Samsung MM-28 User manual

MICRO COMPONENT

SYSTEM

MM-28

SERVICEManual

MICRO COMPONENT SYSTEM CONTENTS

1. Precautions

2. Specifications

3. Disassembly and Reassembly

4. Alignment and Adjustments

5. Special Circuit Descriptions

6. Troubleshooting

7. Exploded Views and Parts List

8. Electrical Parts List

9. Block Diagrams

10. PCB Diagrams

11. Wiring Diagram

12. Schematic Diagrams

ELECTRONICS

Printed in Korea

Code no. AH68-20188A

1. Precautions

Follow these safety, servicing and ESD precautions to prevent damage and protect against potential hazards

such as electrical shock and X-rays.

Samsung Electronics 1-1

1-1 Safety Precautions

1. Be sure that all of the built-in protective

devices are replaced.

2. When reinstalling the chassis and its

assemblies, be sure to restore all protective

devices, including control knobs and

compartment covers.

3. Make sure that there are no cabinet

openings through which people--

particularly children--might insert fingers

and contact dangerous voltages. Such

openings include the spacing between the

picture tube and the cabinet mask,

excessively wide cabinet ventilation slots,

and improperly fitted back covers.

4. Design Alteration Warning:

Never alter or add to the mechanical or

electrical design of the unit. Example: Do

not add auxiliary audio or video connec-

tors. Such alterations might create a safety

hazard. Also, any design changes or addi-

tions will void the manufacturer's warran-

ty.

5. Leakage Current Hot Check (Figure 1-1):

Warning: Do not use an 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

Appliances), and Underwriters Laboratories

(UL Publication UL1410, 59.7).

With the unit completely reassembled, plug

the AC line cord directly into a 120V AC

outlet. With the unit's AC switch first in

the ON position and then OFF, measure the

current between a known earth ground

(metal water pipe, etc.) and all exposed

metal parts. Examples: Handle brackets,

metal cabinets, screwheads and control

shafts. The current measured should not

exceed 0.5 milliamp. Reverse the power-

plug prongs in the AC outlet and repeat.

6. Insulation Resistance Cold Check:

(1) With the unit's AC plug disconnected

from the AC source, connect an electrical

jumper across the two AC prongs. (2) Set

the power switch to ON. (3) Measure the

resistance between the shorted AC plug and

any exposed metallic parts. Example:

Screwheads, antenna, control shafts or

handle brackets.

If any of the exposed metallic parts has a

return path to the chassis, the measured

resistance should be between 1 and 5.2

megohms. If there is no return path, the

measured resistance should be "infinite." If

the resistance is outside these limits, a shock

hazard might exist. See Figure 1-2

Device

Under

Test

(Reading should

not be above

0.5mA)

Leakage

Currant

Tester

Earth

Ground

Test all

exposed metal

surfaces

Also test with

plug reversed

(using AC adapter

plug as required)

2-Wire Cord

Antenna

Terminal

Exposed

Metal Part

ohm Ohmmeter

Fig. 1-1 AC Leakage Test

Fig. 1-2 Insulation Resistance Test

Samsung Electronics1-2

1-1 Safety Precautions (Continued)

7. Components, parts and wiring that appear

to have overheated or that are otherwise

damaged should be replaced with parts

that meet the original specifications.

Always determine the cause of damage or

overheating, and correct any potential

hazards

8. Observe the original lead dress, especially

near the following areas: Antenna

wiring, sharp edges, and especially the

AC and high voltage power supplies.

Always inspect for pinched, out-of-place,

or frayed wiring. Do not change the

spacing between components and the

printed circuit board. Check the AC

power cord for damage. Make sure that

no wires or components touch thermally

hot parts.

9. Product Safety Notice:

Some electrical and mechanical parts

have special safety-related characteristics

which might not be obvious from visual

inspection. These safety features and the

protection they give might be lost if the

replacement component differs from the

original--even if the replacement is rated

for higher voltage, wattage, etc.

10 Components that are critical for safety are

indicated in the circuit diagram by

shading, or . Use replacement

components that have the same ratings,

especially for flame resistance and

dielectric strength specifications. A

replacement part that does not have the

same safety characteristics as the original

might create shock, fire or other hazards.

1-2 Servicing Precautions

1. Servicing precautions are printed on the

cabinet. Follow them.

