SAMSUNG MAX870TC Service Manual

3 CD CHANGER MINI MINI COMPONENT

MAX-870/880/878/888

SERVICE

Manual

3CD CHANGER MINI COMPONENT 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. AH68-20177A

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 connectors. Such alterations might create a safety hazard. Also, any design changes or additions will void the manufacturer's warranty.

5. Leakage Current Hot Check (Figure 1-1): Warning: Do not use an isolation transformer during this test. Use a leakagecurrent 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 powerplug 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 Manufacture

(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

short terminal

SOH91VI(LDP)

short terminal

SOH91CI(CAR,walkman)

CONDUCTIVE SHEET

short terminal

SOH-A1

(CMS-V10,CMS-V30)

SOH94T4N

(CMS-V10,CMS-V30)

2. Product Specfications

Samsung Electronics

2-1

General

Amp

Cassette

Tuner

Compact Disc

MW (AM)

(option)

Power source Power consumption

- MAX-870

- MAX-880

Dimensions (mm) Power output (Front)

- MAX-870

- MAX-880 Total harmonic distortion Frequency response Signal to noise ratio Channel separation Input sensitivity

- Mic

- Aux 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(-5dB)

0.15% 60 dB 40 dB

2.5% 20Hz ~ 20KHz(±1dB)

90 dB(1kHz) 75 dB(1kHz)

0.1% (100Hz)

0.05%(1kHz)

0.2% (10kHz) 1V (1kHz 0dB)

Frequency range Usable sensitivity Signal to noise ratio

146 ~ 290KHz 60 dB 35 dB

87.5 ~ 108MHz 6 dB 62 dB 60 dB

0.3% 35 dB

522 ~ 1611KHz 54 dB 40 dB 30 dB 2%

100W / Ch(6Ω) (THD 10%) 150W / Ch(6Ω) (THD 10%)

0.08% (1kHz) 30Hz ~ 30kHz 75 dB 50 dB (1kHz)

5mV (±3) 400mV (±80)

AC 230V 50HZ (option)

340W 550W 270(W) x 317(H) x 340(D)

Specifications are subject to change without notice.

Remote Control

3. Disassembly and Reassembly

3-1 Cabinet-Top

* If power is connected ;

1. Turn power on and open the CD ,push the Door-CD in the direction of arrow to remove.

2. Remove 7 screws !, @ holding the Cabinet-Top.

Lift the back of the Cabinet-Top and shade it to the rear to remove.

* If power is not connected ;

Remove the Cabinet-Top and Turn the Gear the clockwise using the hand as shown in figure 3-1-1. Open the Door-CD and pull the Tray in the direction of arrow @.

TRAY

Figure 3-1

Samsung Electronics 3-1

Figure 3-1-1

Figure 3-2

3-2 Samsung Electronics

3-2 CD-Mecha, Door-CD

Disassembly and Reassembly

1. Remove 4 screws #, $.

2. Lift the back of the CD-Mecha to remove.

3-3 Cabinet-Rear and Main PCB

1. Remove 9 screws %.

2. Lift the Cabinet-Rear and slide it to the rear by releasing the hook of Cabinet-Bottom.

3. Remove 2 screws ^ and slide the Main PCB to the rear to remove.

1. Remove 2 screws &.

2. Slide it to the front by releasing two hooks on the bottom of Cabinet-Front to remove.

Figure 3-3

Figure 3-4

3-4 Cabinet-Front and Cabinet-Bottom

Samsung Electronics 3-3

Disassembly and Reassembly

Figure 3-5

3-4 Samsung Electronics

Disassembly and Reassembly

3-5 CD Mecha

CD SUB PCB

TRAY DISC ASS'Y

TRAY STOPPER

CD MAIN PCB

HOOK

BASE MAIN

Refer to the next page for timming point

Samsung Electronics 3-5

Disassembly and Reassembly

3-5 CD Mecha Continued

3-5-1 Tray Disassembly

3-5-2 Main Disassembly

3-5-3 CD Main PCB Disassembly

*When removing, take extreme care not to damage the hook.

