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13

Mode: Playback

1. Insert the WS-48B into the deck.
2. Press the TAPE N button on the deck.
3. Confirm that the frequency counter reads 3,000 

±

 90 Hz.

Sample value of Wow and Flutter: 0.3% or less W.RMS (JIS)

(WS-48B)

2. Turn the adjustment screw and check output peaks. If the peaks

do not match for L-CH and R-CH, turn the adjustment screw
so that outputs match within 1dB of peak.

3. Mode: Playback

4. After the adjustments, apply suitable locking compound to the

parts adjusted.

Screw
position

L-CH
peak

within
1dB

Output
level

L-CH
peak

R-CH
peak

within
1dB

Screw
position

R-CH
peak

set

test tape
P-4-A100
(10 kHz, – 10 dB)

R-CH

oscilloscope

L-CH

R-CH

V

H

waveform of oscilloscope

in phase 45

°

90

°

135

°

180

°

good

wrong

MAIN board
SPEAKER terminal (J302)
L-CH

+
–

set

test tape
WS-48B 
(3 kHz, 0 dB)

MAIN board
SPEAKER terminal (J302)
L-CH, R-CH

frequency counter

Procedure:
1. Mode: Playback

Adjustment Location: Record/Playback/Erase Head

set

MAIN board
SPEAKER terminal (J302)
L-CH, R-CH

+
–

level meter

test tape
P-4-A100
(10 kHz, – 10 dB)

Note: Refer to “3-6. Cassette Door Assy” (see page 10)

adjustment screw

14

       RFDC signal waveform

Checking Location: CD board (Conductor side)

1. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.
2. Use an oscilloscope with more than 10M

Ω

 impedance.

3. Clean the object lens by an applicator with neutral detergent when the

signal level is low than specified value with the following checks.

Procedure:
1.

Connect an oscilloscope to test point TP (RFDC) and TP (VC)
on the BD board.

2.

Turn the power on.

3.

Put the disc (YEDS-18) in to playback the number five track.

4.

Confirm that oscilloscope waveform is clear and check RFDC
signal level is correct or not.

A clear RFDC signal waveform means that the shape “

◊

” can be

clearly distinguished at the center of the waveform.

+
–

BD board

TP (RFDC)

TP (VC)

oscilloscope

VOLT/DIV: 200 mV
TIME/DIV: 500 ns 

level: 0.6 

±

 0.15 Vp-p

Procedure:
1.

Connect an oscilloscope to test point TP (RFAC) and TP (VC)
on the BD board.

2.

Turn the power on.

3.

Put the disc (YEDS-18) in to playback the number five track.

4.

Confirm that oscilloscope waveform is clear and check RFAC
signal level is correct or not.

A clear RFAC signal waveform means that the shape “

◊

” can be

clearly distinguished at the center of the waveform.

       RFAC signal waveform

Checking Location: BD board (Side B)

+
–

BD board

TP (RFAC)

TP (VC)

oscilloscope

VOLT/DIV: 200 mV
TIME/DIV: 500 ns 

level: 1.0 

±

 0.4 Vp-p

Procedure:
1.

Connect an oscilloscope to test point TP (FE) and TP (VC)
on the BD board.

2.

While depressing the  CD        button, insert an AC plug.

3.

Put the disc (YEDS-18) in and press the  STOP     button 
and actuate the focus search. (actuate the focus search when
disc table is moving in and out)

4.

Check the oscilloscope waveform (S-curve) is symmetrical
between A and B. And confirm peak to peak level within 2 

±

 1

Vp-p.

S-curve waveform

• Try to measure several times to make sure than the ratio of A : B

or B : A is more than 10 : 7.

• Take sweep time as long as possible and light up the

brightness to obtain best waveform.

Checking Location: BD board (Side B)

+
–

BD board

TP (FE)

TP (VC)

oscilloscope

A

B

symmetry

within 2 

±

 1 Vp-p

u

x

15

Checking Location: BD board (Side B)

+
–

BD board

TP (TE)

TP (VC)

oscilloscope

Traverse Waveform

0V

B

level: 1.0 

±

 0.5 Vp-p

Center of 
the waveform

A (DC 

voltage)

Traverse Waveform

0V

Tracking servo

Sled servo

ON

C (DC 
voltage)

Tracking servo

Sled servo

OFF

6.

Press the        

CD u

  button. (The trac

king servo and sledding

servo are turned ON)
Rotate RV101 on BD board and adjust the C (DC voltage) 
is almost equal to the A (DC voltage) in step 4. 

7. To exit from this mode, turn the power off.

• Always move the optical pick-up to most inside track when

exiting from this mode. Otherwise, a disc will not be unloaded.

• Do not run the sled motor excessively, otherwise the gear can

be chipped.

Procedure:
1.

Connect an oscilloscpe to test point TP (TE) and TP (VC) on
the BD board.

2.

While depressing the

CD u

  button, insert an AC plug to

enter the CD test mode.

3.

Put the disc (YEDS-18) in to playback the number five track.

4.

Press the                   button. If it plays, press the             

CD u

again. (The tracking servo and the sledding servo are
turned OFF)

5.

Check the level B of the oscilliscope's waveform and the A
(DC voltage) of the center of the Traverse waveform.
Confirm the following :
A/B x 100 = less than 

±

 10%

CD u

  

 button

IC101

TP7
(VC)

IC103

RV101
E-F Balance
Adjustment

  TP8
(RFAC)

  TP6
(RFDC)

TP4
(FE)

TP2
(TE)

16

BD board

MAIN board

REGULATOR board

POWER board

CONTROL board

SUB-CONTROL board

Note:
• All capacitors are in 

µ

F unless otherwise noted.  pF: 

µµ

F

50 WV or less are not indicated except for electrolytics
and tantalums.

• All resistors are in 

Ω

 and 

1

/

4

 

W or less unless otherwise

specified.

•

f

: internal component.

•

2

: nonflammable resistor.

•

1

: fusible resistor.

•

C

: panel designation.

• X

: parts extracted from the component side.

• Y

: parts extracted from the conductor side.

•

f

: internal component.

•

: Pattern from the side which enables seeing.

•

A

: B+ Line.

•

B

: B– Line.

• Voltages are taken with a VOM (Input impedance 10 M

Ω

).

Voltage variations may be noted due to normal produc-
tion tolerances.

• Waveforms are taken with a oscilloscope.

Voltage variations may be noted due to normal produc-
tion tolerances.

• Circled numbers refer to waveforms.

• Signal path.

F

: TUNER

J

: CD

d

: AUX

E

: PB (TAPE)

a

: REC (TAPE)

Note: The components identified by mark 

0

 or dotted line

with mark 

0

 are critical for safety.

Replace only with part number specified.