Nakamichi 600 II Service Manual

~	Service Manual

Nakamichi

Nakamichi

60011

2 Head Cassette Console

1.General

2.Principle of Operation

2.1. 2-Head Configuration

	2. 2. Playback Eq. Amp. Circuit
	2. 3. Test Tone Circuit
	2.	4.	Bias Osc. Circuit
	2.	5.	Unattended Record or Playback, and Shut-off Circuit ...
		2.5.1.		Unattended Record or Playback .
		2.5.2. Shut-off Circuit
3.	Removal Procedures					13
	3.	1.	Cassette Lid Plate			13
	3.	2.	Cabinet			13
	3.	3.	Volume Cap			13
	3.	4.	Handle Ass'y			13
	3.	5.	Front Panel Ass'y			13
	3.	6.	Mechanism Ass'y			13
	3.	7.	Front Control Ass'y			13
	3.	8.	Volume P.C.B. Ass'y			13
	3.	9.	Record/Playback Head Ass'y, Erase Head and Pressure Roller Ass'y .			14
	3. 10.		Cassette Case Ass'y			14
	3. 11.		Cassette Lid Ass'y			14
	3. 12.		Control Button Ass'y ................. .			14
	3. 13.		Counter Holder Ass'y ............ .			15
	3. 14.		Reel Hub Ass'y {Supply, Take-up)			15
	3. 15.		Shield Cover, Motor and Motor Governor .			15
	3. 16.		Flywheel Ass'y		.................. .	16
	3. 17.		Idler Pulley Ass'y		............... .	16
	3. 18.		Main P.C.B. Ass'y ............ .			16
	3. 19.		Dolby NR P.C.B. Ass'y			16
	3. 20.		Meter Ass'y		.............. .	16
	3. 21.		Power Switch Ass'y			16
	3. 22.		Record Link Ass'y .			16
	3. 23.		Rear Panel Ass'y			16
	3. 24.		Power Supply P.C.8. Ass'y			16
	3. 25.		Headphone Jack			16
4.	Measurement and Maintenance Instrument					17
	4.	1.	Measurementlnstrument			18
	4.	2.	Maintenance Instrument ..			18
5.	Mechanical Adjustments					18
	5.	1.	Take-up Torque and Rewind Torque Adjustment			18
	5.	2.	Tape Speed Adjustment			18
	5.	3.	Headblock Adjustment			19
		5.3.1.		Adjustment of Tape Guide Height (Erase, Record/Playback)		19
		5.3.2.		Record/Playback Head Height Adjustment and Azimuth Alignment		19
	5.	4.	Head Base Stroke Adjustment ..			19
	5.	5.	Pause Timing Adjustment			20
	5.	6.	Belt Travelling Adjustment			20
	5.	7.	Flywheel Adjustment			20
	5.	8.	Brake Timing Adjustment .			20
	5.	9.	Mute Switch and Start Switch Adjustment			21
	5. 10.		Solenoid Position Adjustment			22
	5. 11.		Record Link Adjustment			22
	5.	12.	Lubrication			22
	5.	13.	Tape Travelling Adjustment			23
6.	Electrical Adjustments and Measurements					24
	6.	1.	Adjustment and Measurement Instructions .			24

