Sony CDP-502ESII User manual

ERVICE MANUAL
Photo: CDP-650ESDII
Refer to RM-D302/D502 Service Manual issued separately for
information of the remote controller supplied with this set.
CDP-620ESII/650ESDII:
US Model
Canadian Model
CDP-502ESII/552ESDI:
AEP Model
UK Model
E Model
SPECIFICATIONS
System Compact disc digital audio system Outputs Line outputs
Disc Compact disc FIXED (phono jacks)
Laser Semiconductor laser (A = 780 nm) Output level 2 V rms (at MSB)
Laser output Max. 0.4 mW * Load impedance over 10 kilohms
* This output is the value measured at a distance of
about 1.6 mm from the objective lens surface on the
Optical Pick-up Block.
200 r.p.m. to 500 r.p.m. (CLV)
1.2- 1.4 misec.
Sony Super Strategy Cross Interleave
Reed Solomon Code
Spindle speed
Scan velocity
Errorcorrection
Number of channels
2
D-A conversion 16-bit linear
Frequency responce
2 - 20,000 Hz + 0.5 dB
Harmonic distortion
Less than 0.0025% (1 kHz)
Dynamic range More than 96 dB
Channel separation
More than 95 dB (1 KHz)
Wow and flutter Below measurable limit
SAFETY-RELATED COMPONENT WARNING!!
COMPONENTS IDENTIFIED BY SHADING AND MARK
A\ 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.
|
MICROFILM
VARIABLE (phone jacks)
Max. output level 2 V rms (at MSB)
Load impedance over 50 kilohms
Headphones (stereo phone jack)
28 mW at 32 ohms
CDP-552ESDII/650ESDII:
DIGITAL OUT (phono jacks)
Max. output level 0.5 Vp-p
Load impedance 75 ohms
— Continued on page 2 —
ATTENTION AU COMPOSANT AYANT RAPPORT
A LA SECURITE!
LES COMPOSANTS IDENTIFIES PAR UNE TRAME ET
UNE MARQUE /\ SUR LES DIAGRAMMES SCHE-
MATIQUES ET LA LISTE DES PIECES SONT CRITIQUES
POUR LA SECURITE DE FONCTIONNEMENT. NE REM-
PLACER CES COMPOSANTS QUE PAR DES PIECES
SONY DONT LES NUMEROS SONT DONNES DANS CE
MANUEL OU DANS LES SUPPLEMENTS PUBLIES PAR
COMPACT DISK PLAYER
SONY.
AUD

CDP-502ESII/55 2ESDII/620ESII/650ESDII
Disc
Track pitch 1.6 um
Sampling frequency
44.1 kHz
Quantization 16 bit linear quantizing/channel
Modulation system
EFM
Transfer rate 2.03 Mbit/sec. (before modulation)
General
Power requirements
US/Canadian model: 120 V AC, 60 Hz
AEP model: 220 V ac (or 240 V ac adjustable by
Sony personnel), 50/60 Hz
UK model: 240 V ac (or 220 V ac adjustable by
Sony personnel), 50 Hz
E model: 110, 120, 220 or 240 V adjustable,
50/60 Hz
Power consumption
16W
CDP-502ESII/620ESII:
Approx. 430 x 85 x 335 mm (w/h/d)
(17 x 33/, x 131/, inches)
including projecting parts and controls
CDP-552ESDII/650ESDO:
Approx. 430 x 85 x 365 mm (w/h/d)
(17 x 34/5 x 143/, inches)
including projecting parts and controls
Weight CDP-502ESII/620ESI:
Approx. 8.5 kg (18 Ibs, 12 02), net
CDP-552ESDII/650ESDI:
Approx. 9.3 kg (20 Ibs, 8 oz), net
Dimensions
FEATURES
¢ High performance and high fidelity.
Direct digital signal output provides for the highest
possible sound quality, when this unit is connected to an
external D/A converter. (CDP-552ESDII/650ESDII)
* Feather-touch function buttons for direct mode change.
© Linear motor for quick selection search.
° A variety of playing modes: CONTINUE mode, PROGRAM
mode and SINGLE mode.
¢ Index function for quick location of the part you want.
¢ Repeat function for one selection, the whole disc,
programmed selections, selections with random order or a
particular portion.
* Auto delay function allows you to delay the playback of the
first selection 2 seconds.