1. Open the Tray Disc AssÕy by turning the Gear-Load(%) in the direction of open,then remove the Wire-Tray(Q).

2. Remove two Tray-Stopper and tray.

1. Remove the Tray-Roulette(3) from the Tray-Disc AssÕy(4) by releasing the hook.

2. Remove the PCB-Sensor AssÕy(5) from the tray by releasing the hook.

3. Remove the Worm-Motor AssÕy())from the Tray-Disc AssÕy(4).

4. Remove the Cushion-Motor(1) from the Tray.

5. Remove the Gear-Roulette(2) from the Tray-Disc AssÕy(4) by releasing the hook.

1. Remove the Table-Chuck AssÕy(6) from the Base-Main by turning it.

2. Push the Slider-Cam(!)towards right, then lift it up to remove.

3. Remove the Gear-Tray(^) from the Base-Main by releasing the fixed hook.

4. Remove the Gear-Converter(&)from the Base-Main by releasing the fixed hook.

5. Remove the Gear-Cam(%) from the Base-Main by releasing the fixed hook.

6. Remove the Belt(@) from the Pulley-Motor AssÕy(7) & the Gear-Pulley(#).

7. Remove the Gear-Pulley(#) from the Base-Main by releasing the fixed hook.

8. Remove the Gear-Load($).

9. Remove the Gear-Synchro(*).

10. Desolder two soldering points of the CD SUB PCB, then remove it from Base-Main by releasing the hook.

11. Remove the Pulley-Motor AssÕy(7) by releasing the hook.

12. Remove the PCB-SW AssÕy(8) by releasing the hook.

1. Remove the Lever-Lifter(9) from the Base-Main by releasing two hooks.

2. Remove four Rubber-CD(0) from the Lever-Lifter and then remove the Deck-CD(“).

3. Remove the Hook.

4. Remove the CD MAIN PCB with the soldering iron.

Figure 3-6

Figure 3-7

3-6 Samsung Electronics

Disassembly and Reassembly

* Reinstall in reverse order.

* Align the Gear-Cam with the Gear-Tray as

shown ing Figure 3-6, then mount the Tray-Disc.

* When assembling the Tray-Disc,take extreme

care not to engage with Gear-Synchro.

Gear-Cam

Gear-Cam Timming Point

Gear-Cam

Gear-Synchro

Gear-Disc

Insert

Figure 3-8

Samsung Electronics 3-7

3-6 CD Deck

1. Remove the Shaft !.

2. Lift the P/U @.

Note : Take extreme care not to touch the surface of lens.

If there is an alien materials, clean it with swab smeared alcohol.

3. Lift the Center-ring #.

4. Remove the Spring-T/Table $.

5. Remove the Turn-Table (M) %.

6. Remove 2 screws ^ and then remove the Spindle-Motor &.

7. Remove the Cover-Gear * by pushing the hook.

8. Remove the Gear (c) ( by pushing the hook.

9. Lift the Gear(b) ).

10. Remove the Gear(a) 1.

11. Remove 2 screws 2 and the then remove the Feed-Motor 3.

12. Remove the Chassis-Deck (M) 4.

Disassembly and Reassembly

Figure 3-9

3-8 Samsung Electronics

3-6 CD Deck (Option)

Disassembly and Reassembly

1. Remove the Shaft !.

2. Lift the P/U @. Note : Take extreme care not to touch the surface of lens.

If there is an alien materials, clean it with swab smeared alcohol.