	6.	2.	Frequency Response Adjustment				27
		6.2.1.		Playback Frequency Response Adjustment			27
		6.2.2.		Record Current Frequency Response Adjustment			27
7.	Parts Location for Electrical Adjustment						28
8.	Mounting Diagram and Parts List						28
	8.	1.	Dolby NR P.C.B. Ass'y				28
	8.	2.	Main P.C.B. Ass'y				29
	8.	3.	Cal. A P.C.B. Ass'y				31
	8.	4.	Cal. B P.C.B. Ass'y				31
	8.	5.	Switch P.C.B. Ass'y .				32
	8.	6.	VR P.C.B. Ass'y				32
	8.	7.	Meter P.C.B. Ass'y				33
	8.	8.	DIN Pin Jack P.C.B. Ass'y .............. .				33
	8.	9.	Power Supply P.C.B. Ass'y				34
	8.	10.	Shut-off P.C.B. Ass'y				35
	8. 11.		MHX Governor B				35
9.	Mechanism Ass'y and Parts List						37
	9.	1.	Synthesis (A01)				37
	9.	2.	Chassis Ass'y				38
		9.2.1.		ChassisAss'y (1/2) (A02·1)			38
		9.2.2.		Chassis Ass'y (2/2) (A02-2)	............. .		39
	9.	3.	600!1 Mechanism Ass'y (A03)				41
	9.	4.	Front Control Ass'y {A04)				43
	9.	5.	Record Link Ass'y {A05)				43
	9.	6.	Push Button Ass'y iA06)				43
	9.	7.	Rear Panel Ass'y (A07) ..				45
	9.	8.	Power Transformer Ass'y {AOB)				45
	9.	9.	Power Switch Ass'y (A09)				45
	9. 10.		Meter Ass'y (A 10)				45
	9.	11.	Mechanism Ass'y			. . . . . . .	47
		9.11.1.		Mechanism Ass'y {1/2) (801-1)		. . . . . . . . . . . . .	47
		9.11.2.		Mechanism Ass'y (2/2) (801-2)			49
	9. 12.		Cassette Case Ass'y (802) ..				51
	9. 13.		Head Base B Ass'y (803)				51
	9. 14.		Counter Holder Ass'y (804)				51
	9. 15.		Flywheel Holder C Ass'y (805) .				51
	9. 16. MHX Motor Ass'y B (806)					......	51
	9. 17.		Record/Playback Head Ass'y {807)				52
10.	Wiring Diagram						53
11.	Eq. Amp. Frequency Response						54
	11.	1.	Playback Frequency Response				54
	11.	2.	Record Current Frequency Response				54
12.	Block Diagram						54
13.	Schematic Diagram						55
	13.	1.	Amplifier				55
	13.	2.	Mechanism				56
14.	Troubleshooting ....						58
	14.	1.	Note				58
	14.	2.	Troubleshooting				58
	14.	3.	Check Method When Parts are Replaced				60
15.	Specifications						62

1. GENERAL

Nakamichi 600! I control functions are shown with reference to the following explanations.

To maintain the optimum performance of Nakarnichi 600!!, maintenance such as cleaning of head, capstan shaft and pressure roller, and demagnetization of heads, lubrication, etc. are required.

	Fig.1.1	FrontView(Black)
	Cassette Lid	17.	Power Switch
2.	Record Button	18.	Dolby NR Switch
3.	Rewind Button	19.	MPXSwitch
4.	Stop/Eject Button	20.	Test Tone Switch
5.	Playback Button	21.	Test Tone Frequency Switch
6.	Fast Forward Button	22.	Eq. Switch
7.	Pause Button	23.	Tape Switch
8.	Bias Adjustment Controls	24.	Tape Start Memory Switch
9.	Bias Calibration Controls	25.	Tape Counter Reset Button
10.	Output Level Control	26.	Tape Counter
11.	Record Level Controls	27.	Line Input Jacks
12.	Master Input Level Control	28.	DIN Socket
13.	Headphone Jack	29.	Line Output Jacks
14.	Record Calibration Controls	30.	AC Line Cord
15.	Lamps	31.	Speed Calibration Adjustment
16.	Peak Level Meters

Fig. 1.2 Rear View

	Fig. 1.3 Front View (Silver)
Notes: 1.	When cassette lid is opened, no control button operates.
2.	With record mode and tone switch ON, 400 Hz or 10 kHz test tone oscillates by the selection of test tone
	frequency switch 400 Hz or 10 kHz.
3.	When mechanism ass'y is reassembled, check to insure whether the record link ass'y (see Fig. 3.12) is fixed to
	the correct position, i.e. when record button is depressed (cassette is loaded). record link acts.