TABLE OF CONTENTS
Section Title Page
Specifications: iio. de de as Ew BE 1
B@atures 02. ¢ dish Roads Pee nh es SS 2
Model Identification ................4.. 3
Safety Check-Out .......0...0.....0.04. 3
Protection of Eyes from Laser Beam
During Servicing... 2... 0.0... eee 4
Servicing Note ............ 0.000002 eee 5
Caution for Electrostatic Breakdown ........ 6
Flow Chart of BU-1C (Base Unit)
Troubleshooting... ............0000085 7
Function of Controls..............00004 9
Notes on Compact Discs ................ 11
SECTION 1 OUTLINE
1-1. Circuit Description ................ 12
1-2. Block Diagram ................... 15
SECTION 2 DISASSEMBLY ............. 17
SECTION 3 ADJUSTMENTS
3-1. Mechanical Adjustment ............. 2
3-2. Electrical Adjustments.............. 2
SECTION 4 DIAGRAMS
4-1. BU-1C (Base Unit) Section
Mounting Diagram ................ 25
4-2. CDP-502ESI/620EST
Mounting Diagram ................ 28
4-3. CDP-502ESH/620ES0
Schematic Diagram ................ 3)
4-4. CDP-552ESDII/650ESDI
Mounting Diagram ................ 38
4-5. CDP-552ESDII/650ESDII
Schematic Diagram ................ 43
4-6. Power Supply Section Mounting Diagram
and Schematic Diagram ............. 4
SECTIONS EXPLODED VIEWS AND
PARTS LIST .............. 33
SECTION 6 ELECTRICAL PARTS LIST.... 6!

CDP-502ESII/55 2ESDII/620ESII/650ESDII
MODEL IDENTIFICATION
— Specification Labels —
CDP-502ESII/620ESI:
US, Canadian model: CDP-620ESI
AEP, UK, E model: CDP-502ESII
SONY: MODEL NO, KS
COMPACT DISK PLAYER
WLLL
SERIAL NO.
MADE IN JAPAN
US, Canadian model: AC: 120 V~ 60 Hz 16W
AEP model: AC: 220 V ~ 50/60 Hz 16 W
UK model: AC: 240 V ~ 50/60 Hz 16 W
E model: AC: 110, 120, 220, 240 V ~ 50/60 Hz 16 W
CDP-552ESDII/650ESDH:
US, Canadian model: CDP-650ESDII
AEP, UK, E model: CDP-552ESDI
SONY: MODEL NO. RSS
COMPACT DISK PLAYER
WLLL LLL
SERIAL NO.
MADE IN JAPAN
US, Canadian model: AC: 120 V ~60Hz 16W
AEP model: AC: 220 V ~ 50/60 Hz 16 W
UK model: AC: 240 V ~ 50/60 Hz 16 W
E model: AC: 110, 120, 220, 240 V ~ 50/60 Hz 16 W
SAFETY CHECK-OUT (US Model)
After correcting the original service problem,
perform the following safety check before releasing
the set to the customer:
Check the antenna terminals, metal trim, ‘‘metallized”’
knobs, screws, and all other exposed metal parts for
AC leakage. Check leakage as described below.
LEAKAGE TEST
The AC leakage from any exposed metal part to
earth ground and from all exposed metal parts to any
exposed metal part having a return to chassis, must
not exceed 0.5mA (500 microampers). Leakage
current can be measured by any one of three
methods.
1. A commercial leakage tester, such as the
Simpson 229 or RCA WT-540A. Follow the
manufacturers’ instructions to use these instru-
ments.
2. <A battery-operated AC milliammeter. The Data
Precision 245 digital multimeter is suitable for
this job.
3. Measuring the voltage drop across a resistor by
means of a VOM or battery-operated AC volt-
meter. The “limit” indication is 0.75 V, so
analog meters must have an accurate low-
voltage scale. The Simpson 250 and Sanwa
SH-63Trd are examples of a passive VOM that
is suitable. Nearly all battery operated digital
multimeters that have a 2V AC range are
suitable. (See Fig. A)
To Exposed Metal
Parts on Set
AC
0.15 uF S1.5k9 voltmeter
{0.75 V)
= Earth Ground
Fig. A. Using an AC voltmeter to check AC leakage.

CDP-502ES/I/55 2ESDII/620ESII/650ESDII
PROTECTION OF EYES FROM LASER BEAM DURING SERVICING
This set employs a laser. Therefore, be sure to fol-
low carefully the instructions below when servicing.
