Sharp MD-MT831H(GL) User manual

MD-MT831H/W
– 1 –
CONTENTS Page
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)
SERVICE MANUAL
SHARP CORPORATION
No. SX963MDMT831H
This document has been published to be used
for after sales service only.
The contents are subject to change without notice.
• In the interests of user-safety the set should be restored to its
original condition and only parts identical to those specified be
used.
MD-MT831H(GL)
MD-MT831W(GL)
Illustration: MD-MT831H
Illustration: MD-MT831W

MD-MT831H/W
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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.
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
outerthan thelead-inposition, theLaser willlightfor severalseconds todetectadisc.Do notlookintothePickup 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 oradjustments,or performance of procedures other thanthose specified herein mayresult
in hazardous radiation exposure.
SAFETY PRECAUTION FOR SERVICE MANUAL

MD-MT831H/W
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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. Leavetheunitcompletelyunpowered for
approximately 30 seconds.
4. Plug the AC adaptor back into the AC
socket and retry the operation.
Ifstrangesounds,smellorsmokecome 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? ●Isan 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. ●Whenthe 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.
Whenthenumberoftracksusedreaches 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 recordthemaximumnumberoftrackson it. If there are scratches on a disc, the unit willautomaticallyavoidrecording in those areas.Therecordingtimewill bereduced. 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 minimumunitofrecording.So,evenifatrack is less than 2 seconds long, it will use about 2 seconds of space on the disc. Therefore, the time actually available for re- cordingmaybelessthantheremainingtime displayed. If there are scratches on discs, those sec- tionswillbeautomaticallyavoided(norecord- 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 soundsmaybeskipped whilst cueing and reviewing. If there are scratches or dust on a MiniDisc,thetracknumbers 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.

MD-MT831H/W
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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. ●Changethestopposition 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.
●Replaceitwithanotherrecorded disc.
Can’t REC
(Can’t R) ●
Recording cannot be performed cor- rectlyduetovibrationorshockintheunit.
●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. ●Nooutput signal comes outfromthe
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. ●Tohaveitrepaired,gotothedistribu-
tor where you purchased the unit.
●Connect the digital cable securely. ●IftheportableCDplayerhasafunction
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.
●Adiscwhichcontains 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.
●Movethe writeprotection knobback
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**) ●Thereisan error inthe 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 > ●Whenthebatteryiscompletelydischarged,
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 BATT” (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 indicatorwillnotcorrectlydisplaytheremain- ing capacity for approximately 20 seconds after the power has been turned on.
●WhentheACadaptorincludedwiththisunit
or a separately available car adaptor is used,thebatteryindicatorwillnotbeshown.
●The number of bars shown in the battery
indicator may increase or decrease, de- pendingontheoperationbeing 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.

MD-MT831H/W
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3
Insert a MiniDisc.
PLAYING A MINIDISC
1
Inserttheearphonesplugfirmlyintotheearphonessocket on the remote control unit.
2
Plug the remote control unit into the socket on the main unit. Push the plug all the way in.
4
■ Play
■ Adjust the Volume
To interrupt playback: Press the button. ●To 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.

MD-MT831H/W
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REMOVING AND REINSTALLING THE MAIN PARTS
Removethemechanismaccordingtothedisassemblingmeth-
ods 1 to 5. (See Page 10.)
Howto remove the spindlemotor(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.
Figure 11-1
Figure 11-2
Figure 11-3
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.
Howtoremovethemagnetichead(SeeFig.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 andremovethesoldering joints(D3)x 2.
Note:
Mount carefully so as not to damage the magnetic head.
(If the gear is damaged, noise is caused.)
Figure 11-4
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.Removethestopwasher(C1)x1pc.,andremovethedrive
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.)
(A2)x3
ø1.4x2.8mm
Spindle Motor
Mechanism Flexible
PWB Solder Joint
(A1)x4
MD Mechanism
(B2)x1
ø1.4x4.5mm
Solder Joint
(B1)x2
MD Mechanism
Lift Motor
(C3)x2
ø1.4x1.2mm
Solder Joint
(C4)x2
MD Mechanism
Sled Motor
(C2)x1
(C1)x1
(E1)x1
ø1.7x3mm
MD Mechanism
Spring
(D1)x1
ø1.4x2.2mm
(D1)x1
ø1.4x1.8mm
(D2)x1
(D1)x2
ø1.4x1.1mm
Solder Joint
(D3)x2
Pickup Unit
Shaft
Magnetic head

MD-MT831H/W
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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 ]
(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).
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
ADJUSTMENT
Test disc
MD adjustment needs two types of disc, namely recording disc (low reflection disc) and playback-only disc (high
reflection disc).
Type Test disc Parts No.
Note: Use the low reflection disc on which music has been recorded.
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
Test Mode
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.
1. AUTO 1 Mode • Perform preliminary automatic adjustment.
• If the combination of mechanism and pickup
PWB has been changed, be sure to start from
AUTO1.
2. AUTO 2 Mode • Perform ATT (attenuator) automatic adjustment.
• Perform continuous playback (error rate display,
jump test)
3. TEST-PLAY Mode • 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.
4. TEST-REC Mode • 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.
5. MANUAL 1 Mode • 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 • 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).
7. ERROR INFORMATION • Error information is displayed.
Mode • Error information is initialized
8. NORMAL Mode • 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.
9. EEPROM Mode • 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)
10. INNER Mode • 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.
EEPROM version
Destination
Microcomputer version