4.When memory counter is in a range of "000" to "010", memory rewind stop function {stops at "999") does not operate because of less rewind time until "999" the electric charge for the capacitor which will conduct to drive the solenoid to shut-off is insufficient.

2.PRINCIPLE OF OPERATION

2.1.2·Head Configuration

Despite the fact that the N-60011 is of 2-head cassette tape deck, it will provide you with performance up to 20 kHz. To arrive at such performance, the N-60011 now incorporates 2 great improvements.

One of them is further improvement of record/playback head and the other being the improvement of headblock, in other words, narrower gap of the record/playback head increased the playback frequency response at highs, and modification of the headblock has resulted in more stabilized tape travel.

Accuracy of tape travel is one of the most essential factors for a device to optimize its performance. Inaccurate tape travel will therefore induce deterioration exemplified by the following:

vibration will be given to tape travel, as a result of which flutter and modulation noise will become increased

b.insufficient tape-to-head contact will result in level drops

c.tape skew will become greater and frequency re-

sponse will become decreased

Needless to say, constant tape travel must consist of smooth drive mechanism, as well as of the fact that tape,

)='1/f•TapeSpee4/20

GapWidt0=0.9/l.5um

Fig. 2.1.1 Equivalent Gap Width

/

:--+--+-+-+-+--

'-3 -2 -I D +I +2 +J' +4' H'

heads and tape guide are placed in the most appropriate positions. The following describes the details of the 2 different improvements newly incorporated in the

N-600!1:

(1) SuperHead

Even if an Azimuth misalignment is noted because of tape skew, deterioration of performance has been greatly reduced upon decreasing the gap of the Record/Playback Head from 1.5 microns to 0.9 micron.

Where gap width is decided to be d, lt is pubIicly known that the gap loss Ld is obtained by the following formula:

. ad

Ld = 20 log sin rrY (dB)

T

Legend: d "' Gap width of Playback head

A"' Recording wave length (A==v/f, V"'Tape speed)

The SuperHead employs a narrower gap than the conventional heads, which resulted in decreasing loss against frequencies at highs and an improvement of frequency response.

Where there should be any azimuth misalignment, it would equivalently converted to gap loss and will give affect to frequency response. Fig. 2.1.1 shows Equivalent Gap Width, Fig. 2.1.2 azimuth misalignment at frequency of 20 kHz vs azimuth loss (playback output loss) when gap width is considered to be a parameter, and Fig. 2.1.3 shows frequency vs azimuth loss when azimuth misalignment is considered to be a parameter.

Fig. 2.1.2 Azimuth Misalignment vs Azimuth Loss	Fig. 2.1.3 Frequency vs Azimuth Loss
{Playback Output Loss) at 20 kHz

(2)

Headblock

b. Adjustment

for Record/Playback Head Height and

Although the N-60011 is

of 2-head cassette system, the

Azimuth:

entire head adjustment functions are incorporated in the

The Record/Playback

Head is fitted to a steel plate

head

plate assembly as can be noted with the 3-head

spring from head plate ass'y, and its height is adjusted

cassette systems produced by Nakamichl Research Inc.,

with a head height adjustment screw.

and

each of the adjustments can be performed indivi-

While adjusting Record/Playback Head, Azimuth will

dually without giving effect to another adjustment. See

change when height is adjusted, whereas height will

Fig. 2.1.4.

change when azimuth

is adjusted, as a result of which

a.

Adjustment of Tape Guide Height:

adjustment of both height and azimuth will have to

One side of the erase head is firmly fixed, whereas the

be repeated.

other side can be adjusted with an adjustment screw.

