AIWA CX-LFA660, CX-LFA770 Service Manual

CX-LFA660/LFA770

SERVICE MANUAL

Ver. 1.1 2005.10

CX-LFA660/LFA770 are the Amplifier , CD pla yer, Tape
Deck and Tuner section in XR-FA660/FA770.

Photo : CX-LFA660

CD CD Mechanism Type CDM77B-F1BD81A
Section Base Unit Name BU-F1BD81A

TAPE Model Name Using Similar Mechanism NEW
Section Tape Transport Mechanism T ype CMAL1Z240A

AEP Model

UK Model

CX-LFA660/LFA770

Australian Model

CX-LFA660

Model Name Using Similar Mechanism NEW

Optical Pick-up Name KSM-215DCP/C2NP

SPECIFICATIONS

Amplifier section

CX-LFA770 for XR-FA770

DIN power output (rated): 55 + 55 W

(6 ohms at 1 kHz, DIN)

Continuous RMS power output (referen ce):

70 + 70 W
(6 ohms at 1 kHz, 10%
THD)

Music power output (reference):

125 + 125 W

CX-LFA660 for XR-FA660

European model:
DIN power output (rated): 40 + 40 W

(6 ohms at 1 kHz, DIN)

Continuous RMS power output (referen ce):

50 + 50 W
(6 ohms at 1 kHz, 10%
THD)

Music power output (reference):

85 + 85 W
Other models:
The following measured at AC 230 – 240 V, 50/60 Hz
DIN power output (rated): 40 + 40 W

(6 ohms at 1 kHz, DIN)

Continuous RMS power output (referen ce):

50 + 50 W
(6 ohms at 1 kHz, 10%

THD)
Inputs
MD IN (RCA pin jacks): Sensitivity 2 V,

impedance 47 kilohms
Outputs
PHONES (stereo mini jack):

Accepts headphones with

an impedance of 32 ohms

or more
SPEAKER: Accepts impedance of

6ohms

CD player section

Laser Semiconductor laser

(λ=770 – 810 nm)

Emission duration:

continuous
Frequency response 20 Hz – 20 kHz

Tape deck section

Recording system 4-track 2-channel, stereo

— Continued on next page —

9-879-045-02

2005J16-1
© 2005.10

COMPACT DISC DECK RECEIVER

Sony Corporation

Personal Audio Division
Published by Sony Engineering Corporation

CX-LFA660/LFA770

Frequency response 50 – 13,000 Hz (±3 dB),

using Sony TYPE I
cassettes

Tuner section

FM stereo, FM/AM superheterodyne tuner

FM tuner section

Tuning range 87.5 – 108.0 MHz

(50-kHz step)
Antenna FM lead antenna
Antenna terminals 75 ohms unbalanced
Intermediate frequency 10.7 MHz

AM tuner section

European model: 531 – 1,602 kHz

(with the tuning interval

set at 9 kHz)
Other models: 530 – 1,710 kHz

(with the tuning interval

set at 10 kHz)

531 – 1,602 kHz

(with the tuning interval

set at 9 kHz)
Antenna AM loop antenna, external

antenna terminal
Intermediate frequency 450 kHz

General

Power requirements
European model: 230 V AC, 50/60 Hz
Australian model: 230 – 240 V AC, 50/60 Hz
Power consumption
XR-FA770: 75 W

0.3 W (in Power Saving

Mode)
XR-FA660
European model: 65 W

0.3 W (in Power Saving

Mode)
Other models: 70 W
Dimensions (w/h/d) Approx. 190 × 250 × 308

mm incl. projecting parts

and controls
Mass
CX-LFA770 for XR-FA770:

Approx. 6.1 kg
CX-LFA660 for XR-FA660:

Approx. 5.8 kg

Design and specifications are subject to change
without notice.

TABLE OF CONTENTS

1. SERVICING NOTES ................................................ 3

2. GENERAL ................................................................... 5

3. DISASSEMBLY

3-1. Disassembly Flow ........................................................... 8

3-2. Top Cabinet, Tuner (FM/AM), DC Fan.......................... 9

3-3. Panel (DVD) .................................................................... 9

3-4. CD Mechanism Section................................................... 10

3-5. Front Panel Section ......................................................... 10

3-6. MAIN Board.................................................................... 11

3-7. FRONT Board ................................................................. 11

3-8. Cassette Deck Mechanism............................................... 12

3-9. Power Transformer .......................................................... 12

3-10. Tray (AU) ........................................................................ 13