2. Always unplug the unit's AC power cord

from the AC power source before

attempting to: (a) Remove or reinstall any

component or assembly, (b) Disconnect an

electrical plug or connector, (c) Connect a

test component in parallel with an

electrolytic capacitor.

3. Some components are raised above the

printed circuit board for safety. An

insulation tube or tape is sometimes used.

The internal wiring may be clamped to

prevent contact with thermally hot

components. Reinstall all such elements to

their original position.

4. After servicing, always check that the

screws, components and wiring have been

correctly reinstalled. Make sure that the

portion around the serviced part has not

been damaged.

5. Check the insulation between the blades of

the AC plug and accessible conductive parts

(examples: metal panels, input terminals

and earphone jacks).

6. Insulation Checking Procedure: Disconnect

the power cord from the AC source and

turn the power switch ON. Connect an

insulation resistance meter (500V) to the

blades of the AC plug.

The insulation resistance between each

blade of the AC plug and accessible

conductive parts (see above) should be

greater than 1 megohm.

7. Never defeat any of the B+ voltage

interlocks. Do not apply AC power to the

unit (or any of its assemblies) unless all

solid-state heat sinks are correctly installed.

8. Always connect a test instrument's ground

lead to the instrument chassis ground

before connecting the positive lead; always

remove the instrument's ground lead last.

Precautions

Warning1: First read the "Safety Precautions" section of this manual. If some unforeseen circumstance creates a conflict

between the servicing and safety precautions, always follow the safety precautions.

Samsung Electronics 1-3

1-3 Precautions for Electrostatically Sensitive Devices (ESDs)

1-4 Special Precautions and Warning Labels for Laser Products

1. Some semiconductor ("solid state") devices

are easily damaged by static electricity.

Such components are called Electrostatically

Sensitive Devices (ESDs). Examples include

integrated circuits and some field-effect

transistors. The following techniques will

reduce the occurrence of component

damage caused by static electricity.

2. Immediately before handling any

semiconductor components or assemblies,

drain the electrostatic charge from your

body by touching a known earth ground.

Alternatively, wear a discharging

wrist-strap device. (Be sure to remove it

prior to applying power--this is an electric

shock precaution.)

3. After removing an ESD-equipped assembly,

place it on a conductive surface such as

aluminum foil to prevent accumulation of

electrostatic charge.

4. Do not use freon-propelled chemicals.

These can generate electrical charges that

damage ESDs.

5. Use only a grounded-tip soldering iron

when soldering or unsoldering ESDs.

6. Use only an anti-static solder removal

device. Many solder removal devices are

not rated as "anti-static" (these can

accumulate sufficient electrical charge to

damage ESDs).

7. Do not remove a replacement ESD from its

protective package until you are ready to

install it. Most replacement ESDs are

packaged with leads that are electrically

shorted together by conductive foam,

aluminum foil or other conductive

materials.

8. Immediately before removing the protective

material from the leads of a replacement

ESD, touch the protective material to the

chassis or circuit assembly into which the

device will be installed.

9. Minimize body motions when handing

unpackaged replacement ESDs. Motions

such as brushing clothes together, or lifting

a foot from a carpeted floor can generate

enough static electricity to damage an ESD.

Precautions

UL : Manufactured for U.S.A. Market.

CSA : Manufactured for Canadian Market.

EU : Manufactured for European Market.

SCAN : Manufactured for Scandinavian

Market.

This Product Complies with

DHHS Rules 21CFR, Sub

chapter J.At date of Manu-

facture

(UL)

(SCAN)

(EU)

CERTIFIED ONLY TO CANADIAN

ELECTRICAL CODE.

CERTIFIE EN VERTU DU CODE

CANADIAN DE LELETRICITE

SEULEMENT

(CSA)

CLASS 1

LASER PRODUCT

(EU)

Fig. 1-3 Warning Labels (Location: Enclosure Block)

Fig. 1-4 Warning Labels (Location: Disc Clamper, Inner Side of Unit Door or Nearby Unit Chassis )

CAUTION : INVISIBLE LASER RADIATION WHEN OPEN

AND INTERLOCKS DEFEATEO AVOIDEXPOSURE TO BEAM

ADVARSEL:USYNLIG LASERSTRÅLING VED ABNING

NÅR SIKKERHEDSAFBRYDERE ER UDE AF FUNKTION

UNDGA UDSAETTELSE FOR STRALING

VARO:AVATTAESSA JA SUOJALUKITUS OHITETTAESSA

OLET ALTTINA NAKYMATTÖMALLE LASERSATEILYLLE ALA

KATSO SATEESEEN!