Incorporated in the N-60011 therefore is a function

The adjustment screw is placed on a spring, and

with which azimuth can stay stabilized even though

therefore either tightening or loosening it will make it

the head height is adjusted.

possible to adjust the height of the tape guide. The

Figs. 2. l.5 and 2.1.6 show the representative azimuth

tape guide of the record/playback head consists of a

changes when head

height is adjusted, and changes of

part of the head plate and can be adjusted separately

height when

azimuth

is adjusted together with the

from the record/playback head. Adjustment is con-

pertinent formulas.

ducted by means of a Tape Guide Adjuster B Jig

(0009011 Al.

R/PHEAD

R/PHEAD AZIMUTHAUGNMENT

HEIGrADJ.

:

•@

Fig. 2.1.5

Azimuth Changes

l:.ah =

acos{B-l:.8)-acosB

asinB·l:.B

l:.bh =

bsin8 "; bAB

(lfl:.8 is very small}

Ah

t:..ah +Abh

Fig. 2.1.4

Head Housing

(asin8 + b) l:.B

ADJ.

•@

~

A@

Ah .

Fig. 2.1.6

Height Changes

(asint:..O + bcost:..8)-b

asinAB + b{cos8-1)

{If AB

is very small; sinAB=: t:i.8, cost:..e=: 1)

t:i.h=afi.B

2.2 Playback Eq. Amp. Circuit

Fig. 2.2.1 shows the playback equalizer circuit, and Fig. 2.2.2 is its system diagram. Fig. 2.2.3 shows the time constant of equalizer. The playback head is connected with circuit's input.

Amplifier 1 (0101 and 0102) is an equalizer amplifier and its time constant is illustrated in Fig. 2.2.3.

R,L,C1 and C2 compose of a peaking circuit. This circuit compensates the air gap loss of the playback head so that high"frequency response may be improved.

Phase shifter acts to compensate the phase delay charac· teristics of the frequency response. Phase delay characteri· sties are improved within 30 degrees up to 10 kHz. Therefore modulation for the complex wave will reduce. Playback Eq. Amp. gain is adjusted by semi·fixed volume VR101 {Amp. 2-0104, 105) to obtain 580 mV output level when 400 Hz Level Tape (DA09005A) is being played back.

Equalizer switch (70 µs/120 µs) is connected with Amp 2. The overall time constants in Playback Eq. Amp. are as follows:

Eq. SW70µs

3180µs (50 Hz)+ 70µs (2274 Hz) Eq. SW-120µs

3180µs (50 Hz)+ 120µs (1326 Hz)

Shown below is the table for the position of tape switch and Eq. switch:

Tape SW Eq.SW

SX 70µs

EX 120µs

EX 70µs

Tape

Nakamichi SX, TDK SA Maxell UOXL"!I

Scotch Master 70 µs

Low·Noise High-Density (including EX, EXll TDK AD, Maxell UDXL-1 Scotch Master 120 µs)

Nakamichi EX, EXI I

When 70 µs is selected at EX tape position, signal to noise ratio will be improved by 4.7 dB (WTO).

Fig. 2.2.3 Playback Eq. Amp. Time Constant

Eq~t2*-.0;;s

070.U•

Fig. 2.2. 1 Playback Eq. Amp. Circuit

Rl20(R220)

Input

70jJ;rf 120jJS

lEg.Switch

Fig. 2.2.2 Playback Eq. Amp. System Diagram

2.3. Test Tone Circuit

By means of the Ope-Amp. IC, the N-60011 oscillates 2 kinds of tones, that are 400 Hz (0 dB} for record level calibration and 10 kHz (-8 dB) for bias calibration.

As shown in Fig. 2.3.1, the Test Tone consists of oscillation portion through !C4558 and band pass filter comprising either of 400 Hz or 10 kHz, and either of 400 Hz or 10 kHz can be selected by the Test Tone Frequency Switch. Power will be supplied to the Test Tone Circuit in Record mode and will be made only while the Test Tone Switch is set to ON.

