Samsung RCD-750 User manual

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RADIO CASSETTE RECORDER
CD PLAYER
RCD-750
SE
RVIC
Manual
RADIO
CASSETTE
RECORDER
CD
PLAYER
CONTENTS
Ve PreCaUtION oo osc hal iusiescisiivesesscniierount 1~9
2. SPECIFICATION .......ceceeseesscseeseessessecssesenseesees 10
3. Location Of CONTIOIS.......ccccecsecsccesseeeees 11~12
4. Disassembly instruction...........ccceee 13~14
5. Basic circuit operation... 15~25
6. TrOUDIESNOOTING oo... cecseeesscessessesseceeees 26~30
7. ACJUStMENL.......ccccesceesecseeeesseesseseceeenaees 31~37
8. BIOCK diagram ........cecceseeseessstssceesseeees 38~39
9. Exploded view & parts list ........0..0 40~44
10. Schematic diagram........ccccccseseeeees 45~46
11. PCB Pattern and Marking diagram.....47~49
12. Wiring GiagraM ......ecccccceccecssessscesseeeneeessees 50
13.1C & TR internal diagram... 51~55
14. Electrical parts list.........ccccccceeeeeseees 56~62
15. List of abbreviation .........ccccscccseeeeteeteees 63
@
Design
and
specification
are
subject
to
change
upon
improvement
without
prior
notice.

1. Safety precaution
1-1. Class 1 laser product
This laser disc player is classified as a CLASS 1 laser product.
1-2. Laser warning label
The label shown below may be affixed or not according to country.
(UL) (CSA) (EU)
This Product Complies with CERTIFIED ONLY TO CANADIAN
DHHS Rules 21CFR, Sub ELECTRICAL CODE.
chapter J.At date of Manu-
facture
CERTIFIE EN VERTU DU CODE
CANADIAN DE LELETRICITE
SEULEMENT
CLASS 1
LASER PRODUCT
=
(SCAN)
KATSO SATEESEEN!
VARNING:oSYNLIG LASERSTRALNING NAR DENNA DEL
AR OPPNAD OCH SPARREN AR URKOPPLAD BETRAKTA
Location: Enclosure back.
ear reaar a aie EU) UL _: Manufactured for U.S.A. Market.
ADVARSEL . :
WAR SIKKERHERSAPBRYDERE ER UDE AF FUNKTION CSA _ : Manufactured for Canadian Market.
TF GEORG AMTE EU : Manufactured for European Market.
DIET AET ALA TIGHT TOTAALLE WAGER STERIL ALA SCAN : Manufactured for Scandinavian
Market.
EJSTRALEN!
Location : on the disc clamper or inner side of UNIT door or nearby UNIT chassis.
1-3.Laser beam warning
1-4.
1-5.
ADVERSEL -Usynlig saserstraling ved abning, nar Sikkerhedsafbrydere er ude af funktion.
Undga udsaettelse for straling.
VARNING -Osylig laserstralning nar denna del ar 6ppnad och sparr ar urkopplad. Stralen ar farlig.
VARITUS -Laite sisdltaa laserdiodin, joka lahettaa nakymatdénta silmille vaarallista lasersateilya.
CAUTION -Invisible laser radiation when door is open and interlocks defeate. Avoid exposure to
beam.
Laser diode specification (Optical pick-up)
¢ Material : GaAs+GaAlAs
* Wavelength : 760-800nm
« Emission duration : Continuous
¢ Laser Output : 0.2mW
* This output is the value measured at distance 1.6mm from the objective lens surface on the optical pick-
up block.
* Classification : CLASS 1
Warning for servicing
WARNING: When servicing, do not approach the LASER exit with the eye too closely. In case it is necessary
to confirm LASER beam emission, be sure to observe from a distance of more than 30cm from
the surface of the objective lens on the optical pick-up block.
Nar underhaliningsarbeten utfors, narma dig forsiktigt och se inte pa laserutstralningen pa for
nare hall. If all det ar nodvandigt att betrygga laserstralens utstr6mning. Var saker att kontrollera
detta fran ett avstaand av mer 4n 30cm (11.81 inch.) fraan den objektiva linsens yta pa den
optiska utsandningspunkten.