3. Lift the Center-Knob #.

4. Remove the Center-ring $.

5. Remove the Spring-T/Table %.

6. Remove the Turn-Table(M) ^.

7. Remove 2 screws & and then remove the Spindle-Motor *.

8. Remove the Cover-Gear ( by pushing the hook.

9. Remove the Gear(c) ) by pushing the hook.

10. Lift the Gear(b) 1.

11. Remove the Gear(a) 2.

12. Remove 2 screws 3 and then remove the Feed-Motor 4.

13. Remove the Chassis-Deck(M) 5.

Samsung Electronics

4. Alignment and Adjustments

4-1 Tuner

4-1

FM THD Adjustment

Output

450kHz

60 dB

Minumum Distortion (0.3% below) (Figure 4-1)

SSG FREQ. Adjustment

point (TL3)

98 MHz

FM DETECTOR COIL

FM Search Level Adjustment

Adjust IVR1 so that “TUNED” of FLT is lighted (Figure 4-2)

Figure4-2 FM Auto Search Level Adjustment

*Adjust FM S.S.G level to 23dB

Figure4-1 IF CENTER and THD Adjustment

SSG FREQ. Adjustment

point

(TSR2)

98 MHz

BEACON SENSITIVITY SEMI-VR(5KΩ)

FM S.S.G

GND

23 dB

FM S.S.G

Output GND

Speaker Terminal

FM Antenna Terminal

Distortion Meter

Input

SET

Input

output

Oscilloscope

FM IN

FM Antenna

SET

5 kΩ

TSR1

AM TUND

TL3

FM T.H.D

TSR2

FM TUND

Alignment and Adjustments

4-2 Samsung Electronics

4-2-1 To Adjust Tape Speed

1) Measuring tape: i) MTT-111 (or equivalent) (Tapes recorded with 3kHz)

ii) MTT-5512 (or equivalent)

2) Connect the cassette deck to the frequency counter

as in figure 4-3.

1) Before the actual adjustment, clean the play/recording head.

2) Measuring tape : i) MTT-114NA(or equivalent 12.5kHz AZIMUTH control) ii) MTT-150(or equivalent : Dolby level 200nwb/m)

3) Dolby NR SW OFF

4) The cassette deck is connections as shown in figure 4-5.

Notes

NOR SPEED Control

OUT (connected to the frequency counter)

Turn JSR5 to left and right

3KHz

6KHz

Turn JSR6 to left and right

Remark

Standard

To Adjust

Pre-Setup

Item

Step

Pre-Setup Condition

Same as above

1) Deck 1:MTT-111

2) Press PLAY SW button

3) Deck 2:Same as above

1) Deck 1:MTT-111

2) Deck 2:MTT-5512

3) Press Hi Speed dubbing SW button

HI SPEED Control

AZIMUTH

TP1 OUT (VTVM is connected to the scope)

1) T urn the control screw to as shown in Figure4-4.

2) Adjust the right

control screw to playback REV . Mode

Max output and same phase (both channels)

After adjustment secure it with REGION LOCK.

150mV

L-CH:T urn JSR1L

to the right and

left R-CH:T urn J SR1R to the right and left

See the diagram for adjustment locations.

Remark

Standard

To Adjust

Pre-Setup

Item

Step

Pre-Setup Condition

Same as above

After putting MTT 114NA into Deck 1

1) Press FWD PLAY button.

2) Press REV PLAY button.

PLAY MTT-150 on Deck 1.

PlayBack out Level

AZIMUTH

TP1 OUT (VTVM is connected to the scope)

1) T urn the control screw to as shown in Figure4-4.

2)Adjust the right

control screw to playback REV . Mode

Max output and same phase (both channels)

After adjustment secure it with REGION LOCK.

150mV

L-CH:T urn JSR2L

to the right and left

R-CH:T urn JSR2R to

the right and left

See the diagram for adjustment locations.

Remark

Standard

To Adjust

Pre-Setup

Item

Step

Pre-Setup Condition

Same as above

After putting MTT 114NA into Deck 2

1)Press FWD PLAY button.

2)Press REV PLAY button.

PLAY MTT-150 on Deck 2.

PlayBack out Level

4-2-2 To Adjust PlayBack Level

@ Adjust Deck 2 Play Level

! Adjust Deck 1 Play Level

TP1

Cassette Deck

output

LINE OUT

Frequency Counter

Figure 4-3

Figure 4-4

LINE OUT

TP1

Recording /Play head

FWD PLAY

REVERSE PLAY

AZIMUTH control screw

Figure 4-5

In Out

Cassette Deck

Oscilloscope

(GND)

VTVM

4-2 Cassette Deck

Alignment and Adjustments

4-3Samsung Electronics

1) Connect the measuring instruments as shown in Figure 4-6.