The circuit also contains a lamp circuit preventing erroneous adjustment as may occur while in bias calibration or record level calibration, and each of the said \amps will be lit as follows depending upon the conditions of the Test Tone Frequency Switch and Tape Switch:

S1: Test Tone Frequency Switch (400 Hz/10 kHz) S2: Tape Switch (EX/SX)

S1 (400 Hz). S2 (EX) - Rec. Cal. EX Lamp ON S1 (400 Hz). S2 {SX) - Rec. Ca!. SX Lamp ON S1 (10 kHz). $2 (EX) - Bias Adj. EX Lamp ON S1 (10 kHz). S2 (SX) - Bias Adj. SX Lamp ON

IC301-1/2 consists of oscillation function, feeds its output back to input and oscillated square wave up to power source voltage level so that the oscillation voltage can be stabilized. A capacitor is connected to No. 6 terminal of the IC301-1/2 for the convenience while changing over one frequency to another. (400 Hz: 0.0178 µF, 10 kHz: 620pF)

Band pass filter is created between lC301-1/2 and 2/2, and the sine wave of the selected frequency will be obtained at the output terminal 1 of the 2/2.

With regard to band pass filter curve, please refer to Fig. 2.3.2

~*A~

'"'"' r-

3DKHi

Fig. 2.3.2

Power will be supplied to each of the Lamps through the Tape Switch, and the Lamps are connected to GND by way of the Test Tone Frequency Switch and Inverter 0305 activated by the said Switch.

Fig. 2.3.1 Test Tone Circuit

2.4 Bias Osc. Circuit

Fig. 2.4, shows a push-pull oscillator with an oscillation frequency of 105 kHz which is constructed by capacitors C302 and C303 decoupling the collectors and bases of two tansistors (0301 and 0302).

This is used to provide recording bias and as an erase signal. By depressing the record button, the bias oscillator power supply is activated and oscillation begins. When the record mode is released, oscillator output is damped by the discharge of C304. This prevents magnetization of the head.

In the conventional oscillation circuit, the bias adjustment for SX and EX has been conducted only at the output side of the Bias Osc., which is also applied to N-60011 but plus variation of the voltage to be fed to the oscillation

circuit. In normal adjustments, the Bias Adjustment Controls fitted with a center lock is first set to center (100 ohms) and is managed to correspond to each of the tape with a bias calibration semi-fixed volume. Under such state, setting the control with center lock to 0 - 200 ohms will vary the voltage to be applied to the Bais Osc., thereby bias control is carried out.

Where another different tape is used, bias current can be varied approximately by ± 10%, which can therefore be applied to a certain variety of differnt tapes through only the adjustment of the Bias Adjustment Control (there would be approximately ± 2 dB difference of level between maximum and minimum at 20 kHz against center

(OdB)).

Fig. 2.4 Bias Osc. Circuit

2.5.Unattended Record or Playback, and Shut-off Circu it

2.5.1.Unattended Record or Playback

{1) Depress the record button then depress the play button (depress only the play button for unattended playback).

(2)Depress the pause button.

{3) Turn OFF the external power source.

(4)When external power turns ON, approximately 4 seconds later, the transport will automatically release itself from the pause mode and begin to record (or play).

2.5.2. Shut-off Circuit

Fig. 2.5.2 and 2.5.3 show the shut·off circuit and timing chart. Fig. 2.5.1 shows the flow chart for the shut-off function.

Following are explanations according to the order of the flowchart Nos.:

Playback,Recocd

FF,REW

_fl_

Fig. 2.5.1 Shut·off Flow Chart

10

(1)External Power ON

When external power is turned ON at attended record or playback mode, transistor 0606 turns to ON approximately 4 seconds later. By the 0606 ON, differentiated positive pulse is added to the 0602 base through capacitor C607.

Then 0602 turns to ON and 0601 base current flows. 0601 turns to ON and base current of the 0602 is supplied through 0601.

