Sharp MDMT-831-H, MDMT-831-W Service manual

Illustration: MD-MT831H

MD-MT831H/W

SERVICE MANUAL

No. SX963MDMT831H

MD-MT831H(GL) MD-MT831W(GL)

• In the interests of user-safety the set should be restored to its original condition and only parts identical to those specified be used.

Illustration: MD-MT831W

CONTENTS

SAFETY PRECAUTION FOR SERVICE MANUAL ............................................................................................................... 2

SPECIFICATIONS ................................................................................................................................................................. 3

NAMES OF PARTS ............................................................................................................................................................... 4

OPERATION MANUAL.......................................................................................................................................................... 5

QUICK GUIDE ....................................................................................................................................................................... 8

DISASSEMBLY.................................................................................................................................................................... 10

REMOVING AND REINSTALLING THE MAIN PARTS....................................................................................................... 11

ADJUSTMENT ...................................................................................................................................................................... 12

MD ERROR MESSAGE DISPLAY CONTENT LIST ........................................................................................................... 26

BLOCK DIAGRAM ............................................................................................................................................................... 27

SCHEMATIC DIAGRAM ...................................................................................................................................................... 28

VOLTAGE ............................................................................................................................................................................ 31

WIRING SIDE OF P.W.BOARD........................................................................................................................................... 32

WAVEFORMS OF MD CIRCUIT ......................................................................................................................................... 35

NOTES ON SCHEMATIC DIAGRAM .................................................................................................................................. 36

TYPES OF TRANSISTOR AND DIODE .............................................................................................................................. 36

TROUBLE SHOOTING........................................................................................................................................................ 37

FUNCTION TABLE OF IC.................................................................................................................................................... 40

PARTS GUIDE/EXPLODED VIEW PACKING METHOD (MD-MT831H FOR U.K. ONLY)

Page

SHARP CORPORATION

– 1 –

This document has been published to be used for after sales service only. The contents are subject to change without notice.

MD-MT831H/W

SAFETY PRECAUTION FOR SERVICE MANUAL

Precaution to be taken when replacing and servicing the Laser Pickup.

The AEL (Accessible Emission Level) of Laser Power Output for this model is specified to be lower than Class I Requirements. However, the following precautions must be observed during servicing to protect your eyes against exposure to the laser beam.

(1) When the cabinet has been removed, the power is turned on without a compact disc, and the Pickup is on a position

outer than the lead-in position, the Laser will light for several seconds to detect a disc. Do not look into the Pickup Lens.

(2) The Laser Power Output of the Pickup inside the unit and replacement service parts have already been adjusted prior

to shipping. (3) No adjustment to the Laser Power should be attempted when replacing or servicing the Pickup. (4) Under no circumstances look directly into the Pickup Lens at any time. (5) CAUTION - Use of controls or adjustments, or performance of procedures other than those specified herein may result

in hazardous radiation exposure.

CAUTION

● This Portable MiniDisc Recorder is classified as a CLASS 1 LASER product.

● The CLASS 1 LASER PRODUCT label is located on the bottom.

Use the Portable MiniDisc Recorder only in accordance with the instructions given in

●

this manual and do not attempt to interfere with the interlock switch or make any other adjustment as this may result in exposure to hazardous radiation.

Laser Diode Properties

● Material: GaAIAs

● Wavelength: 785 nm

● Pulse time:

Read mode; 0.8 mW Continuous Write mode; max. 10 mW 0.5S

min. cycle 1.5S

Repetition

(MD-MD831H for U.K.)

LASER KLASSE 1 LUOKAN 1 LASERLAITE KLASS 1 LASERAPPARAT

(MD-MD831H for Europe)(For MD-MD831W)

VAROITUS! LAITTEEN KÄYTTÄMINEN MUULLA KUIN TÄSSÄ KÄYTTÖOHJEESSA MAINITULLA TAVALLA SAATTAA ALTISTAA KÄYTTÄJÄN TURVALLISUUSLUOKAN 1 YLITTÄVÄLLE NÄKYMÄTTÖMÄLLE LASERSÄTEILYLLE.

VARNING - OM APPARATEN ANVÄNDS PÅ ANNAT SÄTT ÄN I DENNA BRUKSANVISNING SPECIFICERAS. KAN ANVÄNDAREN UTSÄTTAS FÖR OSYNLIG LASERSTRÅLNING, SOM ÖVERSKRIDER GRÄNSEN FÖR LASERKLASS 1.

(MD-MD831H for Europe)

Precaution to be taken when replacing and servicing the laser pickup. The following precautions must be observed during servicing to protect your eyes against exposure to the laser.

Warning of possible eye damage when repairing: If the AC adaptor or batteries are connected when the top houising (disc cover) of the unit is removed, and the PLAY key is pressed, the laser will light up during focus access (2-3 seconds). (Fig. 3-1) During the operation, the laser will leak from the opening between the magnetic head and the mechanical chassis (Fig. 3-2). In order to protect your eyes, you must not look at the laser during repair. Before repairing be sure to disconnect the AC adaptor and remove the batteries.

– 2 –

Magnet head

Magnet Head

Laser Beam

Optical Pickup

Main PWB

Spindle motor

Mechanism Chassis

MD-MT831H/W

Optical pickup

Top Cabinet

Figure 3-1 Figure 3-2

FOR A COMPLETE DESCRIPTION OF THE OPERATION OF THIS UNIT, PLEASE REFER TO THE OPERATION MANUAL.

■ General

Power source:

DC 3.6V: Rechargeable Lithium-Ion battery

x 1

DC 5.0V: AC adaptor (AC 220 - 230V, 50/ DC 5.0V: AC adaptor (AC 230 - 240V, 50/ DC 5.0V: AC adaptor (AC 110 - 240V, 50/ DC 3.3V: Battery case (with voltage booster)

DC 4.5V: Separately available car adaptor,

Power consumption:

7 W (AC adaptor) [MD-MT831H]

0.15A (AC adaptor) [MD-MT831W]

Output power:

RMS; 20 mW (10 mW + 10 mW) (0.2% T.H.D.)

Charging time:

Approx. 3 hours (When using the AC adaptor included with the unit)

Battery life:

When using the rechargeable battery (fully charged) included with the unit

Continuous recording:Approx. 9.5 hours Continuous play:Approx. 14.5 hours

When using one, commercially available, high capacity, “AA” size, alkaline battery (The rechargeable battery is in the unit, discharged.)