Nar repareringsarbejdet udfoeres, naerm dig forsigtigt og se ikke pa laserudstralingen paa for
naer haand. “t ilfaeldet at det er noedvaendigt at bestemme laserstralens udstraling. Vaer sikker
pa kontrollere dette fra en afstand af mere end 30cm (11.81 inch.) fra den objektive linses
overflade pa den optiske udsendningspunkt.
Silmia on varottava viemasta liian labeile laser-poistokanavaa huoiion aikana. Jos on
valttamatonta varmistaa Laser-Sateen paast6, pysyttels sita tarkasteltaessa vahintaan 30cm
etaiyydella optisen lukon objecktiivilinssin pinnasta..
VARNING:
ADVARSEL:
VAROITUS:
—1t—

1-1-6.
(1
—
(2
—
(3)
Before returning an instrument to the
customer, always make a safety check of the
entire instrument, including, but not limited
to, the following items:
Be sure that no built-in protective devices are
defective or have been defeated during
servicing. (1) Protective shields are provided
to protect both the technician and the
customer. Correctly replace all missing
protective shields, including any remove for
servicing convenience. (2) When reinstalling
the chassis and/or other assembly in the
cabinet, be sure to put back in place all
protective devices, including, but not limited
to, nonmetallic control knobs, insulating
fishpapers, adjustment and compartment
covers/shields, and isolation resistor/
capacitor networks. Do not operate this
instrument or permit it to be operated
without all protective devices correctly
installed and functioning.
Be sure that there are no cabinet openings
throught which adults or children might be
able to insert their fingers and contact a
hazardous voltage. Such openings include,
but are not limited to, excessively wide
cabinet ventilation slots, and an improperly
fitted and/or incorrectly secured cabinet back
cover.
Leakage Current Hot Check-With the
instrume-nt completely reassembled, plug
the AC line cord directly into a 120V AC
outlet. (Do not use a isolation transformer
during this test.) Use a leakage current tester
or a metering system that complies with
American National Standards institute
(ANSI) C101.1 Leakage Current for App-
liances and Underwriters Laboratories (UL)
1270 (40.7). With the instrument's AC switch
first in the ON positin and then in the OFF
position, measure from a known earth
ground (metal waterpipe, conduit, etc.) to all
exposed metal parts of the instrument
(antennas, handle brackets, metal cabinets,
screwheads, metallic overlays, control
shafts, etc.), especially any exposed metal
parts that offer an electrical return path to the
chassis.
Any current measured must not exceed 0.5
millamp. Reverse the instrument power cord
plug in the outlet and repeat the test.
See Figure 1.
Any measurements not within the limits
specified herein indicate a potential shock
hazard that must be ellminated before
returning the instrument to the customer.
(Reading should
not be above
0.5mA)
Device
Under Leakahe
Currant
Tester
Test all
exposed metal
surfaces
2-Wire Cord
Also test with
plug reversed
(using AC adapter
plug as required)
Earth
Ground
FIG. 1 AC Leakage Test
(4) Insulation Resistance Test Cold Check-(1)
Unplug the power supply cord and connect a
jumper wire between the two prongs of the
plug. (2) Turn on the power switch of the
instrument. (3) Measure the resistance with
an ohmmeter between the jumpered AC
plug and all exposed metallic cabinet parts
on the instrument, such as screwheads,
antenna, control shafts, handle brackets, etc.
When an exposed metallic part has a return
path to the chassis, the reading should be
between 1 and 5.2 megohm. When there is
no return path to the chassis, the reading
must be infinite. If the reading is not within
the limits specified, there is the possibility of
a shock hazard, and the instrument must be
repared and rechecked before it is returned
to the customer.
See Figure 2.

[
1-1-10.
Components,
parts,
and/or
wiring
that
appear
to
have
overheated
or
that
are
otherwise
damaged
should
be
replaced
with
components,
parts
and/or
wiring
that
meet
Original
specifications.
Additionally,
determine
the
cause
of
overheating
and/or
damage
and,
if
necessary,
take
corrective
Antenna
Terminal
age
action
to
remove
any
potential
safety
elal
Pa
hazard.
Ohmmeter
1-1-11.