3-11. MS-128 Board ................................................................. 13

3-12. Base Unit, Belt, Driving Gear ......................................... 14

4. TEST MODE ............................................................... 15

5. MECHANICAL ADJUSTMENTS......................... 16

6. ELECTRICAL ADJUSTMENTS .......................... 17

7. DIAGRAMS

7-1. Block Diagram – BD Section –...................................... 22

– MAIN Section – ........................................................... 23

7-2. Printed Wiring Board – BD81A Section – ..................... 24

7-3. Schematic Diagram – BD81A Section –........................ 25

7-4. Printed Wiring Boards – MAIN Section – ..................... 26

7-5. Schematic Diagram – MAIN Section (1/2) –................. 27

7-6. Schematic Diagram – MAIN Section (2/2) –................. 28

7-7. Printed Wiring Board – FRONT Section –..................... 29

7-8. Schematic Diagram – FRONT Section – ....................... 30

7-9. Printed Wiring Board – AMP Section – ......................... 31

7-10. Schematic Diagram – AMP Section – ............................ 32

7-11. Printed Wiring Board – PT Section – ............................. 33

7-12. Schematic Diagram – PT Section –................................ 33

8. EXPLODED VIEWS

8-1. Overall Section ................................................................ 41

8-2. Front Section ................................................................... 42

8-3. Chassis Section................................................................ 43

8-4. CD Mechanism Deck Section (CDM77B-F1BD81A).... 44

8-5. Base Unit (BU-F1BD81A).............................................. 45

9. ELECTRICAL PARTS LIST .................................. 46

2

SECTION 1

SERVICING NOTES

CX-LFA660/LFA770

Notes on chip component replacement

• Never reuse a disconnected chip component.

• Notice that the minus side of a tantalum capacitor may be

damaged by heat.

Flexible Circuit Board Repairing

• Keep the temperature of the soldering iron around 270 °C

during repairing.

• Do not touch the soldering iron on the same conductor of the

circuit board (within 3 times).

• Be careful not to apply force on the conductor when soldering

or unsoldering.

UNLEADED SOLDER

Boards requiring use of unleaded solder are printed with the lead­free mark (LF) indicating the solder contains no lead.
(Caution: Some printed circuit boards may not come printed with

the lead free mark due to their particular size)

: LEAD FREE MARK

Unleaded solder has the following characteristics.

• Unleaded solder melts at a temperature about 40 °C higher

than ordinary solder.
Ordinary soldering irons can be used but the iron tip has to be
applied to the solder joint for a slightly longer time.
Soldering irons using a temperature regulator should be set to
about 350 °C.
Caution: The printed pattern (copper foil) may peel away if

the heated tip is applied for too long, so be careful!

• Strong viscosity

Unleaded solder is more viscou-s (sticky, less prone to flow)
than ordinary solder so use caution not to let solder bridges
occur such as on IC pins, etc.

• Usable with ordinary solder

It is best to use only unleaded solder but unleaded solder may
also be added to ordinary solder.

CAUTION

Use of controls or adjustments or performance of procedures
other than those specified herein may result in hazardous radiation
exposure.

This appliance is classified as a CLASS 1 LASER product.
The CLASS 1 LASER PRODUCT MARKING is located on the
rear exterior.

Laser component in this product is capable of emitting radiation
exceeding the limit for Class 1.

NOTES ON HANDLING THE OPTICAL PICK-UP
BLOCK OR BASE UNIT

The laser diode in the optical pick-up block may suffer electrostatic
break-down because of the potential difference generated by the
charged electrostatic load, etc. on clothing and the human body.
During repair, pay attention to electrostatic break-down and also
use the procedure in the printed matter which is included in the
repair parts.
The flexible board is easily damaged and should be handled with
care.

NOTES ON LASER DIODE EMISSION CHECK

The laser beam on this model is concentrated so as to be focused on
the disc reflective surface by the objective lens in the optical pick­up block. Therefore, when checking the laser diode emission,
observe from more than 30 cm away from the objective lens.

LASER DIODE AND FOCUS SEARCH OPERATION
CHECK

Carry out the “S curve check” in “CD section adjustment” and check
that the S curve waveforms is output three times.

SAFETY-RELATED COMPONENT WARNING!!

COMPONENTS IDENTIFIED BY MARK 0 OR DOTTED LINE
WITH MARK 0 ON THE SCHEMATIC DIAGRAMS AND IN
THE PARTS LIST ARE CRITICAL TO SAFE OPERATION.
REPLACE THESE COMPONENTS WITH SONY PARTS WHOSE
PART NUMBERS APPEAR AS SHOWN IN THIS MANUAL OR
IN SUPPLEMENTS PUBLISHED BY SONY.