Continuous recording:Approx. 4.5 hours Continuous play:Approx. 11.5 hours

When using one, commercially available, high capacity, “AA” size, alkaline battery with the rechargeable battery (fully charged)

Continuous recording:Approx. 14 hours Continuous play:Approx. 26 hours

● The continuous recording time is for analogue inputs when the volume level is set to “VOL 0”.

● The continuous play time shows the value when the volume level is set to “VOL 15”.

● The above values are the standard values when the unit is charged and used at an ambient temperature of 20°C (68°F).

● The operating time when using an alkaline battery may be different, depending on the type and manufacturer of the battery, and on the operatin

60 Hz) [MD-MT831H for Europe] 60 Hz) [MD-MT831H for U.K.] 60 Hz) [MD-MT831W] (commercially available, “AA”

size, alkaline battery x 1) AD-CA20X (for cars with a 12-

24V DC negative earth electrical system)

temperature.

SPECIFICATIONS

Input sensitivity:

Recording

level

Reference input

level

Input

impedance

MIC H 0.25 mV 10 k ohms MIC L 2.5 mV 10 k ohms

LINE

100 mV 20 k ohms

Output level:

Earphones

LINE

Specified

output

—

250 mV (-12dB)

Maximum

output level

10 mW +

10 mW

—

impedance

32 ohms

10 k ohms

Dimensions:

Width: 79.4 mm (3-1/8") Height:17.9 mm (11/16") Depth: 81.8 mm (3-3/16")

Weight:

163 g (0.36 lbs.) with rechargeable battery

Input socket:

Line/optical digital, microphone (powered by the main unit)

Output socket:

Earphones (impedance: 32 ohms)/remote control unit

■ MiniDisc Recorder

Type:

Portable MiniDisc recorder

Signal readout:

Non-contact, 3-beam semi-conductor laser pick-up

Audio channels:

Stereo 2 channels/monaural (long-play mode) 1 channel

Frequency response:

20 – 20,000 Hz (± 3 dB)

Rotation speed:

Approx. 400 – 1,350 rpm

Error correction:

ACIRC (Advanced Cross Interleave ReedSolomon Code)

Coding:

ATRAC (Adaptive Transform Acoustic Coding), 24-bit computed type

Recording method:

Magnetic modulation overwrite method

Sampling frequency:

44.1 kHz (32 kHz and 48 kHz signals are converted to 44.1 kHz,

Wow and flutter:

Unmeasurable (less than ±0.001% W. peak)

and then recorded.)

Specifications for this model are subject to change without prior notice

Load

– 3 –

MD-MT831H/W

■ Main unit

1. Monaural Long-Play Mode Indicator

2. Record Indicator

3. Level Meter

4. Fast Play Indicator

5. Repeat Indicator

6. TOC Indicator

7. Battery Indicator

8. Random Indicator

9. Track Number Indicator

10. Character/Time Information Indicator

11. Synchro Recording Indicator

12. Disc Mode Indicator

13. Disc Name Indicator

14. Track Name Indicator

15. Remaining Recording Time Indicator

16. Total Track Number Indicator

17. Record/Track Mark Button

18. Display/Character Select Button

19. Edit/Auto Mark/Time Mark Button

20. Fast Reverse/Recording Level Down/ Name Select Button

21. Fast Forward/Recording Level Up/ Name Select Button

22. Enter/Fast Play/Synchro Button

23. Volume Down/Cursor Button

24. Volume Up/Cursor Button

25. Bass/Fade Time/Delete Button

26. Mode/Fade Button

27. Stop/Power Off Button

28. Play/Pause Button

NAMES OF PARTS

123456

11 12

13 14

15 16

172718 20 21

26252423

7 8

9 10

29. Open Lever

30. Remote Control/Earphones Socket

31. Handstrap Holder

32. Optical/Line Input Socket

33. Hold Switch

34. 5V DC Input Socket

35. Microphone Input Socket

36. Battery Cover

■ Remote control unit

1. Disc Mode Indicator

2. Random Indicator

3. Record Indicator

4. Synchro Recording Indicator

5. Track Number Indicator

6. Total Track Number Indicator

7. Character/Time Information Indicator

8. Battery Indicator

9. Repeat Indicator

10. Attachment Eye

11. Play/Pause/Fast Reverse/ Fast Forward Shuttle Switch

12. Play Mode Button

13. Sound/Track Mark Button

14. Earphones Socket

15. Display/Volume Shuttle Switch

16. Stop/Power Off Button

17. Hold Switch

30 31 32

35 36

3 4

6587

1110 12 13

1514 1716

– 4 –

OPERA TION MANUAL

Caution:

● Whilst you are using the rechargeable

battery and the alkaline battery at the

same time, do not remove either of them.

If you do, when the unit is in the play

mode, playback will stop. When in the

recording mode, the recorded contents

will be erased, and the power may be

disconnected.

● Do not use rechargeable batteries

(nickel-cadmium battery etc.) in the bat-

tery case.

● If the unit is not used for a long period of

time, remove the battery. (Even if the

power is turned off, the battery will drain

slowly but continuously.)

● Remove the battery if it is weak or if the

unit is not in use for long periods to pre-

vent potential damage due to battery

leakage.

● Be sure to hold the plug when removing

it. If you pull on the lead, it may break,

or the unit may malfunction.

● Do not use any car adaptor except for

the separately available AD-CA20X.

● For information about the battery life, see

the battery item in the SPECIFICA-

TIONS.

● This unit should only be used within the

range of 0°C (32°F) and 40°C (104°F).

■ Alkaline battery power with a

rechargeable battery

If you use the battery case and the re-

chargeable battery at the same time, the

MD can play much longer than with only

one source of battery power.

● Use one commercially available alkaline

battery (LR6, “AA” size).

Make sure that a rechargeable battery

is inserted.

● The external battery case should not

be used unless the rechargeable

battery is installed in the main unit.

Insert the battery into the battery case.

(1) Open the case cover.

(2) Insert the battery according to the

polarity marked on the inside of the

battery case. Then, close the case

cover.

Attach the battery case to the main unit.