Product
Safety
Notice-Some
electrical
and
mechanical
parts
have
special
safety-related
characteristics
which
are
often
not
evident
ee
from
visual
inspection,
nor
can
the
protection
they
give
necessarily
be
obtained
by
replacing
them
with
components
rated
FIG. 2 Insulation Resistance Test
1-1-7.
Read
and
comply
with
all
caution
and
safety-
for
higher
voltage,
wattage,
etc.
Parts
that
related
notes
non
or
inside
the
cabinet,
or
on
hae
special
safety
characteristics
are
the
chassis.
identified
by
shading,
an
(x)
ora(
)
on
sc-
hematisc
and
parts
lists.
Use
of
a
substitute
1-1-8.
Design
Afteration
Warning-Do
not
alter
or
add
replacement
that
does
not
have
the
same
to
the
mechanical
or
electrical
design
of
this
safety
characteristics
as
the
recommended
instrument.
Design
alterations
and
additions,
replacement
part
might
created
shock,
fire
including
but
not
limited
to,
circuit
and/or
other
hazards.
Product
safety
is
under
modifications
and
the
addition
of
items
such
review
continuously
and
new
instructions
as
auxiliary
audio
output
connections,
might
are
issued
whenever
appropriate.
alter
the
safety
characteristics
of
this
instrument
and
create
a
hazard
to
the
user.
Any
design
alterations
or
additions
will
make
you,
the
servicer,
responsible
for
personal
injury
or
property
damage
resulting
therefrom.
1-1-9.
Observe
original
lead
dress.
Take
extra
care
to
assure
correct
lead
dress
in
the
following
areas:
(1)
near
sharp
edges,
(2)
near
thermally
hot
parts
(be
sure
that
leads
and
components
do
not
touch
thermally
hot
parts),
(3)
the
AC
supply,
(4)
high
voltage,
and
(5)
antenna
wiring.
Always
inspect
in
all
areas
for
pinched,
out-of-place,
or
frayed
wiring.
Do
not
change
spacing
between
a
component
and
the
printed-circuit
board.
Check
the
AC
power
cord
for
damage.

2. Servicing notes
2-1. Before servicing the unit
Be sure to observe the safety notes attached on label,
chassis, cabinet top, cabinet bottom and printed
circuit board.
2-1-1. Caution on laser beammalfunction
Do not try to access objective lens, when DISC is not
on the tray.
When pick-up mechanism replacement is required,
be sure to turn power off.
2-1-2. When handling parts
Tube, tape or insulating parts are used for sepa-ration
or insulation purposes. Especially parts which
generate excessive heat are kept away from PCB or
any other sensitive parts. Therefore, when replacing
parts, be sure to replace them in their original
position.
2-1-3. When fixing wires
Wires should be fixed in such a way with cable-tie so
they won't move.
When finished servicing, be sure to leave unit in it’s
original configuration.
2-1-4. Use specified parts only
The safety specification built into the electronics of
this unit require that you use specified parts only. Do
not use any other replacements. Using other parts
can result in electrical and fire hazard.
2-1-5. After servicing is complete
After servicing is complete, check if there are any
missing parts or that wires are properly fixed and any
place
where
over
heating
or
shock
is
likely
to
occur,
can be found.
short terminal
SOH91Cl(CAR, walkman)
2-1-6. Handling the optical pick-up
*
The
laser
diode
in
the
optical
pick
up
may
suffer
electrostatic
breakdown
because
of
potential
static
electricity
from
clothing
and
your
body.
The following method is recommended.
(1)
Place
a
conductive
sheet
on
the
work
bench
(The
black
sheet
used
for
wrapping
repair
parts.)
(2)
Place
the
set
on
the
conductive
sheet
so
that
the
chassis
is
grounded
to
the
sheet.
(3) Place your hands on the conductive sheet (This
gives them the same ground as the sheet).
(4) Remove the optical pick up block.
(5) Perform work on top of the conductive sheet. Be
careful not to let your clothes or any other static
sources to touch the unit.
* Be sure to put on a wrist strap grounded to the
sheet.
* Be sure to lay a conductive sheet made of copper
etc. which is grounded to the table.