WARNING !!
WHEN SERVICING, DO NOT APPROACH THE LASER
EXIT WITH THE EYE TOO CLOSELY. !N CASE IT IS
NECESSARY TO CONFIRM LASER BEAM EMISSION,
BE SURE TO OBSERVE FROM A DISTANCE OF MORE
THAN 25 cm FROM THE SURFACE OF THE OBJECTIVE
LENS ON THE OPTICAL PICK-UP BLOCK.
CAUTION:
The use of optical instrument with this product will
increase eye hazard.
CAUTION
Use of controls or adjustments or performance
of procedures other than those specified herein
may result in hazardous radiation exposure.
SSS SHORES S HB e Te Here re resese rere
1. Laser Diode Properties
Material: GaAlAs
Wavelength: 780 nm
Emission Duration: continuous
Laser Output: max. 0.4 mW*
e
e
e
e
* This output is the value measured at a distance of
about 1.6mm from the objective lens surface on
the Optical Pick-up Block.
@ Classification: Class Mb
2. During service, do not take the Optical Pick-up
Block apart, and do not adjust the APC circuit.
If there is a breakdown in the APC circuit (includ-
ing laser diode), replace the entire Optiocal Pick-
up Block (including APC borad).
Oe
BESKYTTELSE AF @JNE MOD LASERSTRALING UNDER SERVICE
I dette apparat anvendes laserlys. Derfor skal
nedenstaende instruktioner naje folges under service.
Folg iovrigt instruktionerne i servicemanualen.
ADVARSEL!!
Under service ma gjnene ikke komme nzr objektiv-linsen
pa den optiske pick-up enhed. | tilfzelde af at det er
ngdvendigt at kontrollere udsendelsen af laserlys, skal
det ske i en afstand af mere end 25cm fra den optiske
pick-up.
LASER ADVARSEL MARKNING
Folgende mzrkning findes indvendig i apparatet:
1. Advarsel Mzerkning
CAUTION
AND INTERLOCKS OEFEATED
ADVARSEL :
: INVISIBLE LASER RADIATION WHEN OPEN
AVOID EXPOSURE TO BEAM.
USYNLIG LASERSTRALING VEO ABNING
NAR SIKKERHEDSAFBAYOERE ER UDE AF FUNKTION UNOGA
UDSATTELSE FOR STRALING.
te
7
1. Laser-didoe data
@ Materiale: GaAlAs
@ Belgelengde: 780 nm
@ Udstraling: Kontinuerlig
@ Laseroutput: Max. 0,4 mW*
* Malt i 1,6 mm afstand fra overfladen af objektiv-
linsen pa den optiske pick-up enhed.
@ Klassifikation: Klasse Mb.
2. Adskil aldrig den optiske pick-up enhed under
service, og juster ikke APC kredslebet (Automatic
Power Control). Hvis APC kredslebet (incl. laser-
dioden) bryder ned, skal hele den optiske pick-up
enhed (incl. APC printkortet) udskiftes.
RR me eee meee eee eee et eee
VAROITUS: Laite sisaltaa, laserdiodin, joka lahettia
(nakymatonta) silmille vaarallista lasersateilya.

CDP-502ESII/55 2ES DII/620ESII/650ESDII
— SERVICING NOTE —
A transit lever is provided at the bottom of the unit to protect the
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 pick-up block. There-
fore, when checking the laser diode emission, observe
more than 25 cm away from the objective lens.
LASER DIODE AND FOCUS SERCH OPERA-
TION CHECK
1. Make POWER switch on with no disc inserted and
disc table closed.
2. Confirm that the following operation at right is
performed while observing the objective lens.
@ Hold down optical pick-up block and
chucking arm by a finger.
==
Es
chucking arm
optical pick-up ~
— Se
> —
C2) Confirm that laser beam is spread.
(3) Up and down motion of the objective
lens. (3 times)
optical system against shock during transportation.
Before starting
repairing, make following procedures.
Screwdriver
Bottom Slot
=
=
Screw (red) Transit lever
1. Loosen the screw (red) with the screwdriver.
2 __=Insert the screwdriver into the slot in the lever and
move it in the direction of the arrow until it stops.
3 Tighten the screw.
NOTES ON IC REPLACEMENT
@ When replacing IC401, 501, first clean the IC head
and the inside of the heat sink with alcohol, then
mount the heat sink and fill the heat sink indented
portion with an epoxy type adhesive*, as shown
in the illustration below.