(1) Match the bumps on the battery case

to the holes in the main unit.

(2) Turn the screw in the direction

marked “LOCK” to secure the bat-

tery case.

■ AC power

Connect the lead from the AC adaptor

to the DC IN 5V socket on the main unit.

Plug the AC adaptor into an AC socket.

Notes:

● When there is thunder or lightning in your

vicinity, unplug the AC adaptor from the

AC socket.

● When power failure occurs whilst play-

ing back using the AC adaptor, discon-

nect the adaptor from the outlet. Other-

wise, playback may start automatically

when the power returns.

● When the unit is not in use for extended

periods, remove the AC adaptor from the

AC socket.

● Never use an AC adaptor other than the

one specified. Otherwise, problems or

serious hazards may be created.

● Do not bend, twist or tie the power lead

or put heavy objects on top of it.

RELEASE LOCK

Press.

Open.

Back of the

MD recorder

POWER SOURCE

■ Rechargeable battery power

This unit can be used with the following power sources: a rechargeable battery, an AC

adaptor, a battery case, and a separately available car adaptor (AD-CA20X).

When the rechargeable battery is used for

the first time or when you want to use it af-

ter a long period of disuse, be sure to charge

it fully.

Open the battery cover.2Insert the rechargeable battery.

● Insert the side with the arrow first.

Close the battery cover.

● Do not fold down the cover before

pulling it up as 1

shows. The cover

may break.

Plug the AC adaptor into the AC socket,

and then insert the plug on the AC adap-

tor lead into the DC IN 5V socket.

● About 4 seconds later, “

” will

flash, and the battery will begin charg-

ing.

● Battery charging will be complete in

3.0 hours. When the charging is com-

plete, “ ” will go out.

Mark

To the DC IN 5V socket

Insert securely

all the way in.

Caution:

● Do not remove the plastic around the

rechargeable battery. Heat generation,

fire and explosion can result.

Notes:

● After charging has been completed, the

AC adaptor may be left connected.

(For example, when charging at night)

● If the rechargeable battery is in the unit,

it will be charged, even whilst operating

the unit. (Float charge)

● Do not force the battery cover open too

far.

● When the AC adaptor plug is inserted

and a MiniDisc has already been in-

serted, playback may start automatically.

In this case, press the

•

■/:OFF button

twice to turn the power off.

AC 110V-240V, 50/60 Hz

(For MD-MT831W)

AC 230V-240V, 50/60 Hz

(MD-MT831H for U.K.)

AC 220V-230V, 50/60 Hz

(MD-MT831H for Europe)

MD-MT831H/W

– 5 –

MD-MT831H/W

Many potential “problems” can be resolved by the owner without calling a service technician.

If something seems to be wrong with this product, check the following before calling your

authorised SHARP dealer or service centre.

■ If trouble occurs

When this product is subjected to strong

external interference (mechanical shock,

excessive static electricity, abnormal sup-

ply voltage due to lightning, etc.) or if it is

operated incorrectly, it may malfunction.

If such a problem occurs, do the following:

1. Unplug the AC adaptor from the AC

socket.

2. Remove the battery.

If trouble occurs with a particular MiniDisc

● Depending on the MiniDisc, sound may skip or stop during playback if there is some-

thing wrong with the stored information. In such a case, try another MiniDisc before

calling for service.

3. Leave the unit completely unpowered for

approximately 30 seconds.

4. Plug the AC adaptor back into the AC

socket and retry the operation.

If strange sounds, smell or smoke come out

of the unit or an object is dropped into the

unit, remove the AC adaptor from the AC

socket immediately and contact an

authorised SHARP service centre.

PROBLEM CAUSE

The unit does not turn

on.

● Is the AC adaptor disconnected?

● Is the battery exhausted?

● Is the unit in the hold mode?

● Has condensation formed inside the unit?

● Is the unit being influenced by mechanical shock or by

static electricity?

● Is the volume set too low?

● Is the remote control unit or the earphones plugged in?

● Are you trying to play a MiniDisc with data on it instead

of a MiniDisc containing music?

● Is the unit in the hold mode?

● Is the battery exhausted?

● Is the remote control unit plug or the earphone plug in-

serted firmly?

● Is the battery exhausted?

● Is the unit being subjected to excessive vibration?

● Has the track number or character information been

written on the disc yet?

● Is the unit in the recording or editing mode?

● Is the MiniDisc protected against accidental erasure?

● Is the unit connected properly to the other equipment?

● Is the AC adaptor unplugged or did a power failure oc-

cur whilst recording or editing?

● Is the unit in the hold mode?

● Is an optical signal being output from the external equip-

ment?

Read the operation manual for the external equipment.

No sound is heard from

the earphones.

When the operation

buttons are pressed, the

unit does not respond.

Some sounds are

skipped.

The MiniDisc cannot be

ejected.

Recording and editing

are impossible.

TROUBLESHOOTING

■ Moisture condensation

In the following cases, condensation

may form inside the unit.

● Shortly after turning on a heater.

● When the unit is placed in a room where

there is excessive steam or moisture.

● When the unit is moved from a cool

place to a warm place.

When the unit has condensation inside,

the disc signals cannot be read, and the

unit may not function properly.

● If this happens, remove the disc.

The condensation should evaporate in

approximately 1 hour. The unit will then

function properly.

When the number of tracks used reaches

the limit, regardless of the remaining re-

cording time, further recording will be

impossible.

(Maximum number of tracks: 255)

If a MiniDisc has been recorded or ed-

ited repeatedly or if a MiniDisc has

scratches on it, it may not be possible to

record the maximum number of tracks on

it.

If there are scratches on a disc, the unit

will automatically avoid recording in those

areas. The recording time will be reduced.

When the remaining recording time of a

disc is displayed, short tracks less than

12 seconds long may not be included in

the total.

For MiniDiscs on which repeated record-

ing and editing operations were per-

formed, the COMBINE function may not

work.

A cluster (about 2 seconds) is normally the

minimum unit of recording. So, even if a track

is less than 2 seconds long, it will use about

2 seconds of space on the disc.

Therefore, the time actually available for re-

cording may be less than the remaining time

displayed.

If there are scratches on discs, those sec-

tions will be automatically avoided (no record-

ing will be placed in those sections). There-

fore, the recording time will be reduced.