2) Set the DOLBY NR Switch off.

3) Measuring tape: MTT-5512 (or equivalent: normal recording)

4) The input signals supply 400Hz 400mV into AUX IN of AMP (AUDIO OSC.)

4-2-3 To Adjust Recording Level

Normal electric current for recording

See diagram for adjustment locations

400 mV

6 mV

Connect to TP2 as in Figure4-6 and read VTVM

L-CH : JSR3L to the right and left. R-CH : JSR3R to the right and left

L-CH: JSR4L and R-CH: JSR4R to the right and left

To Adjust

Standard

Remark

Pre-Setup

Item

Step

Pre-Setup Condition

Connect to TP3 as in Figure 4-6 and read the VTVM

Insert MTT-5512 into Deck2, then press REC button.

BIAS Electric current

Figure 4-6

Audio OSC.

Cassette Deck

Oscilloscope

AUX IN

LINE OUT

VTVM

IN OUT

NOTES

JSR6

HI-SPEED

JSR5

NOR SPEED

JSR3L

REC

SIGNAL CURRENT

JSR3R

JSR1R

DECK1

JSR1L

PLAY

JSR2L

JSR2R

DECK2

PLAY

BIAS

JSR4R

CURRENT

JSR4L

Samsung Electronics 5-1

5. Special Circuit Descriptions

5-1 RF Amp Block

5-1-1 RF Amplifier

5-1-2 Focus Error Amp

PD1

PD2

RF-

RFO

RF SUMMINGAMP

10K

58K

IV AMP

10K

58K

IV AMP

32K

160K

32K

164K

FE1

VB> VA>

SW1

FEBIAS

sev-stopb

fe-stopb

fcmpo

sev-stop

X1 X2 X4 X8 X16

<5 Bit Counter>

The two currents from input pins PD1 (A+C) and PD2 (B+D) are converted into voltages through I/V Amp, and they are added to RF summing Amp. The photo diode (A+B+C+D) signal which is I-V changed is outputted by RFO (pin74). At this pin, the eye pattern can be checked.

The output of the focus error amp is the difference between RF I-V AMP(1) output Va and RF I-V AMP(2) output Vb,just is the Photo Diode ((A+C) - (B+D)) signal which is I-V changed. The focus error bias voltage applied to the (+) of focus error amp can be changed by D/A converter as shown in diagram, so that the offset of focus error amp can be adjust automatical. Focus error bias can be adjusted from the range of +100mV ~ -100mV by connectiong the resistor with pin 63 (FEBIAS).

Special Circuit Descriptions

5-2 Samsung Electronics

5-1-3 Tracking Error Amp

5-1-4 Focus OK Circuit

The current signals from the side spot photo diode (E and F) are input to the E and F pin and converted into voltage signals by E I-V and F I-V AMP. The output of tracking error amp is due to the difference between E I-V AMP voltage output. The E-F balance can be adjusted by modifying the gain of E I-V AMP, and the tracking gain(Pin TE1) can be adjusted automatically by micom program.

Extracting the DC part of RFI and RFO and comparing with the basic DC level, if RF Level is more than basic level, the FOK is output. The focus OK circuit generates a timing window of focus on to monitor the focus search status of focus serve.