* Epoxy type adhesive: Sony bond SC1000 or other
quick drying 2 liquid compound.
epoxy adhesive
—— 1C
: l
protruding |
section i >
Is
|
|
pas
heat sink

CDP-502ESII/55 2ESDII/620ESII/650ESDII
— CAUTION FOR ELECTROSTATIC BREAKDOWN —
NOTES ON HANDLING THE BASE UNIT (BU-1C)
The
laser
diode
in
the
optical
pick-up
block
may
1.
Place
a
conductive
sheet
on
the
workbench.
suffer
electrostatic
breakdown
because
of
the
poten-
(The
black
sheet
used
as
repair
parts
wrapping).
tial
difference
generated
by
the
charged
electrostatic
2.
Place
the
set
on
the
conductive
sheet.
so
that
the
load, etc. on clothing and the human body.
The printed matter below is included in the repair
parts. During repair, use the procedure in the printed
chassis
touches
the
sheet.
(This
makes
it
the
same
potential
as
the
conductive
sheet).
3.
Place
your
hands
on
the
conductive
sheet.
(This
matter.
The
following
method
is
an
example
for
reference
makes
them
the
same
potential
as
the
sheet).
purposes:
4.
Remove
the
optical
pick-up
block.
5.
Perfrom
work
on
top
of
the
conductive
sheet.
Be
careful
that
clothing
does
not
touch
the
optical
pick-up
block.
Printed Matter Included in the Repair Parts
When
opening
or
repairing
a
BU-1C,
the
procedure
for
grounding
as
follows
is
required
to
prevent
damage
caused
by
static
electricity.
1. Grounding for the human body.
Be
sure
to
put
on
a
wrist-strap
for
grounding
(with
impedance
lower
than
10°Q2)
whose
other
end
is
grounded
The
strap
works
to
drain
away
the
static
electricity
built-up
on
the
human
body.
2. Grounding for the work table.
Be
sure
to
lay
on
the
table
a
cunductive
sheet
(with
impedance
lower
than
10°92)
such
as
sheet
of
copper
which is grounded.
3.
As
static
electricity
built-up
on
clothes
is
not
drained
away,
be
careful
not
to
let
your
clothes
touch
the
BU-IC.
Wrist-strap
for grounding
transit protective cap
The unit
BU-1C.
@) Conductive sheet

CDP-502ESII/55 2ESDII/620ESII/650ESDII
CDP-502ESII/55
2ESDII/620ESII/650ESDII
FLOW CHART OF BU-1C (BASE UNIT)
TROUBLESHOOTING
® Confirm all connectors around BU-1C (base unit)
are secured before the following check.
[SERVO BOARD]
POWER ON
IS OPTICAL o
PICK-UP SET AT SLED MOTOR DRIVE CIRCUIT
INNERMOST IS —1.4 VOLTAGE OUTPUT AT THE EMITTERS ‘
CIRCUMFER- OF Q205 AND.Q206?
ENCE?
DO NOT OBSERVE LASER BEAM |
NEAR THE OBJECTIVE LENS.
CHECK opera. BE SURE TO OBSERVE MORE
Dee miee eco: THAN 25 CM AWAY ee
DOES LASER |
De AGe EGR NO ARE +B (+5 V) AND —B (—5 V) VOLTAGES |
SEE ae TION APPLIED TO BU-1C (BASE UNIT)? 1
CHECK. |
YES
@fis THE VOLTAGE NO |
OF IC303 (ss PJ Pee
TERMINAL @5) +5 v? )
4) YES
FOCUS COIL DRIVE CIRCUIT |
DOES FOC
@SEARCH EpeRRTER c NG 1S VOLTAGE OUTPUT APPLIED TO EMITTERS | NO |
“SEE PAGE 5 FOR OF Q201 AND 202? +1 —--—---->.-
etal Ske gel (THREE CYCLE search’ \—7\ 7 \
OPERATION IS SHOWN.) |
YES |
|
© |
- |
<D0ES
DISC
MOTOR
NO
CHECK
FOK
SIGNAL.
2
|
<ROTATE?
IS
THE
VOLTAGE
OF
THE
BASE
OF
Q303
4.8
v?
|
|
Gee VES 1§ THE VOLTAGE |
OF 1C306 TERMINAL —->+|
READ TOC
INFORMATION
CHECK OPERA.