For MiniDiscs on which repeated record-

ing and editing were performed, some

sounds may be skipped whilst cueing and

reviewing.

If there are scratches or dust on a

MiniDisc, the track numbers following that

track will be increased by one.

MINIDISC SYSTEM LIMITATIONS

MiniDiscs are recorded using a different system than is used for cassette tapes or DAT

recordings. Therefore, the following conditions may be encountered, depending on how

the disc has been recorded or edited. These are due to system limitations, and should be

considered normal.

Even if the maximum recording

time of a MiniDisc has not been

reached, “DISC FULL” or “TOC

FULL” may be displayed.

Even if the number of tracks and

the recording time have not

reached the limit, “DISC FULL”

may be displayed.

Even if several short tracks are

erased, the remaining recording

time may not show an increase.

Two tracks may not be combined

in editing.

The total of the recorded time and

time remaining on a disc may not

add up to the maximum possible

recording time.

When recorded tracks are played

back using the cue and review op-

erations, some sounds may be

skipped.

A track number can be created in

the middle of a track.

– 6 –

MD-MT831H/W

ERROR MESSAGES

PLAY MD

(PLAY md)

● You tried to record on a playback-

only disc.

● Replace it with a recordable disc.

Error messages RemedyMeaning

BLANK MD

(BLANK)

BATT EMPTY

(Lo BATT)

● The battery is run down. ● Charge the rechargeable battery or

replace the alkaline battery (or use

the AC adaptor for power).

● Nothing is recorded. ● Replace the disc with a recorded disc.

Can’t FADE

Can’t A.F

● The recordable time is shorter than

the fading time

● Record after you check the remain-

ing recording time.

Can’t COPY

(Can’t C)

● No copy can be made because of

the SCMS copyright system.

● Record using the analogue cable.

Can’t EDIT

(Can’t E)

● A track cannot be edited. ● Change the stop position of the track

and then try editing it.

Can’t READ*

(Can’tS)

(Can’T)

(Can’tU)

● The disc is damaged. ● Reload the disc or replace it.

● Replace it with another recorded disc.

Can’t REC

(Can’t R)

●

Recording cannot be performed cor-

rectly due to vibration or shock in the unit.

● Re-record or replace it with another

recordable disc.

Can’t STAMP

● Editing is impossible. ● Check the number of tracks.

Can’t WRITE

(can’tW)

● Cannot save the TOC information

correctly to a MiniDisc.(A large por-

tion of the disc has been damaged.)

● Replace the disc with another re-

cordable disc.

DEFECT

(DEFECT)

● The disc is scratched. ● If the sound you hear is not right, try

recording again.

● Replace the disc with another re-

cordable disc.

DISC FULL

● The disc is out of recording space. ● Replace it with another recordable

disc.

HOLD

(HOLD)

LOCKED

(Can’t LOCK)

NO DISC

Er-MD**

(ErMD*)

NO SIGNAL

(noSIG.)

● Poor connection of the digital cable.

● No output signal comes out from the

external unit to playback.

● The unit is in the hold mode. ● Return the HOLD switch to its origi-

nal position.

● The OPEN lever was moved during

recording or editing.

● Turn off the power and remove the

MiniDisc.

● A disc has not been loaded. ● Load a disc.

● You have come to the conclusion

that the unit is out of order.

● T o have it repaired, go to the distribu-

tor where you purchased the unit.

● Connect the digital cable securely.

● If the portable CD player has a function

to prevent sound skips,deactivate it.

● Playback with the connected unit.

( ) : Error messages seen on the remote control.

* : Number or Symbol.

TEMP OVER

(TEMP!)

TOC FULL

Tr. Protect

? DISC

(? DISC)

● The temperature is too high. ● Turn off the power, and wait for a

while.

● There is no space left for recording

character information (track names,

disc names, etc.).

● Replace it with another recordable

disc.

● A disc which contains data other than

music was played.

● There is an error in the signal from

the disc.

● A disc which contains non-music

data cannot be played.

● Replace it with another recorded

disc.

● The track has been protected from

being erased.

● Edit the track with the device on

which it was recorded.

SORRY

(SORRY)

● Since a track number is currently

being located or written to, the unit

cannot accept your command.

● Wait for a while and try the opera-

tion again.

PROTECTED

● The MD is write protected.

● You tried to record without loading

an MD

● A playback-only MD was loaded

and the REC button was pressed

when the power was off.

● Move the write protection knob back

to its original position.

● Load a recordable MD.

● Replace it with a recordable MD.

Error messages RemedyMeaning

POWER ?

● Improper power is being supplied. ● Use one of the specified power

sources.

TOC FORM**

(T form**)

● There is an error in the recording sig-

nal

● Erase all of the signal errors, and

then try recording again.

( ) : Error messages seen on the remote control.

* : Number or Symbol.

CONVENIENT OPERATION OF THE UNIT

■ Checking the remaining amount

of battery charge

The remaining amount of battery charge

is shown by the battery indicator (

)

during operation.

< How to read the battery indicator >

● When the battery is completely discharged,

the whole battery indicator will flash. Re-

charge the battery or replace the alkaline

battery with a new one.

● When the battery has run completely out,

“BATT EMPTY” (main unit) and “Lo BA TT”

(remote control unit) will appear. Then, the

power will be disconnected automatically.

Notes:

● When using the unit with an alkaline bat-

tery or a rechargeable battery, the battery

indicator will not correctly display the remain-

ing capacity for approximately 20 seconds

after the power has been turned on.

● When the AC adaptor included with this unit

or a separately available car adaptor is

used, the battery indicator will not be shown.

● The number of bars shown in the battery

indicator may increase or decrease, de-

pending on the operation being performed.

This is normal.

● When the rechargeable battery and the al-

kaline battery are used at the same time,

the rechargeable battery is used first, then

the alkaline battery.

Since the battery indicator shows the re-

maining amount of the particular battery

being used, the number of bars will in-

crease when the unit switches to the al-

kaline battery.

Battery indicator

When the battery needs charging, it is

impossible to start recording or editing.

When the battery is

completely charged

Charging is

needed.

– 7 –

MD-MT831H/W

Insert a MiniDisc.

PLA YING A MINIDISC

Insert the earphones plug firmly into the earphones socket

on the remote control unit.