THE UNIT
(1) WRIST-STRAP
FOR GROUNDING
(6) Short the short terminal on the PCB, which is
inside
the
Pick-Up
ASS'Y,
before
replacing
the
Pick-Up.
(The short terminal is shorted when the Pick-Up
Ass'y is being lifted or moved.)
(7) After replacing the Pick-up, open the short
terminal on the PCB.
terminal
SOH94T4N
(CMS-V10,CMS-V30)
terminal
SOH-A1
(CMS-V10,CMS-V30)

2-2. Servicing Precautions
CAUTION: Before servicing Instruments covered by
this service manual and its supplements, read and
follow the Safety Precautions section of this manual.
Note: If unforseen circument create conflict between
the following servicing precautions and any of the
safety precautions, always follow the safety
precautions.
Remember: Safety First.
2-2-1. General Servicing Precautions
(1) a. Always unplug the instrument's AC power cord
from the AC power source before (1) removing
or reinstalling any component, circuit board,
module or any other instrument assembly, (2)
disconnecting any instrument electrical plug or
other electrical connection, (3) connecting a test
substitute in parallel with an electrolytic
capacitor in the instrument.
b. Do not defeat any plug/socket B+ voltage
interlocks with which instruments covered by
this service manual might be equipped.
c. Do not apply AC power to this instrument
and/or any of its electrical assemblies unless all
solid-state device heat sinks are correctly
installed.
d. Always connect a test instrument's ground lead
to the instrument chassis ground before
connecting the test instrument positive lead.
Always remove the test instrument ground
lead last.
Note: Refer to the Safety Precautions section
ground lead last.
(2) The service precautions are indicated or printed
on the cabinet, chassis or components. When
servicing, follow the printed or indicated service
precautions and service materials.
(3
—
The components used in the unit have a specified
flame resistance and dielectric strength. When
replacing components, use components which
have the same ratings. Components identified by
shading, by (x) or by ( A\ ) in the circuit diagram
are important for safety or for the characteristics
of the unit. Always replace them with the exact
replacement components.
(4) An insulation tube or tape is sometimes used and
some components are raised above the printed
wiling board for safety. The internal wiring is
sometimes clamped to prevent contact with
heating components. Install such elements as
they were.
(5) After servicing, always check that the removed
screws, corponents, and wiring have been
installed correctly and that the portion around the
serviced part has not been damaged and so on.
Further, check the insulation between the blades
of the attachment plug and accessible conductive
parts.
2-2-2. Insulation Checking Procedure
Disconnect the attachment plug from the AC outlet
and turn the power ON. Connect the insulation
resistance meter (500V) to the blades of the
attachment plug. The insulation resistance between
each blade of the attachment plug and accessible
conductive parts (see note) should be more than 1
Megohm.
Note: Accesible conductive parts include metal
panels, input terminals, earphone jacks, etc.

2-3. ESD, Precautions (6) Do not remove a replacement ESD device from its
Electrostatically SensitiveDevices (ESD)
Some semiconductor (solid state) devices can be
damaged easily by static electricity.
Such components commonly are called Electro-
protective package until immediately before your
are ready to install it. (Most replacement ESD
devices are packaged with leads electrically
shorted together by conductive foam, aluminum
foil or comparable conductive materials).
statically Sensitive Devices (ESD). Examples of typical (7) Immediately before removing the protective
ESD devices are integrated circuits and some field-
effect transistors and semiconductor chip com-
ponents. The following techniques should be used to
help reduce the incidence of component damage
caused by static electricity.
(1) Immediately before handling any semiconductor
component or semiconductor-equipped
assembly, drain off any electrostatic aharge on
your body by touching a known earth ground. (8
Alternatively, obtain and wear a commercially
available discharging wrist strap device, which
should be removed for potential shock reasons
prior to applying power to the unit under test.
(2) After removing an electrical assembly equipped
with ESD devices, place the assembly on a con-
ductive surface such as aluminum foil, to prevent
electrostatic charge buildup or exposure of the
assembly.
(3) Use only a grounded-tip soldering iron to solder
or unsolder ESD devices.
(4
—
Use only an anti-static solder removal device.
Some solder removal devices not classified as
“anti-static” can generate electrical charges
sufficient to damage ESD devices.