TION WITH
DISC INSERTED.
CONFIRM THAT NO
< Toc IS READ.
are PAGE 8.
= DETECTION CIRCUIT
OPERATION CHECK.
CONFIRM THAT THE WAVEFORM
BELOW IS OBSERVED.
SEE PAGE 12 FOR CONFIRMING
PROCEDURE.
eae
=F
SCRATCH WIDTH
YES
BU-1C OPERATION
CHECK IS OVER.
@ -0.7 v?
YES
CHECK RF SIGNAL.
CONFIRM THAT THE WAVEFORM BELOW IS
OBSERVED.
RF SIGNAL WAVEFORM. (ay
|
|
|
|
|
|
ARR |
OOO OOK A
4.4,9.0.0.0.0000.004, 1Vp-p
HERR | 0.3V
|
|
1
I
THE DIAMOND SHAPE (0) IN
THE CENTER OF THE WAVEFORM
SHOULD BE CLEARLY DISTINGUISHED.
NO
REPLAC
CHECK
BU-1C.
THE
SET.
6
(SPL)
BU-1C (BASE UNIT)
5 2 2 8] 4 3
(FOK)
(—5V)
(+5V)
(SD)
(FD)
(LD
ON)
CHECKING TOC INFORMATION READING
If TOC information is read correctly, the number
of selections on the disc and the total playing time
will be displayed.
The display will be as follows for YEDS-1.
i fa Ie
1 Ll i | eee eee ieee
SECOND
TRACK MINUTE
% the number of selections \ total playing time

CDP-502ESII/55 2ESDII/620ESII/650ESDII
CDP-502ESII/55 2ES DII/620ESII/650ESDII
FUNCTION OF CONTROLS
eon DIGITAL
[1) [12]
mains
CDP-552ESDII/650ESDI:
LINE OUT
CDP-502ESI/620ESII:
[13] (14) (15) (16) 17] (18) (49) (20) (2a)
[pista _ouT | |
ah
©, i
Front panel
1
2
|
=
~—
co
o
Ess
= o
[11] pry
=
Lad
=
w
= =
[15]
=
-i]
=]
= co
=
wo
POWER switch
Disc compartment
Place a compact disc here.
OPEN/CLOSE button
Display window
Direct selection buttons
Select the desired selection directly by number.
ii PAUSE button and indicator
Press to pause during play. To release the pause mode,
press it again.
p& PLAY button and indicator
AMS (Automatic Music Sensor) buttons
Press to search for the desired selection.
INDEX buttons
Press to search for a particular index number to begin
playback at that point.
Manual search buttons
Press to search for the desired portion of the selection.
TIMER switch
Slide to play back when using the timer available
optionally.
HEADPHONES jack (stereo phone jack)
Remote sensor and indicator (for remote control)
Picks up the infrared transmitting signal from the
supplied remote commander.
REPEAT programming buttons
Press to repeat play. There are five types of repeat play:
one selection, all selections, A <> B, program and shuffle
repeat.
TIME (elapsed or remaining time) button
Shows the elapsed time, the remaining time on both the
selection being played and the whole disc.
AUTO DELAY button
Inserts two seconds of blank space before the beginning
of each selection.
SHUFFLE PLAY button
Press to play selections in a random order.
CLEAR button
Press to clear the programmed selections.
CHECK button
Press to check the order of the programmed selections.
nN
o
w STOP button
[21] PLAY MODE buttons
PROGRAM button: Press to play the programmed
selections.
SINGLE button: Press to play one selection.
CONTINUE buttuon: Press to play from the first (or
desired) selection to the last selection.
NR
[22] LINE OUT/ () PHONE LEVEL (headphone level)
control
Adjusts the output levels for LINE OUT jacks on the rear
panel or the HEADPHONES jack on the front panel.
Display window
3} DISC indicator
Lights up when the disc compartment is closed with a
disc in place or when the disc compartment is opened.
iad
DX)
>
TRACK indicator
Shows the track number of the selection being played.
[25] PGM (program) indicator
Lights up while programming is being done and while
checking the programmed order.
nN 6) INDEX indicator
Displays the index number of the selection being played.
RO ~
Music calender display window
Displays disc selection numbers up to 20 selections.
i) 8] Time counter
Shows the elapsed time the selection has been played.
nN
o
REPEAT indicator
Lights up during repeat play.
w
0) AUTO DELAY indicator
Lights up when the AUTO DELAY button is pressed.