Plug the remote control unit into the socket on the main

unit. Push the plug all the way in.

■ Play

■ Adjust the Volume

To interrupt playback:

Press the button.

● T o resume playback, press the button again.

To stop playback:

Press the

•

■/:OFF button.

To turn off the power:

Press the

•

■/:OFF button whilst in the stop mode.

Volume (0 - 30)

■ Adjust the bass level

BASS 1

BASS 2

BASS 3

BASS OFF

Bass sounds are emphasised slightly

Bass sounds are emphasised more.

Bass sounds are emphasised even

more.

Bass emphasis is cancelled.

SOUND CONTROL

● Playback starts automatically with a

play-back only MiniDisc or a MiniDisc

which is protected against acciden-

tal erasure. (Auto-play function)

■ Insert a MiniDisc

LOADING/UNLOADING A MINIDISC

■ Remove the MiniDisc

■ Remote Control Unit/Earphones

CONNECTION

DIGITAL OUT

AUDIO OUT

■ Analog recording

■ Digital recording

■ Microphone

RIGHT LEFT

Analogue cable included with this unit

Optical digital cable included with this unit

MIC IN

OPEN

REMOTE

OPTICAL

LINE IN

OPTICAL

LINE IN

QUICK GUIDE

– 8 –

MD-MT831H/W

RECORDING

Connect the external equipment.

Insert a recordable MiniDisc.

REC

REC LEVEL

■ Audio

ENTER

SYNC

■ Microphone

ENTER

SYNC

Connect the stereo microphone to the MIC IN socket.

Insert a recordable MiniDisc.

REC

To stop recording:

Press the

•

■/:OFF button.

To turn off the power:

Press the

•

■/:OFF button whilst in the stop mode.

Put the equipment connected to this unit into the playback

stand-by mode.

Begin playback on the

source equipment.

MIC SYNC H

MIC SYNC L

–24dB

–12dB

When a sound, such as a per-

son speaking, is picked up by

the microphone, recording will

begin automatically

● If a silence lasts for 3 sec-

onds or more, the record-

ing will be paused auto-

matically. However , the unit

will not pause for about the

first 10 seconds after re-

cording has started.

Whilst playing sound from the external equipment con-

nected to this unit, press the or button to adjust

the recording level.

0dB–4dB

Start playback on the

equipment connected

to this unit.

Press the or button to adjust the recording level.

0dB–4dB

Press the ENTER/SYNC but-

ton to select the synchro re-

cording level.

REC LEVEL

– 9 –

MD-MT831H/W

DISASSEMBLY

Cares before disassembling

When assembling the machine after disassembling or

repair, observe the following requirements so as to ensure safety and performance.

1. Remove the batteries from the machine, and take out the mini-disc.

2. When assembling after repair, be sure to restore the initial location of wires. Since the screws are small, incorrect fixing may result in malfunction.

3. When repairing, pay utmost attention to static electricity of IC.

(B1)x2 ø1.4x2mm

(A1)x1 ø1.4x2mm

Top Cabinet (A1)x1 ø1.4x2mm

(B1)x2 ø1.4x2mm

(A1)x1 ø1.4x2mm

STEP

REMOVAL

1 Bottom Cabinet 1. Screw ..................... (A1) x5 10-1

2 Top Cabinet 1. Open the Top Cabinet 10-1

3 Center Cabinet A 1. Open the Battery Cover 10-2

4 Main PWB 1. Screw .................... (C1) x1 10-2

5 Mechanism Unit

6 Jack PWB

PROCEDURE

2. Screw ..................... (B1) x6

3. Flexible PWB.......... (B2) x1 10-2

Remove in the arrow direction.

2. Flexible PWB......... (C2) x3

Slacken the main frame in 10-3

the direction of A, then remove it in the direction of B.

Lift the metal fitting in the 10-4

direction of C and remove it in the direction of D.

FIGURE

Battery Cover

Open Lever

Bottom Cabinet

(C1)x1 ø1.7x2.5mm

Main PWB

Pull

(B2)x1

Center Cabinet B

Felt

(A1)x1 ø1.4x2mm

(B1)x2 ø1.4x2mm

Figu re 10-1

Felt

When assembling, attach felt to the flexible PWB not to the connector. If it is slack, it may touch the sheet metal.

Main Frame

Pull

Center Cabinet A

When assembling, put the folded flexible PWB on the connector and attach felt to it. If it is slack, it may touch the sheet metal.

(C2)x1* Flexible PWB for optical pickup

(C2)x1

Pull

(C2)x1

Bracket

Figure 10-4

Main Frame

Jack PWB

Caution:

Carefully handle the main PWB and flexible PWB. After removing the flexible PWB (*1) for the optical pickup from the connector, do not touch directly the front end of flexible PWB with your hand so as to prevent damage of optical pickup by static electricity.

Figure 10-2

Mechanism Unit

Main Frame

Figure 10-3

– 10 –

REMOVING AND REINSTALLING THE MAIN PARTS

Remove the mechanism according to the disassembling methods 1 to 5. (See Page 10.)

MD-MT831H/W

How to remove the spindle motor (See Fig. 11-1.)

1. Remove the solder joint (A1) x 4 of flexible PWB.

2. Remove the screws (A2) x 3 pcs., and remove the spindle motor.

How to remove the lift motor (See Fig. 11-2.)

1. Remove the solder joint (B1) x 2 of Lift motor.

2. Remove the screw (B2) x 1 pc., and remove the lift motor.

Note:

Take care so that the motor gear is not damaged. (If the gear is damaged, noise is caused.)

How to remove the sled motor (See Fig. 11-3.)

1. Remove the stop washer (C1) x 1 pc., and remove the drive

gear (C2) x 1 pc.

2. Remove the screws (C3) x 2 pcs.

3. Remove the solder joints (C4) x 2 of flexible PWB and

remove the sled motor.

Note:

Take care so that the motor gear is not damaged. (If the gear is damaged, noise is caused.)

How to remove the magnetic head (See Fig. 11-4.)

1. Remove the screws (D1) x4 which connects the magnetic

head to the head relay flexible PWB, remove the spring washers (D2) x 1 and remove the soldering joints (D3) x 2.

Note:

Mount carefully so as not to damage the magnetic head. (If the gear is damaged, noise is caused.)