(5) Do not use freon-propelled chemicals. These can
generate electrical charges sufficient to damge
ESD devices.
—
materials from the leads of a replacement ESD
device, touch the protective material to the
chassis or circuit assembly into which the device
will be installed.
CAUTION: Be sure no power is applied to the
chassis or circuit, and observe all other safety
precautions.
Minimize bodily motions when handling unpack-
aged replacement ESD devices. (Otherwise
harmless motion such as the brushing together
of your clothes fabric or the lifting of your foot
from a carpeted floor can generate static
electricity sufficient to damage an ESD device).

3.
Chip
replacement
3-1.
Precaution
for
the
Chip
Replacement
(1)Do
not
touch
the
part
body
directly
with
the
soldering
iron.
ICS,
especially
TSOP,
are
easily
damaged
by
heat.
(2)
Use
care
regarding
soldering
iron
tip
and
avoid
rapidly
heating
parts.
Some
parts
can
be
damaged
by
sudden
heating.
Preheat
the
part
at
about
100°C
for
several
minutes
before
installing
it.
(3)
Use
soldering
tip
temperature
of
about
240°C
or
larger
parts,
use
a
slightly
higher
temperature
(about
280°C).
(4)
The
thin
(0.3mm)
solder
for
miniature
parts
does
not
contain
adequate
flux.
Supplementary
flux
is
thus
needed
in
most
cases.
The
NoteMaster
486S/25N
series
systems
are
manufactured
using
flux
which
can
be
cleaned
by
water
in
the
factory.
When
your
replace
the
part
or
troubleshooting,
use
proper
flux
and
solder
which
can
be
cleaned
by
water.
Soldering
area
will
corrode,
if
proper
flux
and
solder
are
not
used
in
replace.
And
it
may
cause
a
fatal
error
to
the
system.
(5)
Use
care
not
to
damage
the
circuit
pattern,
especially
when
removing.
(6) Because of the many pins, cleanliness of the
pattern
is
extremely
important
after
removing
the IC.
(7) Use care to avoid solder bridges. Remove any
that occurs.
(8) Position the part carefully. This will also affect the
soldering
operation.
Be
very
precise
in
positioning
the
IC.
Soldering
opposite
pins
first
holds
the
IC
in
place
and
makes
soldering
the
other pins easier.
(9) Do not reuse removed parts.
(10)
Check
for
solder
joints,
especially
miniature
parts
with
small
lead.
(11)
A
defective
trimming
resistor
cannot
be
adjusted
externally.
Replace
with
an
ordinary
variable
resistor.
(12)
It
is
important
to
inspect
the
work
with
a
magnifier.
Check
after
installing
(cold
solder
Joints,
etc).
3-2.
Tools
for
the
Chip
Replacement
The
tools
for
the
chip
replacement
are
as
follows:
(1) Thin tip type soldering iron
(2) Small flat-blade tip type soldering iron
(3) Special desoldering tip iron
(4) Airblower unit
(5) Flat Package Pick-up
(6) Flux can be cleaned by water
(7)
0.3mm
thin
solder
can
be
cleaned
by
water
(8)
Desoldering
wire
(9) Tweezers
3-3.
Chip
Resistors
and
Chip
Capacitors
3-3-1.
Kind
jof
the
Part
The
kind
of
chip
resistors
and
chip
capacitors
as
follows
(1) Thick Film Chip Resistors
(2) Carbon Film Chip Resistors
(3) Metal Film Chip Resistors
(4) Chip Ceramic Capacitors
(5) Chip Trimming Resistors
3-3-2. Removing the Part
The
kind
of
chip
resistors
and
chip
capacitors
as
follows
(1) Using two soldering irons:
© Use thin tip soldering irons.
@
Use
soldering
tip
temperature
of
about
280°C
@
Simultaneously
heat
both
ends
of
the
part.
@
While
heating,
grasp
the
part
with
the
tips
of
the
soldering
irons
and
remove
it.
©)
Use
desoldering
wire
to
completely
remove
the
old
solder
from
the
part
location
of
the
board.
©
A
clean
pattern
for
installing
the
new
part
is
very
important.