Namely 0602 and 0601 construct a memory circuit and triggered by a pulse applied to 0602 base.

When 0601 turns to ON solenoid is driven by the discharge of C606 (2200µF).

As the resistance of the solenoid is about 12-ohrn, C606 is discharged quickly, though C606 is charged through resistor R615 (470-ohrn).

About 70 rnsec after, the voltage of 0601 collector becomes less than about 1.2 V, then enough base current does not flow to the 0602, and 0602 turns to OFF subsequently 0601 turns to OFF.

C606 starts charging again preparing for the next solenoid drive.

From the above, solenoid works as a pulse motion and driven solenoid performs shut·off and releases the pause button.

(2)Tape End

Counter pulley linked to a take-up reel turns and switches a Hall IC ON/OFF repeatedly.

At a tape end, pulley stops and the Hall IC ON/OFF operation stops. Therefore the discharge of the C604 through 0604 (synchronizing with the periodic Hall JC ON/OFF) stops. Then C604 starts charging, and when the voltage across C604 exceeds about 4.5 V, 0603 turns to ON and 0601 turns to ON.

The principle how to drive the solenoid is the same as preceding item (1).

Solenoid acts to release the play, record, FF and REW buttons.

Therefore start switch opens and no power supply(+ 18 V) is applied to the shut-off P.C.B. ass'y and motor.

Note: In the Models bearing serial Nos. A206.7 05000 and smaller, a reed switch is incorporated instead of a Hall IC. One magnet is mounted in the counter pulley and 2 pulses are generated for one rotation.

Ha!I IC operates on alternative magnetic fields. 4 pulses are generated for one counter pulley ratation. Hall IC provides the following improvements;

a.Quick response of shut-off.

b.No mechanical noise from IC, as the Hall IC has no moving elements.

(3)Stop Button Depressing

When stop button is depressed play, record, FF and REW buttons are released mechanically.

(4)Power OFF

DC power supply {+ 18 V) will discharge by the power switch OFF.

Since the discharge time constant of the C606 is great, the voltage of the 0605 base (i.e. + 18 V) becomes low with respect to the emitter.

Therefore 0605 turns to ON, 0603 turns to ON and then 0601 turns to ON. Solenoid is driven and control buttons are released.

In case pause button is depressed, solenoid does not work because 0603 base is connected to ground through pause button, and no control button is released. Thus unattended record or playback is possible.

(5)Memory Rewind

When the tape counter reaches "999" counter switch closes. At memory switch ON in rewind mode, the differentiated negative trigger pulse is added to the 0601 base and 0601 turns to ON. And solenoid is driven.

11

;::::::,~

{Play).

"'"'"""'°"~

StortSW ""'"'""3~

,.,:,::,::::i'" Q601Coll•otorQ603Bo<e

Q601Collo<tor	Soleoold	""L
Solenold

Fig. 2.5.3 Shut-off r imingChart.

12

3.REMOVAL PROCEDURES

3.1.Cassette Lid Plate

Refer to Fig. 3.1. Depress the eject button to open cassette case ass'y, then remove F01 (cassette lid plate}.

3.2. Cabinet

Refer to Fig. 3.2. Remove F01 (5 places) and F02

(cabinet).

3.3. Volume Cap

Refer to Fig. 3.2. Remove F03 through F05.

3.4. Handle Ass'y

Refer to Fig. 3.2. Remove F06 (4 places) and F07 {handle ass'y}.

3.5. Front Panel Ass'y

Refer to Fig. 3.2. Remove FOB (front panel ass'y).

3.6. Mechanism Ass'y

Refer to Fig. 3.3. Remove front panel ass'y referring to above items 3.1 through 3.5. Remove F01 through F03 and F04 (mechanism ass'y}.

3.7. Front Control Ass'y

Refer to Fig. 3.3. Remove front panel ass'y referring to item 3.5. Remove F05 and F06 (front control ass'y).