Mechanism Flexible PWB Solder Joint (A1)x4

Solder Joint (B1)x2

Lift Motor

(A2)x3 ø1.4x2.8mm

Spindle Motor

MD Mechanism

Figure 11-1

(B2)x1 ø1.4x4.5mm

MD Mechanism

How to reinstall the optical pickup unit (See Fig. 11-4.)

1. Remove the screw (E1) x 1 pc.

2. Slowly raise the optical pickup.

(D2)x1

Shaft

Pickup Unit

Magnetic head

MD Mechanism

(D1)x1 ø1.4x2.2mm

(D1)x1 ø1.4x1.8mm

Solder Joint (D3)x2

(D1)x2 ø1.4x1.1mm

(E1)x1 ø1.7x3mm

Spring

Figure 11-2

(C1)x1

(C2)x1

Figure 11-3

(C3)x2 ø1.4x1.2mm

Sled Motor

Solder Joint (C4)x2

MD Mechanism

Figure 11-4

– 11 –

MD-MT831H/W

Test disc

ADJUSTMENT

MD adjustment needs two types of disc, namely recording disc (low reflection disc) and playback-only disc (high reflection disc).

Type

1 High reflection disc MMD-110 (TEAC Test MD) 88GMMD-110 2 Low reflection disc MMD-213A (TEAC Test MD) 88GMMD-213A 3 Low reflection disc Recording minidisc UDSKM0001AFZZ

Test disc Parts No.

Note: Use the low reflection disc on which music has been recorded.

Entering the TEST mode

1. Setting at port (in standby state, disc-free state or power nonconnected state)

(1) Set the port as follows. TEST1 : "Low" TEST0 : "High" (2) Press the PLAY button in the standby state (it is allowed to insert the disc or to connect the power supply). (3) Test Mode STOP [ T E S T _ ]

2. Setting by special button operation (in standby state)

Test mode: Perform it with the remote control. (1) Press and hold the "PLAY MODE" button on the remote control and press the "PLAY" button. (2) Release only the "PLAY MODE" button. (3) Press and hold only the "PLAY" button and press the "VOL-" button. (4) When the EL on the remote control turns on, release the "VOL-" button *Since the unit is changed to the setting for production line inspection , be sure to set it to the default setting state in the following default setting procedure before returning it to the user. (5) Normal mode setting initialization (BASS setting, VOL setting, etc.) (6) Indication of microcomputer version for one second [ X X X X X X ]

Destination

Microcomputer version

(7) Whole LCD lighting for 2 seconds (8) Test Mode STOP [ T E S T _ ] *When the PLAY button is pressed during indication (6) and (7), the process proceeds to (8).

EEPROM version

Leaving the TEST mode

(1) Press the STOP button in the TEST mode stop state or version indicating state or whole LCD lighting state. (2) EEPROM rewrite-enable area updating, adjustment error setting . (3) Change to standby state

Shipping setting method

Press and hold the "VOLUME-DOWN" and "PLAY" buttons on the main unit at the same time, supply power from the DC IN plug [INIT], then stop the power supply from the DC IN plug after the "BYE OK" display disappears.

Test Mode

1. AUTO 1 Mode • Perform preliminary automatic adjustment.

2. AUTO 2 Mode

3. TEST-PLAY Mode

4. TEST-REC Mode

5. MANUAL 1 Mode

• If the combination of mechanism and pickup PWB has been changed, be sure to start from

AUTO1.

• Perform ATT (attenuator) automatic adjustment.

• Perform continuous playback (error rate display, jump test)

• Continuous playback from the specified address is performed.

• 1 line, 10 lines or 384 lines manual jump is performed.

• C1 error rate display (pit section), ADIP error rate display (groove section)

• The temperature correction is performed only when servo start is performed, but the posture correction is not performed during continuous playback.

• Continuous record from the specified address is performed.

• Change of record laser output(servo gain is also changed according to laser output).

• The temperature correction is performed only when servo start is performed, but the posture correction is not performed during continuous recording.

• Temperature is displayed. (Updating in real time)

• Seeing the displayed adjustment value, perform

preliminary manual adjustment. (Error rate indication, jump test

6. MANUAL 2 Mode

7. ERROR INFORMATION Mode • Error information is initialized

8. NORMAL Mode

9. EEPROM Mode

10. INNER Mode

• Temperature is displayed. (Updating in real time)

• Seeing the displayed adjustment value perform manfully the preliminary adjustment.

(Error rate indication, jump test)

• Continuous playback is performed

(error rate display, jump test).

• Error information is displayed.

• The mode is changed from the TEST mode to the normal mode without adjustment.

• In the normal mode the internal operation mode, memory capacity, etc. areindicated.

• In the normal mode both temperature correction and posture correction are perfomed.

• Factors of digital servo are changed manually. (Each servo is turned on individually.)

• Cut-off frequency of BASS1, BASS2 and BASS3 is selected manually.

• Temperature detection terminal voltage is measured, and the reference value is set.

• Defaults are selected and set.

• Setting of EEPROM protect area is updated. (In case of protect releasing)

• Determine the position where the INNER switch is turned on. (only high reflection disc).

• The temperature correction is performed only when servo start is performed, but the posture correction is not performed.

– 12 –

MD-MT831H/W

Operation in each TEST mode

1. AUTO1 Mode

• When the STOP button is pressed while the AUTO1 menu appears or during automatic adjustment, the mode changes to the TEST mode stop state. At this time the adjustment value is not output.

• Be sure to adjust, using the specified disc MMD-212.

At this time release the EEPROM (IC402) protection. (Refer to EEPROM write procedure.)

• Adjustment NG; Adjustment item out of range, focus ON failure, and adjustment error

• When the PLAY button is pressed while ADJ. OK is displayed, AUTO2 is executed.

2. AUTO2 Mode

• When the STOP button is pressed while the AUTO2 menu appears or during automatic adjustment, the mode changes to the TEST mode stop state. At this time the adjustment value is not output.

• Adjustment NG; Adjustment item out of range, and adjustment error.

• When the PLAY button is pressed while ADJ. OK is displayed,TEST_PLAY is executed.

3. MANUAL1 Mode

• Adjustment item to be made in AUTO1 mode is performed manually.

• When the VOL UP button is pressed during adjustment, the setting increases, and the new setting is output.

