

l_A=rApprox. 5d8

IOK

20K

3. Conduct step 6 11 Record/Playback Head

Azimuth Alignment".

Bias

None

Frequency

Record,Pause

Main

1. Connect an additional 0.1 ohm resistor

Oscillation

Counter

Tape

P.C.B.

in series to

the

Erase Head and

Frequency

between

Type

VT!OO

connect the AC voltmeter across it.

and Erase

terminals

Dolby NR

JS!OO

2. Adjust VTIOO to obtain 105 kHz ±1 kHz

Current

and 2

OFF

VR106

on the

frequency

counter.

Adjustment

of CN15

MPX -

OFF

If bias oscillation frequency is above

Main P.C.B.

106 kHz, short-circuit

JSlOO with a

and

jumper wire as shown left and re-adjust

AC Volt-

VTlOO

again.

meter

Adjust

VR106

to obtain 20 mV (200 mA)

across

the

on the

AC voltmeter.

additional

4. After completion of the erase current

0.1 ohm

adjustment, re-check the bias

resistor

oscillation

frequency.

Remove

the

additional 0.1 ohm resistor.

[Serial No. =A32705801)

Serial

Nos.:

[ A32701001-05800

JS100 ~or~JS100

8JS100

CD®

f I> 12

Bias Trap

None

Volt-

Same as

Main

Adjust VL102L

(VL102R) to

obtain minimum

Adjustment

(remove

meter

above

P.C.B.

reading on the

AC voltmeter.

(Record

input

between

VL102L

Amp.)

signals)

pins

VL102R

(Leh)

and

(GND)

(Reh)

and

(GND)

of TPIOO

on Main

P.C.B.

Nakamichi Cossette Deck- 2 Service Manual

STEP	IlEH	SIGl!IAL
		SOUllCl!

11	Record	400	Hz
	Level	(O	dB)
	Calibration	and
	and	18	kHz
	Recording	(-20 dB)
	Bias	to	Input
	Current	Jacks
	Adjustment

OUTPUT llODI!

COllHl!CTIOH

AC Volt-		Record	and
meter	and	Playback
Distortion		Tape -
Meter	to	Type	IV/II/
Output			I
Jacks		Dolby NR -
			OFF/C
		MPX -	OFF

AD.JUST-

MENT

Main

P,C,B,

(Level) Type IV VR105L VR105R Type II VR104L VR104R

Type I

VR103L

VR103R

(Bias)

Type IV VR109L VR109R Type II VR108L VR108R

Type I

VR107L

VR107R

Adjustment should be made in the order of zx. SX and EX tapes.

1.Set the cassette deck in Record/Pause mode.

2.Feed in 400 Hz and adjust the Rec Level control to obtain 500 mV (O dB) on the AC voltmeter.

3.Load a reference ZX tape. reference SX tape and reference EXII tape.

4.Set the Dolby NR switch to OFF.

5.Feed in 400 Hz (0 dB) and record, rewind. and play it back.

Adjust VR105L (VR105R) for ZX tape• VR104L (VR104R) for SX tape and VR103L (VR103R) for EXII tape so that the

played back output levels are 500 mV (0 dB) on the Ac voltmeter.

6.Set the Dolby NR switch to c.

7.Feed in 18 kHz (-20 dB) and record,

rewind, and play it back.

Adjust VR109L (VR109R) for ZX tape, VR108L (VR108R) for SX tape and VR107L (VR107R) for EXII tape so that the

played back output	levels are 50 mV
(-20 dB) on the AC	voltmeter.

8.Repeat above 4 to 8 two or three times.

9.Set the Dolby NR switch to OFF.

10.Feed in 400 Hz (O dB) and record, rewind, and play it back. Check to insure that the total harmonic distortion is less than 1.2% for ZX

and EXII tapes and 1.6% for SX tape. If the total harmonic distortion exceeds the specified value, re-adjust VRlllL (VRlllR) in Step 8 "Playback Frequency Response Adjustment11 , and repeat above steps till satisfactory results are obtained.

7.MECHANISM ASS'Y AND PARTS LIST

7.1.Synthesis

Me¢hOnism A.Sy

09(A041

L12

06 IA02J

L05

		~LOS
	~,.	-~~5
	~,.	~,14
		~,14
		L04
	02
		L04
		Fig, 7.1

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