TGFI

BAL< 4 0 > GAIN< 3 : 0 >

from Digital

TGL

TGH

TE1

LPFT

BALL

To ISTAT,TRCNT

BALH

GAIN-UP/DOWN

75K

220K

110K

56K

27K

13K

16K

7.5K

3.3K

1.5K

IV AMP

WIN COMP

54 55

40K

90K

57K

FOK

VC+0.625V

75 40

Special Circuit Descriptions

Samsung Electronics 5-3

5-1-5 Mirror Circuit

5-1-6 EFM Comparator

After RFI signal is amplified by mirror amp, mirror signal is held in peak and bottom circuit. The following of 100KHZ traverse is possible in peak hold circuit and the loss of track count due to defect is counted in bottom hold circuit. Mirror output beyond 2KHz is. ÒLÓ at track on disc, ÒHÓ at interval between track on disc, ÒHÓ when the defect beyond 1.4ms is detected. The time constant for the mirror hold must be sufficiently large than of the traverse signal

The EFM comparator converts a RF signal into a binary signal As the asymmertry due to variations in disc manufacturing can not be eilminated by thr AC coupling alone, the reference voltage of EFM comparator is controlled utilizing the fact that the generation probability of 1,0 50% each in the binary EFM signals.

38K

96K

17K

1.5K

2.5K

17K

19K

IRF

MIRROR

MCP

Peak and Bottom Hold

40K

100K

20K

85K

19K

RFI

EFM

ASY

Special Circuit Descriptions

5-4 Samsung Electronics

5-1-7 Defect Circuit

5-1-8 APC Circuit

The RFO signal bottom, after being inverted, is held with two time constant of long and short. The short time-constant bottom hold is done for a disc mirror defect more than 0.1msec, the long time-constant bottom hold is done with the mirror level prior to the defect. By differentiating this with a capacitor coupling and shifting the level, both signals are compared to generate the mirror defect detection signal.

As the laser diode has large negative temperature characteristic in its optical output when driven with a constant current on laser diode. Therefore, the output on processing monitor photo diode, must be a controlled current for getting regularly output power, thus the APC (Auto Power Control) circuit is composed.

75K

43K

28K

75K

37.5K

5 4

RFO

DCB

SSTOP/DFCT

DFCT

DCC2DCC1

BOTTOM

HOLD

BOTTOM

HOLD

43.5K LD

5.15K

150K

300K

0.75K

LDON

From Micom

Special Circuit Descriptions

Samsung Electronics 5-5

5-1-9 AGC Stability Circuit

5-1-10 Post Filter

5-1-11 Center Voltage Generation Circuit

The gain is adjusted by AGC Block with the function of maintainning the definite RF peak to peak level, after the operation of RF envelop detection and comparing with reference voltage. RFO level is kept stable in 1Vp-p, and input to EFM Slice.

The adjustment of audio output gain and the integration of possible de-emphasis output are executed by the low pass filter. If the control by MUTE signal from micom exist, and when input signal absent, two channel of right and left is builted in.

The Center Voltage is generated by using resistor dividing voltage.

75 78

IRF CAGC

ARF

EQUALIZEVCA

25K

CH2O

GC2O

GC1O

CH1O

25K

CH2I

GC2I

GC1I

MUTEI (From Micom)

30K

Special Circuit Descriptions

5-6 Samsung Electronics

5-2 Servo Block

5-2-1 Focus Servo Block

5-2-2 Tracking Servo Block

When defect=ÒH (the defect signal is detected), the focus servo loop is muting in case of focus phase compensation. At this time, the focus error signal is outputted through the low pass filter formed by connecting a capacitor(0.1µF) and a built-in 470K½ resistor to the FDFCT pin (pin60). Accordingly, the focus error output is held as the error value just before defect error during defect occuring. The peak frequency of focus loop phase compensation is at about 1.2KHz when the resistor connected to FSET pin(pin6) is 510k½, and it is inversely proportional to the resistor connected to the FSET pin. While the focus search is operating, the FS4 switch is on and then focus error signal is isolated, accordingly the focus search signal is output by FEO pin(pin48). When the FS2 switch is on(focus on), the focus servo loop is on and the focus error signal from FE2 pin(pin58) is outputted through the focus servo loop.