• If the VOL DOWN button is pressed during adjustment, the setting decreases and the new setting is output.

• If the VOL UP/DOWN button is held down, the setting changes continuously with 100 ms cycle.

*In this operation, the setting change is performed for each digit. The digit is changed by pressing the MODE button.

• If the setting is within the allowable range, the RANDOM display lights.

• When the STOP button is pressed during MANUAL1 MENU or measurement or adjustment, the state is changed to the TEST mode stop state.

4. MANUAL2 Mode

• Adjustment item to be made in AUTO2 mode is performed manually.

• When the VOL UP button is pressed during adjustment, the setting increases, and the new setting is output.

• If the VOL DOWN button is pressed during adjustment, the setting decreases and the new setting is output.

• If the VOL UP/DOWN button is held down, the setting changes continuously with 100 ms cycle.

*In this operation, the setting change is performed for each digit. The digit is changed by pressing the MODE button.

• If the setting is within the allowable range, the RANDOM display lights.

• When the STOP button is pressed during MANUAL2 MENU or measurement or adjustment, the state is changed to the TEST mode stop state.

• When the PLAY button is pressed in B-ATT set state, the mode is changed to the continuous playback mode.

• As for operation during continuous playback refer to "TEST-PLAY mode explanation".

5. TEST-PLAY Mode

• When the STOP button is pressed while the TEST-PLAY menu appears, or in TEST-PLAY or continuous playback mode, the mode changes to the TEST mode stop state.

• When the PLAY button is pressed while the TEST-PLAY menu appears,continuous playback is initiated from the current pickup position.

• Whenever the DISP button is pressed in the TEST-PLAY menu, the target address changes as follows.

When the PLAY button is pressed while a target address is displayed, continuous playback is performed after searching that address.

• Each time the MODE button is pressed while the TEST-PLAY mode target address is displayed, the digit which is changed by pressing the SKIP UP/DOWN button is changed as follows.

• When the SKIP UP button is pressed in the TEST-PLAY mode target address is displayed, the digit of address specified by the MODE button is set to +1h. (0 to F)

• When the SKIP DOWN button is pressed in the TEST-PLAY mode target address is displayed, the digit of address specified by the MODE button is set to -1h. (0 to F) * When the SKIP UP/DOWN button is held down, the setting changes continuously, one cycle being 100 ms.

• When the BASS button is pressed in the continuous playback mode, the number of jump lines changes as follows.

* After the number of jump lines is indicated for one second, the address indication is restored. [ T R _ ]

• When the SKIP UP button is pressed in the continuous playback mode, the specified number of lines is jumped in the FWD direction.

• When the SKIP DOWN button is pressed in the continuous playback mode, the specified number of lines is jumped in the REV direction. * When the SKIP UP/DOWN button is held down, jump is repeated every approx. 100 ms.

•Whenever the DISP button is pressed in the continuous playback mode, the indication changes as follows. * Pre-mastered disc

* Recordabl disk

0032 — 03C0 — 0700 — 08A0 — 0950— 0032 —

003

2 — 0032 — 0032 — 0032 —

1 — 10 — 384 — 1

Continuous playback (SUBQ address indication) [ S Q ]

Continuous playback (C1 error indication) [ C E ]

Continuous playback (SUBQ address indication) [ S Q ]

Continuous playback (ADIP address indication) [ A P ]

Continuous playback (C1 error indication) [ C E ]

Continuous playback (ADIP error indication) [ A E ]

Continuous playback (ADIP address indication) [ A P ]

– 13 –

MD-MT831H/W

6. TEST-REC Mode

• When the STOP button is pressed while the TEST-REC menu appears, or in the TEST-REC mode or continuous record mode, the mode changes to the TEST mode stop state.

• When the PLAY button is pressed while the TEST-REC menu appears, the continuous record is initiated from the current pickup position.

• Whenever the DISP button is pressed in the TEST-REC menu, the target address changes as follows.

0032 — 03C0 — 0700 — 08A0 —0950 — 0032 —

When the PLAY button is pressed while a target address is displayed, continuous playback is performed after searching that address.

• Whenever the MODE button is pressed in the TEST-REC mode target address is displayed, the digit which is changed by the SKIP UP/

DOWN button changes as follows.

0032 — 0032 — 0032 — 0032 —

• When the SKIP UP button s pressed in the TEST-REC mode target address is displayed, the digit of address specified by the BASS button is set to +1h.(0 to F)

• When the SKIP DOWN button is pressed in the TEST-REC mode target address is displayed, the digit of address specified by the BASS button is set to -1h. (0 to F)

* When the SKIP UP/DOWN button is held down, the setting changes continuously, one cycle being 100 ms.

• When the VOL UP/DOWN button is pressed in the TEST-REC mode or continuous record mode, the laser record power changes. (Servo gain changes also according to record power.) * After the laser record power is indicated for one second, the address indication is restored.

• : Address

• : Laser power cord

• Operation is disabled if the premastered disc or disc is in miserase-protected state.

7. NORMAL Mode

• When the STOP button is pressed while the NORMAL menu appears, the mode changes to the TEST mode stop state.

• Indication during operation Indication of memory capacity on main unit LCD [ ] + Level meter

: Internal mode : Address (Cluster section) : Address (Sector section)

• Selection of sound volume, BASS, etc. is possible (without indication)

• Recording is also possible.

• If the STOP button is pressed during operation in the NORMAL mode, the NORMAL mode is canceled, and the power is turned off.

[ R P W _ ]

8. Error data display Mode

• Reversing when SKIP DOWN button is pressed

• When the STOP button is pressed while the error data indication menu appears or during error data indication, the mode changes to the TEST mode stop state.

• Error data 0 is the latest error.

• Error which occurred in the TEST mode is also stored in the memory.

• When the DISP button is pressed while the error data indication menu appears, the error data is initialized. [ C L E A R _ ]

: Error Code

•

Explanation of error history code

13h : Adjustment servo retraction excessive retrial 16h : C. IN detection time-over 17h : A, B, E, F, and TCRSO offset measurement value out of tolerable range 21h : Focus retraction completion allowable time-over 23h : Track search completion allowable time-over 32h : P-TOC read failure 42h : U-TOC read failure 44h : U-TOC write data write disabled/read check error 45h : U-TOC write test failure 52h : SD write data write disabled 71h : Pickup position initialization time-over 72h : EEPROM data read check sum error 73h : Record head drive disabled (by EJECT lever) 82h : Power overvoltage detection 91h : Ambient temperature is higher that the allowable temperature.