MODEL IDENTIFICATION
– Back Panel –

Part No.

Model Name Part No.

AEP and UK models 2-067-053-0[ ]
Australian model 2-067-053-2[ ]

3

CX-LFA660/LFA770

k

• SERVICE POSITION OF THE CD MECHANISM DECK

*

Lay the CX-LFA660/LFA770 with the left-side facing downward and then check the CD mechanism deck after removing it

from the Holder Mech.

MAIN Board

holder mech

CD mechanism deck

• SERVICE POSITION OF THE TAPE CASSETTE MECHANISM DECK

*

Remove the CD mechanism deck and the Holder mech from the unit and check the tape cassette mechanism deck with

the front panel being open.

front panel

tape cassette mechanism dec

4

SECTION 2

Main unit

ALBUM +/– qj (10, 11, 16)
BASS/TRE qa (18)
Cassette compartment qd
CD SYNC wa (16)
Disc tray 6
DISPLAY 8 (14, 21)
Display window 5
i-Bass q; (18)
MD ql (23)

PHONES jack qf
PLAY MODE qs (9, 11, 15, 16,

17)
Remote sensor 7
TUNER/BAND 4 (12, 13)
TUNING +/– qk (12, 13)
TUNING MODE qs (12, 13)
VOLUME control qg (26)

?/1 (power) 1 (7, 13, 26)
TAPE nN (play) 2 (15, 16)
CD NX (play/pause) 3 (9)

Z CD (open/close) 9 (9)
Z PUSH OPEN (tape open/close)

qd (15)

x (stop) qh (10, 12, 15, 16, 26)
m/M (rewind/fast forward)

qk (10, 15)

l/L (go back/go forward)

qk (10, 17, 18)

z REC PAUSE/START (record)

w; (16)

List of button locations and reference pages

How to use this page

Use this page to find the location of buttons and other
parts of the system that are mentioned in the text.

Illustrati

on number

r

DISPLAY

8 (

14, 21

)

RR

Name of button/ pa r t Reference page

ALPHABETICAL ORDER

A – O

P – Z

BUTTON DESCRIPTIONS

1234 567 8

9
q;

qa
qs

qf

qd

qg

qhqjqk

ql

w;

wa

GENERAL

CX-LFA660/LFA770

This section is extracted
from instruction manual.

5

CX-LFA660/LFA770

Remote control

ALPHABETICAL ORDER

A – O P – Z

ALBUM +/– qs (10, 11)
CD qj (9, 11)
CLEAR qf (11)
CLOCK/TIMER SELECT 2

(19, 20)

CLOCK/TIMER SET 3 (8, 19,

20)
DISC SKIP* q;
DISPLAY w; (14, 21)
ENTER 9 (8, 11, 12, 19, 20)
EQ qd (18)
FM MODE 4 (14)
FUNCTION 6 (9, 11, 15, 20, 23)

PLAY MODE ql (9, 11, 15, 20)
REPEAT 4 (10)
SLEEP wa (18)
TAPE qh (15, 20)
TUNER BAND 5 (12, 13)
TUNER MEMORY qk (12)
TUNING MODE ql (12, 13)
VOLUME +/– qa (19)

BUTTON DESCRIPTIONS

?/1 (power) 1 (7, 19)
m/M (rewind/fast forward )

7 (10, 15)

x (stop) 8 (10, 12, 15)
X (pause) 8 (10, 15)
N (play) 8 (9, 15, 20)
./> (go back/go forward)

qg (8, 10, 18, 19)

+/– (tuning) qg (12)
*Button does not function with

this model.

wa
w;

ql
qk
qj
qh
qg

qf
qd

qs

1
2

3
4
5
6

7
8

9
0

qa

6

Setting the clock

Use buttons on th e remote for the operatio n.

1

Press ?/1 to turn on the system.

2

Press CLOCK/TIMER SET.

3

Press . or > rep eatedly to set the
hour.

4

Press ENTER.

5

Press . or > rep eatedly to set the
minute.

6

Press ENTER.

The clock sta rt s working.

To adjust the clock

CX-LFA660/LFA770

1

Press CLOCK/T IM ER SE T.

2

Press . or > repeatedly until “CLOCK”
appears, then press ENTER.

3

Do the same procedures as step 3 to 6
above.