3.8. Volume P.C.B. Ass'y		Fig. 3.2
Refer to Fig.3.3.	Remove front panel	ass'y referring to
item 3.5. Remove	F07 through F09 (volume P.C.B. ass'y).

FI

Fig. 3.1

Fig. 3.3

13

3.9.Record/Playback Head Ass'y, Erase Head and Pressure Roller Ass'y

Refer to Fig. 3.4. Remove hont panel ass'y referring to item 3.5.

(1) Pressure Roller Ass'y

Remove FOt then pressure roller ass'y. {2) Record/Playback Head Ass'y

Remove F02 through F04 then record/playback head ass'y,

(3) Erase Head

Remove F05 through FOB then erase head.

Note: When record/playback head is replaced, twist signal wires (red and white) which are soldered to head terminals for reducing the interference of hum.

3.10. Cassette Case Ass'v

Refer to Fig. 3.5. Remove mechanism ass'y referring to item 3.6. Remove FOt through F07.

Note: Remove F04 and F05 by pincers with care.

3.11. Cassette lid Ass'y

Refer to Fig. 3.5. Remove cassette case ass'y referring to item 3.10. Remove FOB through F12.

Fig. 3.4

3.12. Control Button Ass'y

Refer to Fig. 3.6. Remove mechanism ass'y referring to item 3.6. Remove F01 through F05, then control button ass'y.

Note: Following are assembled in pair.

F06·F07, F08-F09, F10-F11, F13-F14, F15-F16

Fig. 3.5

Fig. 3.6

14

3.13. Counter Holder Ass'y

(1) Hall IC System

Refer to Fig. 3.7. Remove front panel ass'y referring to item 3.5. Remove F01 through F04, then counter ass'y, memory switch and ha!! IC P.C.B. ass'y.

(2) Reed Switch System

Refer to Fig. 3.8. Remove front panel ass'y referring to item 3.5. Remove F01 through FOB, then counter ass'y, memory switch and reed switch.

Note: The leads of reed switch shall not be in contact with the chassis.

Fig. 3.7 Serial No. A206.7 05001 and greater

Fig. 3.8 Up to serial No. A206.7 05000

3.14. Reel HubAss'y (Supply, Take-up)

Refer to Fig. 3.9. Remove Cassette case ass'y referring to item 3.10. Remove F01 and F02, then supply and take-up reel hub assemblies.

3.15. Shield Cover, Motor and Motor Governor

Refer to Fig. 3.10. Remove mechanism ass'y referring to item 3.6. Remove F01 through F03 (shield cover) and F04 through F06 (motor governor}. Dismount F07 and F08, and lift motor, and then remove F09 and F10. Loosen F11 and remove F12 and motor.

Note; Readjustment of belt travelling, tape speed and wow/flutter will be required.

Fig. 3.9

Fig. 3.10

15

3.16. Flywheel Ass'y

Refer to Fig. 3.11. Remove mechanism ass'y referring to item 3.6. Remove F01 through F05, F06 {flywheel ass'y} and F07.

Note: Readjust the clearance between flywheel and flywheel holder. Check on belt travelling, tape speed and wow/flutter will be required.

3.17. Idler Pulley Ass'y

Refer to Fig. 3.11. Remove flywheel ass'y referring to item 3.16. Remove FOB and F09 (idler pulley ass'y). Note: Readjust the brake timing. Check on belt travel-

ling, tape speed and wow/flutter will be required.

3.18. Main P.C.B. Ass'y

Refer to Fig. 3.12. Remove front control ass'y referring to item 3.7. Remove F01 through F04, then F05 (main P.C.B. ass'y).

3.19. Dolby NA P.C.B. Ass'y

Refer to Fig. 3.12. Remove main P.C.B. ass'y referring to item 3.18. Unplug F06 (Dolby NA P.C.B. ass'y) from main P.C.B. ass'y.