FIG, 4
3-3-3. Installing the Part
(1)
Clean
the
area
where
the
new
part
is
to
be
mounted.
(2) Apply flux.
(3) Set part correctly into position, prevent it from
shifting.
(4)
Bring
the
soldering
iron
tip
close
to
the
part
contact
without
actually
touching
it.
Melt
thin
(0.3mm)
solder
between
the
tip
and
part
so
that
it
flows
into
the
part
contact.
(5) Check work quality with a magnifier.
mtn

3-4. Chip Tantalum Capacitors and Chip
Filters
3-4-1. Kind of the Part
The kind of chip tantalum capacitors and chip filters
are as follows:
(1) Chip Inductors
(2) Chip Tantalum Capacitors
(3) Chip Tantalum Electrolytic Capacitors
(4) Chip Aluminum Electrolytic Capacitors
(5) Chip Transformers
(6) Chip Filters
3-4-2. Removing the Part
(1) Using special desoldering iron:
Select soldering tip according to part size.
@) Bring the tip into contact with the soldered points.
@) When the solder melts, remove the part.
@Remove the old solder with desoldering wire.
(1) Using two soldering irons:
CD Use small flat-blade tips.
@) Heat both ends of the part simultaneously.
@) When the solder melts, grasp and remove the part
with the soldering iron tips.
@ Remove the old solder with desoldering wire.
gm
pow
Ww
3-4-3. Installing the Part
(1) Clean the area where the new part is to be
mounted.
(2) Apply flux
(3) In part correctly into position, prevent it from
shifting.
(4) Use sharp soldering iron tip. Bring close to the
part contact without actually touching it. Melt thin
solder between the tip and part so that if flows
into the part contact.
(5) Check work quality with a magnifier.
FIG. 5
3-5. Chip VRs, Chip Trimmer Capacitors,
Diodes and Tr.
3-5-1. Kind of the Part
The kind of the part is as follows:
(1) Chip VRs
(2) Chip Trimmer Capacitors
(3) Diode
(4) Transistors
3-5-2. Removing the Part
(1) Using two soldering irons:
@ Use small flat-blade tips.
@) Heat the leads of the part simultaneously.
@ When the solder melts, grasp and remove the part
with the soldering iron tips.
@ Remove the old solder with desoldering wire.
3-5-3. Installing the Part
, >
(@ es
FIG. 6
(1) Clean the area where the new part is to be
mounted.
(2) Apply flux
(3) Set part correctly into position, prevent it from
shifting.
(4) Use sharp soldering iron tip. Bring close to the
part contact without actually touching it. Melt thin
solder between the tip and part so that it flows
into the part contact.
3-6. Chip ICs
3-6-1. The kind of the Chip ICs
The kind of the chip ICs are as follows:
(1) SOP (Small Outline Package) IC
(2) SSOP (Shrink Small! Outline Package) IC
(3) VSOP (Very Smail Outline Package) IC
(4) OFP (Quad Flat Package) IC
(5) VOFP (Very Quad Flat Package) IC
(6) PLCC (Plastic Leaded Chip Carrier) IC
(7) TSOP (Thin Small Outline Package) IC

3-6-2. Removing the Part
(1) Using special desoldering iron:
@ Select the tip according to the size and shape of
the IC.
@) Thin" the tip with a small amount of the IC leads.
@) Set the tip squarely over the IC leads.
@) When the solder melts, carefully twist the iron.
©) Raise and remove the IC.
(2) Using shaped airblower unit:
( Select the correct nozzle.
@) Select the temperature and airblow (suggested:
temperature: 7, airblow: 4)
@ Engage the IC removing tool.
@ Use the airblow to preheat the IC for about 5
seconds, then heat with the nozzle until the IC
remover lifts the part from the board.
'
SE
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-~4-
FIG. 7
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LI PRY
3-6-3. Installing the Part
(1) Use desoldering wire to remove the previous
older.
(2) Clean the location.
(3) Apply flux.
(4) Position the IC and solder two pins at opposite
sides.
(5) Use a sharp tipped soldering iron and carefully
solder each pin. (After graining experience, a
thicke tip can be used for better work efficiency.)
(6) Remove any solder bridges with desoldering wire.
(7) Inspect the work with a magnifier.