7

CX-LFA660/LFA770

3-1. DISASSEMBLY FLOW

•This set can be disassembled in the order shown below.

SET

SECTION 3

DISASSEMBLY

3-2. T OP CABINET , TUNER (FM/AM),

DC FAN

(Page 9)

3-3. PANEL (DVD)

(Page 9)

3-4. CD MECHANISM SECTION

(Page 10)

3-5. FRONT PANEL SECTION

(Page 10)

3-6. MAIN BOARD

(Page 11)

3-9. POWER TRANSFORMER

(Page 12)

3-10. TRAY (AU)

(Page 13)

3-7. FRONT BOARD

(Page 11)

3-8. CASSETTE DECK MECHANISM

(Page 12)

3-11. MS-128 BOARD

(Page 13)

3-12. BASE UNIT, BELT,

DRIVING GEAR

(Page 14)

8

Note: Follow the disassembly procedure in the numerical order given.

3-2. TOP CABINET, TUNER (FM/AM), DC FAN

5

2

two s

(+BVTP 3

crews

×

8)

top cabinet

b

4

1

two s

(+BVTP 3

crews

a

×

8)

3

five s

qd

DC fan

crews

rear panel

(+BVTP 3

qs

q;

connector

(3P)(CN290)

CX-LFA660/LFA770

×

8)

qa

four s

(+BVTP 3

a

crews

×

8)

6

three s

(+BVTP 3

7

(+BVTP 3

crews

three s

×

10)

crews

×

8)

3-3. PANEL (DVD)

CD mechanism

8

wire (flat type)
(15 core)

b

3

four claws

9

tuner

4

base loading

5

panel (DVD)

chuck cam

2

holder mecha

1

Move the chuck cam located at the bottom of the CD mechanism in the direction of the arrow

using the flathead screwdriver.

Pull-out the disc tray.

9

CX-LFA660/LFA770

)

3-4. CD MECHANISM SECTION

6

CD mechanism deck

(CDM77B-F1BD81A)

8

two s

(+BVTP 3

3

three s

(+BVTP 3

5

wire (flat type) (5 core)

crews

×

crews

8)

1

two s

(+BVTP 2.6

2

shield case (mecha)

×

10)

4

wire (flat type)
(27 core)

9

two s

(+BVTP 3

crews

crews

×

10)

×

8)

q;

holder mecha

3-5. FRONT PANEL SECTION

2

1

screw
(+B 3)

earth wire

5

wire (flat type)

(25core) (CN603)

9

connector

(7P) (CN601)

qd

claw

7

s

crew

(+BVTP 3

×

10

10

qa

two screws
(+KTP 3

qf

front panel section

7

×

8)

screw
(+KTP 3

4

earth wire

3

screw

qs

claw

8

connector

6

wire (flat type)

(21core) (CN602)

×

8)

q;

two screws
(+KTP 3

×

8)

(5P) (CN201)

(+B 3)

3-6. MAIN BOARD

)

2

wire (flat type)

(25core) (CN603)

7

connector

(9P) (CN002)

8

connector

(11P) (CN003)

3

wire (flat type)

(21core) (CN602)

5

connector

(7P) (CN601)

CX-LFA660/LFA770

q;

MAIN board

9

sheet (PWB MAIN)

3-7. FRONT BOARD

1

knob (VOL)

6

connector

(5P) (CN201)

1

connector

(10P) (CN257)

8

w

ire (flat type)

25core (CN802)

q;

FRONT board

4

two s

six s

crews

crews

3

bracket

(+BVTP 3

4

(+BVTP 2.6

×

10)

×

10)

9

w

ire (flat type)

21core (CN801)

6

sheet (protection)

7

w

ire (flat type)

8core (CN803)

5

two s

(+BVTP 2.6

crews

2

three s

crews

×

(+BVTP 3

×

10)

10

11

CX-LFA660/LFA770

)

3-8. CASSETTE DECK MECHANISM

3

cassette deck mechanism

1

four screws
(+BVTP 3

×

10)

3-9. PO WER TRANSFORMER

5

binding band

9

Remove the soldering.

q;

PT board

1

s

(+B 3)

2

earth wire

crew

4

binding band

6

connector

(CN202)

2

earth wire

3

four s

crews

7

(+BVTP 3

8

holder (PWB PT

qa

power transformer

s

crew

×

8)

12

3-10. TRAY (AU)

2

1

Move the Chuck cam in the direction of the arrow.