Fig. 3.11

3.20. Meter Ass'y

Refer to Fig. 3.12. Remove front panel ass'y referring to item 3.5. Remove F07 and FOB {meter ass'y)

3.21. Power Switch Ms'y

Refer to Fig. 3.12. Remove main P.C.B. ass'y referring to item 3.18. Remove F09 through F11 (power switch ass'y)

3.22. Record Link Ass'y

Refer to Fig. 3.12. Remove main P.C.B. ass'y referring to item 3.18. Remove F12 and F13 (record !ink ass'y}.

3.23. Rear Panel Ass'y

Refer to Fig. 3.12. Remove cabinet referring to item3.1. Remove F14and F15 (rear panel ass'y).

3.24, Power Supply P.C.B. Ass'y

Refer to Fig. 3.12. Remove cabinet referring to item 3.1. Remove F16 through F18 (power supply P.C.B. ass'y).

3.25. Headphone Jack

Refer to Fig. 3.12. Remove cabinet referring to item 3.1. Remove F19 and F20 (headphone jack).

Fig. 3.12

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4. MEASUREMENT AND MAINTENANCE INSTRUMENT

Note: Refer to item 3 "Removal Procedures".

When a check is made on Amp., etc. by means of an extension cord, re-adjustment shall be made without faif after final installation to the model chass'1s. The check without removal of an extension cord will cause inaccurate adjustments.

(DOLBY NR P.C.BJ

PERSPECTIVE VIEW

Fig. 4 Extension Cord Connection

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4.1.Measurement Instrument

{1) Audio Generator (20 Hz - 200 kHz)

(2)AC Milivo!t Meter (with dB measures)

(3)Oscilloscope {DC - 5 MHz)

(4)Distortion Meter

(5)Speed & Wow/Flutter Meter

(6)Frequency Counter (DC - 1 MHz)

(7)OhmMeter

{8) DC Volt Meter

(9)AC Volt Meter

(10)Tape Travelling Cassette B (part No. DA09027A)

(11)Torque Gauge (DA09013A)

(12)15 kHz Azimuth Tape (DA09004A)

(13)3 kHz Speed & Wow/Flutter Tape (DA09006A)

(14)1 kHz Track Alignment Tape (DA09007A)

(15)400Hz Level Tape (DA09005A)

(16)20 kHz PB Frequency Response Tape (DA09001A)

(17)15 kHz PB Frequency Response Tape (DA09002A)

(18)10 kHz PB Frequency Response Tape {DA09003A}

(19)Reference EXI I Tape (DA09021A)

(20)Reference SX Tape (DA09025A)

(21)Track Viewer (DA09012A)

(22)Tape Guide Adjuster B (OD09011A)

(23)Audio Analyzer T-100

(including Distortion, Wow/Flutter, Speed, Oscillator and dB meter)

(24)Information Terminals, Model M-300 (for positioning of record/playback head)

Note: (10) - (23) are the products of NAKAMICHI RESEARCH INC.

4.2.Maintenance Instrument

Refer to Fig. 4.1 Extension Cord Connection.

(1)Extension cord (10p) {part No. DA09020A)

(2)Extension cord {14p) {DA09016A)

(3)Extension cord (38p) {DA09026B)

5.MECHANICAL ADJUSTMENTS

5.1.Take-up Torque and Rewind Torque Adjustment To adjust torque, move reel hub spring as shown in Fig.

5.1.The take-up torque should be 45 ± 10 g-cm and rewind torque should be 35 to 60 g-cm.

Fig. 5.1

5.2.Tape Speed Adjustment

(1) Connect a frequency counter to the output jack.

(2)Load a 3 kHz Speed Wow/Flutter Tape (DA09006A) and play it back.

(3)Adjust the tape speed adjust potentiometer (acces sible from the rear apron without removing cabinet).

See Fig. 5.2.

VJ

SPEED CAL.'\

~

Fig. 5.2

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