During detection of defect, the tracking error signal is output through the tracking servo loop after through the low pass filter formed by connecting a capacitor(0.1µF) and a built-in 470K½ resistor to the TDFCT pin(pin57) in case of tracking phase compensation. The value of tracking gain up/down can be controlled by TGU and TG2 pin. The peak frequency of tracking loop phase compensation, the dynamic range and offset of op amp can be adjusted by changing the value of resistor connected to FSET pin same as focus loop. In case

of unstable status of actuator after jumping, the ON/OFF of tracking loop is controlled by TM7 switch of break circuit. After 10-track jumping, servo circuit gets out of the liner range and actuator,s tracking is unstable occasionally. Accordingly, unnecessary jumping with many tracking error should be prevented.

26 6 3

FE2

3.6K

20K

40K

10K

50K

PS 43 0X1 0

0X2 1 1X3 0 1X4 1

FS1

FE-

FED

FSCMPO

130K

48K

92K

40K

FS4B

FS2B

DFCTI

FZCI

60K

470K

46K

580K

FS3

470K

FGD

FS3

FDFCT

Focus Phase Compensation

FLB

FSET

FRCH

TE2

TGU

TG2

TDFCT

DFCTI

470K

10K

680K

10K 90K

TED

TE-

66PF

680K

470K

82K

110K

TG1

TM7

FSET

TM4

TM3

TG2

TRACKING PHASE COMPENSATION

Special Circuit Descriptions

Samsung Electronics 5-7

5-2-3 Sled Servo Block

5-2-4 Spindle Servo Block

The 20K½ resistor and 0.33µF capacitor form the 200Hz low pass filter, and the carrier component of spindle servo error signals is eliminated. In CLV-S mode, SMEF becomes ÒLÓ and pin 25 low pass filter fc lowers, strenthening the filter further. The characteristics of high frequency phase compensation in focus tracking servo and the characteristics of cut off frequecny in CLV low pass filter are test by FSET pin.

The moving of pick-up is controlled by tracking servo output through low pass filter. The sled kick voltage is output for track jump operation.

TM6

TM2

SL+

SL-

SLO

43 0X1 0

0X2 1 1X3 0 1X4 1

TM7

22K 22K

15K

220K

100K

50K

Double speed

SPDLO

FSET

SMEF

SPDL-

220K

SMON

SMDP

20K

25 6

Front PCB µ-com VDD(5V)

normal?

UIC1 pin no. 18,46,90

Check the Main PCB RIC2(MC7805),FJ1 Check the Front PCB UD9(1N4002), CN1-1

Main PCB RIC2(MC7805) IN: 12V

Input voltage normal?

Yes

Check the Main PCB; RIC5(MC7812),PBD2 RR11 10Ω(1/2W) Check the Power PCB; Fuse P/T, PW1

Yes

Front PCB

Does UX1(6MHz)

oscillate ?

FRONT PCB PWR-SENS

voltage normal ?

(pin no. 11 ; 5V)

Check the Main PCB RD4,RR19,RC13,RZD3 RC12,RR22,RR20

Yes

Front PCB

When the power is

ON 'H' displays

at pin no. 3 ?(5V)

Yes

Check the Main PCB RQ7(C1008Y),RR9(22K) RQ6(B1566), RR8(680Ω)

Replace µ-com.

Yes

Samsung Electronics 6-1

6. Troubleshooting

6-1 Amplifier

6-1-1 Power Malfunction

6-1-2 No Output

Yes

AQ8L, 8R, 1L, 1R ?

Is Mute selected ?

Remove it with Remocon.

Main PCB AIC1

pin no. 1,8,16,17

B+,B- normal?

Check the B+,B- Power source BPD1, RC7, RC8, RWA1 Check the Power PCB Fuse, P/T, PW1

Yes

Check the Main PCB AIC1, FIC2, FIC1

Yes

Check the Main PCB AQ8L,8R,1L,1R

Headphone Jack short ?

Check Headphone jack soldering condition.

Yes

UIC1(µ-COM) pin 5

Check the Front PCB UIC1 (µ-COM).

Yes

Check the "H"?

Base B+?

6-2 Samsung Electronics

Troubleshooting

+ 64 hidden pages