VARNING:OSYNLIG LASERSTRÅLNING NAR DENNA DEL

AR OPPNAD OCH SPARREN AR URKOPPLAD BETRAKTA

EJSTRÅLEN!

Samsung Electronics1-4

1-4 Special Precautions and Warning Labels for Laser Products (Continued)

1-4-1 Warnings

1. 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 30 cm from the surface of the objective

lens on the optical pick-up block.

2. Do not attempt to handle the objective lens

when the DISC is not on the tray.

1-4-2 Laser Diode Specifications

Material: GaAs+ GaAlAs

Wavelength: 760-800 nm

Emission Duration: Continuous

Laser Output: 0.2 mw (measured at a

1.6 mm distance from the objective lens

surface on the optical pick-up block.)

1-4-3 Handling the Optical Pick-up

1. Static electricity from clothing or the body

may cause electrostatic breakdown of the

laser diode in the Optical Pickup. Follow

this procedure:

2. Place a conductive sheet on the work bench

(i.e., the black sheet used for wrapping

repair parts.) Note: The surface of the work

bench should be covered by a copper

ground plane, which is grounded.

3. The repair technician must wear a wrist

strap which is grounded to the copper sheet.

4. To remove the Optical Pickup block:

Place the set on the conductive sheet, and

momentarily touch the conductive sheet

with both hands. (While working, do not

allow any electrostatic sources--such as

clothes--to touch the unit.)

5. Ground the "Short Terminal" (located on the

PCB, inside the Pickup Assembly) before

replacing the Pickup. This terminal should

be shorted whenever the Pickup Assembly

is lifted or moved.

6. After replacing the Pickup, reopen the Short

Terminal. See diagrams below:

Precautions

THE UNIT

(1) WRIST-STRAP

FOR GROUNDING

CONDUCTIVE SHEET

short

terminal short terminal short

terminal short

terminal

SOH91VI(LDP) SOH91CI(CAR,walkman) SOH94T4N

(CMS-V10,CMS-V30)

SOH-A1

(CMS-V10,CMS-V30)

2. Product Specfications

Samsung Electronics 2-1

General

Amp

Cassette

Tuner

Compact Disc

(AM)

(option)

Power source

Power consumption

Dimensions (mm)

Power output (Front)

Total harmonic distortion

Frequency range

Signal to noise ratio

Channel separation

Frequency range

Usable sensitivity

Signal to noise ratio

IF rejection ratio

Total harmonic distoration

Separation (Stereo)

Frequency range

Usable sensitivity

Signal to noise ratio

IF rejection ratio

Total harmonic distortion

Frequency range

WOW FLUTTER

Erasing effect

Signal to noise ratio

Total harmonic distortion

Frequency response

Signal to noise ratio

Channel separation

Total harmonic distortion

Audio Output

125Hz ~ 12.5KHz

0.2%

50 dB

40 dB

2.5%

20Hz ~ 20KHz(±1dB)

90 dB(1kHz)

75 dB(1kHz)

0.1%(1kHz)

1V (1kHz 0dB)

Frequency range

Usable sensitivity

Signal to noise ratio

146 ~ 290KHz

60 dB

33 dB

87.5 ~ 108MHz

10 dB

50 dB

60 dB

1.5%

25 dB

522 ~ 1611KHz

50 dB

40 dB

33 dB

15W / Ch

0.5% (1kHz)

50Hz ~ 30kHz

70 dB

40 dB

AC 230V 50Hz(Option)

72W

160(W) x 255(H) x 264(D)

Specifications are subject to change without notice.

TIMER

ON/OFF TIMER/

CLOCK

Remote Control

3. Disassembly and Reassembly

3-1 Cabinet-Top, Cabinet-Rear

1. Remove 6 screws of !and 7 screws of @of its rear part

2. Pull its top part upward vertically as shown in the figure 3-1

Figure 3-1

Samsung Electronics 3-1

Figure 3-2

3-2 Samsung Electronics

3-2 Main PCB

Disassembly and Reassembly

1. Pull out the Main-PCB backward horizontally.

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