bottom side

two claws

3

CX-LFA660/LFA770

3-11. MS-128 BOARD

1

belt

4

5

tray (AU)

2

wire (flat type)

(5core) (CN001)

4

MS-128 board

3

four claws

13

CX-LFA660/LFA770

3-12. BASE UNIT, BELT, DRIVING GEAR

4

belt

6

support

8

pulley gear

9

driving gear

5

claw

1

two claws

3

base unit

(BU-F1BD81A)

7

claw

2

14

SECTION 4

TEST MODE

CX-LFA660/LFA770

Note 1: Regarding the notification symbol “R”

Because the number of the operating buttons of this product
are limited, some operations require use of the operating
buttons of the remote commander. When a specific operation
requires use of the operating buttons of the remote commander,
“R” is added to the specific operating procedure in this manual.
Example MENU/NO “R” The MENU/NO button of remote
commander.

Note 2: Incorrect operations may be performed if the test mode is

not entered properly.
In this case, press the ?/1 button to turn the po wer of f, and
retry to enter the test mode.

1. Cold Reset

• The cold reset clears all data including preset data stored in
the RAM to initial conditions. Execute this mode when
returning the set to the customers.

Procedure:

1. Press three buttons x , [VOLUME] (down) and ?/1
simultaneously.

2. When this button is operated, all of the settings are reset.

2. Panel Test Mode

•This mode is used to check the software version, LCD, LED
and keyboard.

Procedure:

1. Press three bottons [DISPLAY], ?/1 and [VOLUME] (down)
simultaneously.

2. When the panel test mode is activated, all se gments are turned
on.

4. Repeat 5 Times Limit Release Mode

Procedure:

1. Press the ?/1 button to turn the power on.

2.

Press three buttons
simultaneously.

3. To exit from this mode, press the ?/1 button.

5. Disc Tray Lock

The disc tray lock function for the antitheft of an demonstration
disc in the store is equipped.

Setting Procedure :

1. Press the ?/1 button to turn the set on.

2. Insert a disc.

3. Press the x button and the Z CD button simultaneously for
five seconds.

4. The message “LOCKED” is displayed and the tray is locked.

Releasing Procedure :

1.

Press the
five seconds again.

2. The message “UNLOCKED” is displayed and the tray is
unlocked.

Note: When “LOCKED” is displayed, the slot lock is not released by

turning power on/off with the ?/1 button.

x , [VOLUME] (down)

x

button and the Z CD button simultaneously

and the [PLAY MODE]

for

2-1. V ersion T est Mode

Procedure:

1. When the panal test mode is activated, press the [BASS/
TREBLE] button and the version is displayed.

2. Press the [i-Bass] button and the date of the software production
is displayed.

3. Press the [BASS/TREBLE] button again and the version is
displayed.

4. To exit from this mode, pull out the AC plug.

2-2. Key Test Mode

Procedure:

1. When the panel test mode is activated, press the [PLAY MODE]
button, to select the key test mode. In the ke y check mode, the
fluorecent indicator displays “KEY 0”. Each time a button is
pressed, “KEY” value increases. However, once a button is
pressed, it is no longer taken into account. When all keys are
pressed correctly, “KEY 19” is displayed.

2. To exit from this mode, pull out the AC plug.

3. Common Test

Procedure:

1. Press the ?/1 button to turn the power on.

2. When the common test mode is activated, each time press the
EQ “R” button, the message “EQ MAX”, “EQ MIN”, “EQ
FLAT” is displayed in this order.

3. The message “Volume MAX” is displayed, when press the
[VOLUME] (up) button or V OLUME + “R” b utton. The mes­sage “Volume MIN” is displayed, when press the [VOLUME]
(down) button or VOLUME – “R” button.

4. To exit from this mode, press the ?/1 button to turn off the
main power.

15

CX-LFA660/LFA770

SECTION 5

MECHANICAL ADJUSTMENTS

Precaution

1. Clean the following parts with a denatured alcohol-moistened
swab:

record/playback heads pinch rollers
erase head rubber belts
capstan idlers

2. Demagnetize the record/playback head with a head demag­netizer.

3. Do not use a magnetized screwdriver for the adjustments.

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

5. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.