[=]
[31] SHUFFLE PLAY indicator
Lights up when the SHUFFLE PLAY button is pressed.
3]
OVER indicator
Lights up when a disc with more than 20 selections is
inserted.

CDP-502ESII/55 2ESDII/620ESII/650ESDII
The illustration on page 3 shows the model available in
European countries.
33] LINE OUT jacks
FIXED: Output level is constant.
VARIABLE: Output level can be changed with the LINE
OUT contro! and supplied remote commander.
34) DIGITAL OUT jack
Directly outputs the digital audio and subcode data read
from the disc.
Connect to the DIGITAL IN jack of an optional DAS-702ES
D/A converter unit.
35| DIGITAL OUT switch
Slide to select the output signal from the DIGITAL OUT
jack.
ON: for audio and subcode data output
ON (FOR AUDIO USE): for audio data output only. Set to
this position when listening to music through a
connected D/A converter unit.
OFF: for no digital data output. Set to this position when
listening to music through the LINE OUT jacks.
AC power cord
SUBCODE OUT connector
This connector is provided to extend the utility of this
compact disc player by allowing for the connection of
optional equipment which will be available in the future.
NOTES ON COMPACT DISCS
Handle the disc by its edge, and to keep the disc clean, do
not touch the rainbow colored surface.
Not this way
Do not expose the disc to direct sunlight or heat sources
such as hot air ducts, or leave it in a car parked in direct
sunlight where there can be a considerable rise in the
temperature.
Before playing, clean the disc with the cleaning cloth.
Wipe the disc from the center out.
Do not use solvents such as benzine, thinner, commercially
available cleaners or anti-static spray intended for analog
discs.
After playing, store the disc in its case.

CDP-5072ESII/55 2ESDII/620ESII/650ESDII
SECTION 1
OUTLINE
1-1. CIRCUIT DESCRIPTION
The circuits on this set are almost the same as
those on CDP-502ES/620ES and CDP-552ESD/
650ESD, which is already on the market. Therefore,
only the dropout detection circuit and mechanism
control IC (IC303), which change base unit BU-1 to
BU-IC, will be explained here. Refer to the circuit
descriptions in the CDP-502ES/620ES and CDP-
552ESD/650ESD Service Manual for other portions.
1. Dropout Detection Circuit
This circuit is on the base unit BU-1C RF board.
If there are any bubbles or scratches made on the disc
when it is produced, these will adversely affect
tracking, or focus servo, when the disc is played, This
will cause mechanical noise to be generated from the
pick-up, sound skipping, or electrical noise. This cir-
cuit detects these bubbles and scratches, and the out-
put then lowers tracking gain or focus gain loop gain
to prevent these problems.
{RF BOARD) ‘“'-
Next the operation will be explained. Please look
at Fig. 1. During PLAY, the RF signal output from
IC101 pin G) is applied to D101 via IC102-1 buffer.
This RF signal is envelope wave detected at D101.
Therefore, during normal operation (no bubbles or
scratches on the disc) D101 cathode side has a DC
component. Bias is applied via D103 and R115 so
that IC102-2 comparator output is low at this time.
D102, R114 and C113 perform the role of adjusting
auto bias relative to RF signal level fluctuation and
also act as a smoothing circuit so that IC102-2 bias
dose not change even if there is dropout.
Then, if there are bubbles or scratches, the RF
signal is cut, and IC102-2 pin (2) voltage goes lower
than that of IC102-2 pin @) via C111, and during
this period, comparator output IC102-2 pin q@) is in-
verted and becomes high. This signal switches IC203
switch, and tracking gain and focus gain loop gain are
lowered.
IMAIN BOARD)
10101
CX20109
1€102-1
BUFFER
TP102
wD 8103
10%
\—— Dropout Detection Circuit
+5
1€102-2
COMPARATOR
10201
CX20108
ero
HD14053BFP
GAIN DOWN SWITCH
Connect to @ side at ‘’L’’.
Connect to O side at ‘’H”’.
Fig. 1 Dropout Detection Circuit and Gain Down Switch Circuit
@ Ic102 @
(RF signal)
@ Ic102 (2)
@ Ic102 @G)
© D209 cathode
orn afeerioh)
circuit output
dropout width
scratch
(scratch width)
Fig. 2
Waveform when Dropout is Detected
(Measured on YEDS-1 disc with tape of about 1 mm width stuck on as in Fig. 3)