9. INNER Mode

• when the STOP button is pressed on the INNER menu (SQ______ ), the state is changed to the TEST mode STOP state.

• : Address

– 14 –

MD-MT831H/W

EEPROM (IC402) writing procedure

1. Procedure to replace EEPROM and write initial value of microcomputer in EEPROM

(1) Replace EEPROM. (2) Refer to the latest EEPROM data list. (3) Start the test mode. (Refer to "How to enter the test mode".) (4) Version display

[ V e r . ]

EEPROM version (C ~ Z)

Microcomputer ROM version (5) The whole LCD lights. (6) Test mode stop state.

[ T E S T ]

(7) Press the "BASS" button, and press twice the "SKIP DOWN" button.

[ E E P R O M ]

(8) Perform the operation to display "EEPROM SETTING MODE CHART", compare the EEPROM DATA LIST with the display,

and set according to the EEPROM DATA LIST with the VOL UP or VOL DOWN key.

(9) Set the temperature reference. (Refer to the Temperature Reference Setting Method.)

(10) Set according to the EEPROM DATA LIST.

(11) Press the Stop button.

[ T E S T ] (12) Press the Stop button. (13) After data is written in EEPROM, turn off power .

2. Temperature reference setting method

[1] Measurement, calculation and setting procedure

(1) Set the TEST mode.

• Set TEST 1, 0 = '01', and turn on power (or set PLAY ON in standby state). (2) Start the EEPROM mode 'Temp' menu.

• Key operation in order of BASS, SKIP-DOWN x 2 times, PLAY, PLAY in the test mode STOP state.

• 'TM$$%%' is displayed. ($$= Temperature code, %% = Temperature reference) (3) Once press SKIP-UP, and determine the displayed microcomputer TEMP input AD value.

• 'TPin##' is displayed. (## = TEMP input AD value) (4) At the ambient temperature, determine the temperature corrected value from the temperature measurement value

correction table.

(5) Determine the temperature reference, using the following formula.

• Temperature reference = Microcomputer TEMP input AD value + Temperature corrected value (6) Set the temperature reference value by button operation , and check whether the temperature code indication corresponds to "Temperature

Code Identification Table".

[2] Temperature measurement value correction table

Ambient

temperature

+ 9oC ~ +11oC - 05h + 10.0oC +12oC ~ +14oC - 04h + 12.7oC +15oC ~ +16oC - 03h + 15.4oC +17oC ~ +19oC - 02h + 18.2oC +20oC ~ +22oC - 01h + 20.9oC +23oC ~ +24oC ± 00h + 23.6oC +25oC ~ +27oC + 01h + 26.3oC +28oC ~ +30oC + 02h + 29.0oC +31oC ~ +33oC + 03h + 31.8oC

Temperature

correction

Center

temperature

Ambient

temperature

- 9oC ~ +10oC 08h + 0.5oC

+ 3oC ~ +21oC 07h + 12.5oC +15oC ~ +33oC 06h + 23.6oC +26oC ~ +43oC 05h + 35.0oC

Temperature

correction

Center

temperature

– 15 –

MD-MT831H/W

EEPROM DATA LIST (EEPROM version c)

Fucus setting

Item display

F G 1 _ 2 0 H F G 2 _ 3 1 H F F 0 _ 1 0 H F F 1 _ 7 0 H F F 2 _ E 8 H F f 0 _ 1 0 H F f 1 _ 4 0 H F f 2 _ E 8 H F Z H _ E D H F L n _ 0 A H F L p _ 0 7 H D j G _ 0 D H F S S _ 1 C H F T S _ 1 8 H F S B _ 3 0 H F T B _ 2 8 H F G M _ 6 6 H

Tracking setting

Item display

T G 1 _ 1 8 H T G 2 _ 1 F H T F 0 _ 1 0 H T F 1 _ 7 0 H T F 2 _ E 0 H T f 0 _ 1 0 H T f 1 _ 4 0 H T f 2 _ E 0 H T F S _ 0 0 H T B o _ 2 B H T B t _ 1 4 H T K o _ 2 B H T K t _ 1 2 H T D o _ 6 7 H T D t _ 3 4 H S C o _ 0 0 H S C t _ 1 A H S C m _ 5 3 H C L p _ 2 4 H C L r _ 3 C H J P I _ 0 6 H K 1 0 _ 6 5 H T H P _ 0 2 H T H G _ 0 2 H T O P _ 0 0 H T O G _ F 8 H T 1 P _ 2 0 H

Set values

Spindle setting

Item display

S P G _ 1 4 H S P i _ 4 A H S P m _ 2 9 H S P o _ 1 F H P G M _ E 0 H S P 1 _ 1 0 H S P 2 _ 6 0 H S P 3 _ F 2 H S P 4 _ F 2 H S P 5 _ 1 0 H S p 2 _ 6 0 H S p 5 _ 1 0 H S D 1 _ 7 8 H S D 2 _ 7 F H S P K _ 6 B H M P G _ 4 8 H

Sled setting

Item display

S L G _ 8 0 H S L 2 _ 5 0 H S L M _ 6 A H S K k _ 4 8 H S K t _ 4 A H S K m _ 4 D H W T m _ 2 4 H S B T _ 0 A H S B L _ 4 8 H M V 1 _ 0 0 H M V 2 _ F A H S L V _ 2 8 H S I i _ 2 9 H S I m _ 4 9 H S I o _ 5 9 H S I x _ A A H S L T _ 4 3 H M M V _ 0 0 H S L P _ 4 A H

BASS setting

Item display

B 1 A _ 3 F H B 1 B _ 0 0 H B 1 C _ 0 0 H B 2 A _ 1 F H B 2 B _ 0 0 H B 2 C _ 0 0 H B 3 A _ E 2 H B 3 B _ 0 0 H B 3 C _ 0 0 H

Set values

– 16 –

+ 36 hidden pages

Sharp MDMT-831-H, MDMT-831-W Service manual

Specifications and Main Features

Frequently Asked Questions

User Manual