Torque Measurement

Mode

FWD

FWD
back tension

REV

REV
back tension

FF/REW

FWD tension

REV tension

Torque meter Meter reading

2.94 – 7.84 mN • m

CQ-102C

CQ-102C

CQ-102RC

CQ-102RC

CQ-201B

CQ-403A

CQ-403R

(30 to 79 g • cm)

(0.42 – 1.11 oz • inch)

0.15 – 0.59 mN • m
(2 to 6 g • cm)

(0.03 – 0.08 oz • inch)

2.94 – 7.84 mN • m

(30 to 79 g • cm)

(0.42 – 1.11 oz • inch)

0.15 – 0.59 mN • m
(2 to 6 g • cm)

(0.03 – 0.08 oz • inch)

6.86 – 17.64 mN • m
(70 to 179 g • cm)

(0.98 – 2.49 oz • inch)

9.8 mN • m or more

(100 g • cm or more)

(1.4 oz • inch or more)

9.8 mN • m or more

(100 g • cm or more)

(1.4 oz • inch or more)

16

SECTION 6

ELECTRICAL ADJUSTMENTS

CX-LFA660/LFA770

DECK SECTION 0 dB=0.775V

1. Demagnetize the record/playback head with a head
demagnetizer.

2. Do not use a magnetized screwdriver for the adjustments.

3. After the adjustments, apply suitable locking compound to
the parts adjusted.

4. The adjustments should be performed with the rated power
supply voltage unless otherwise noted.

5. The adjustments should be performed in the order given in
this service manual. (As a general rule, playback circuit
adjustment should be completed before performing recording
circuit adjustment.)

6. The adjustments should be performed for both L-CH and R­CH.

7. Switches and controls should be set as follows unless otherwise
specified.

Signal Used forTape

P-4-A100

WS-48B

[Record/Playback Head Azimuth Adjustment]

Procedure:

1. Mode : Playback

test tape
P-4-A100
(10kHz, –10dB)

10 kHz, –10 dB

3 kHz, 0 dB

MAIN board
J201
speaker terminal

Azimuth Adjustment

Tape Speed Adjustment

level meter

3. Mode: Playback

test tape
P-4-A100
(10kHz, –10dB)

set

in phase 45

MAIN board
J201
speaker terminal

L

R

Waveform of oscilloscope

°

90

°

good

135

oscilloscope

°

wrong

180

°

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

Adjustment Location: Record/Playback/Erase Head

set

+
–

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 1 dB of peak.

L-CH
peak

screw
position

R-CH
peak

output
level

within
1 dB

L-CH
peak

R-CH
peak

within 1dB

screw
position

adjustment screw

[Tape Speed Check]

Procedure:

1. Turn the power on.

2. Insert the WS-48B into deck.

3. Press the TAPE nN button of deck.

4. Check the reading of frequency counter becomes 3000 ± 90

Hz.

Sample Value of Wow and flutter

W.RMS (JIS) less than 0.3%
(test tape: WS-48B)

17

CX-LFA660/LFA770

CD SECTION

Note:

1. Use YEDS-18 disc (3-702-101-01) unless otherwise indicated.

2. Use an oscilloscope with more than 10MΩ 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.

S-curve Check

Connection:

oscilloscope

BD81A board

TP (FEO)

TP (VC)

Procedure:

1. Connect an oscilloscope to test point TP (FEO) and TP (VC)

on the BD81A board.

2. Turn the power on.

3. Put the disc (YEDS-18) in and press the 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

+
–

symmetry

A

B

CD

NX

within 2

±

1 Vp-p

RFDC signal waveform

VOLT/DIV: 200 mV
TIME/DIV: 500 ns

±

level: 0.6

0.15 Vp-p

Checking Location: BD81A board (Side B)

RFAC Level Check

Connection:

oscilloscope

BD81A board

TP (RFACO)

TP (VC)

+
–

Procedure:

1. Connect an oscilloscope to test point TP (RF ACO) and TP
(VC) on the BD81A 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.

Note:

A clear RFAC signal waveform means that the shape “◊” can be
clearly distinguished at the center of the waveform.

RFAC signal waveform

VOLT/DIV: 200 mV
TIME/DIV: 500 ns

Note:

•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: BD81A board (Side B)

RFDC Le

vel Check

Connection:

oscilloscope

BD81A board

TP (RFDCO)

TP (VC)

+
–

Procedure:

1. Connect an oscilloscope to test point (RFDCO) and TP (VC)
on the BD81A board.

2. Turn the power on.

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

4. Confirm that oscilloscope wav eform is clear and check RFDC
signal level is correct or not.

A clear RFDC signal waveform means that the shape “◊” can be

Note:

clearly distinguished at the center of the waveform.

Checking Location: BD81A board (Side B)

level: 1.0

±

0.4 Vp-p

18