MD-MT831H/W
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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.
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.
• 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.
0032 — 0032 — 0032 — 0032 —
• 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.
1 — 10 — 384 — 1
* 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
Continuous playback (SUBQ address indication) [ S Q ]
|
Continuous playback (C1 error indication) [ C E ]
|
Continuous playback (SUBQ address indication) [ S Q ]
* Recordabl disk
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 ]

MD-MT831H/W
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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. [ R P W _]
• : 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.
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

MD-MT831H/W
– 15 –
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) Performtheoperationtodisplay"EEPROMSETTINGMODECHART",comparetheEEPROMDATALISTwiththe 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)Setthetemperaturereferencevaluebybuttonoperation,andcheckwhetherthetemperaturecodeindicationcorrespondsto"Temperature
Code Identification Table".
[2] Temperature measurement value correction table
Ambient
temperature Temperature
correction
+ 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
Center
temperature Ambient
temperature Temperature
correction Center
temperature
- 9oC ~ +10oC 08h + 0.5oC
+ 3oC ~ +21oC 07h + 12.5oC
+15oC ~ +33oC 06h + 23.6oC
+26oC ~ +43oC 05h + 35.0oC

MD-MT831H/W
– 16 –
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
Item display Set values
Fucus setting
EEPROM DATA LIST (EEPROM version c)
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
Item display Set values
Tracking setting
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
Item display Set values
Spindle setting
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
Item display Set values
Sled setting
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
Item display Set values
BASS setting

MD-MT831H/W
– 17 –
C O K _ 3 8 H
F A T _ C 0 H
T A T _ 3 E H
C A T _ 4 0 H
F A B _ E 0 H
Item display Set values
ADJ. SET setting
T M _ Calculate values
Item display Set values
TEMP setting
C T 0 _ 0 2 H
C T 1 _ 1 5 H
C T 2 _ 1 8 H
C T 3 _ 3 1 H
R C 0 _ C 0 H
R C 1 _ F E H
S Y C _ A 6 H
P W C _ 1 2 H
P W L _ 2 6 H
D R 1 _ 0 9 H
D R 2 _ 4 7 H
I N 1 _ 5 4 H
I N 2 _ 9 D H
I N H _ 6 4 H
D R H _ 7 4 H
P L E _ A 6 H
R C E _ 9 4 H
E L T _ A 0 H
X 2 T _ C 0 H
S D F _ 1 F H
C H V _ 0 C H
S G P _ B 0 H
S 2 P _ 4 0 H
S R T _ 0 A H
S T 0 _ 7 3 H
S T 1 _ 7 3 H
S T 2 _ 7 3 H
S T 3 _ 7 3 H
S T 4 _ 7 A H
S T 5 _ 8 0 H
S T 6 _ 8 0 H
S T 7 _ 8 0 H
S T 8 _ 8 6 H
S T 9 _ 8 D H
S T A _ 8 D H
K C 0 _ 0 6 H
K C 1 _ 0 9 H
K C 2 _ 0 D H
K C 3 _ 0 F H
K C 4 _ 1 1 H
K C 5 _ 1 2 H
K C 6 _ 1 6 H
K C 7 _ 1 7 H
K C 8 _ 1 A H
K C 9 _ 1 F H
K C A _ 1 F H
Item display Set values
Control setting

MD-MT831H/W
– 18 –
: Test Mode STOP
: Pre-auto adjustment menu
: ATT auto adjustment menu
: EEPROM setting menu
: INNER switch position measurement menu
BASS
T E S T
Slide external
periphery move Slide internal
periphery move
Tset Mode Menu
Test Mode Change Chart
A U T O 1
A U T O 2
SKIP UP SKIP DOWN
SKIP DOWN
SKIP UP SKIP DOWN
SKIP UP SKIP DOWN
SKIP UP SKIP DOWN
SKIP UP SKIP DOWN
T R E C
T P L A Y
SKIP UP SKIP DOWN
SKIP UP SKIP DOWN
: Digital input signal monitor menu
E E P R O M
SKIP UP SKIP DOWN
I N N E R
SKIP UP
SKIP UP
SKIP DOWN
SKIP DOWN
SKIP UP
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
* When the [PLAY] button operation is performed in the specific menu, the operation of this
menu is executed.
: Pre-adjustment value check menu
: ATT adjustment value check menu
: Pre-manual adjustment menu
M A N U 1
: ATT manual adjustment menu
M A N U 2
: Error history display menu
E D A T A
N O R M A L

MD-MT831H/W
– 19 –
: ATT Autoadjustment menu
: ATT adjustment error (adjustment value output)
: During ATT autoadjustment
Adjustment error
Normal end
: ATT adjustment normal end (adjustment value output)
: Continuous playback (high reflection)
: Continuous playback (low reflection)
PLAY
PLAY
A U T O 2
ATT Auto Adjustment
A D J . O K
A D J . N G
S Q # # # #
A P # # # #
A T 2
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
* " " represent the adjustment number as follows.
0 0 : Innermost periphery move
0 3 : Pit section tracking ATT setting
0 4 : Pit section focus ATT setting
0 6 : External periphery move (low reflection only)
0 7 : TCRS ATT setting (low reflection only)
0 8 : Groove section tracking ATT setting (low reflection only)
0 9 : Groove section focus ATT setting (low reflection only)
: Preautomatic Adjustment menu
: Preadjustment error (adjustment value output)
: During preadjustment adjustment
Adjustment error
Normal end
: Preadjustment normal end (adjustment value output)
: During ATT automatic adjustment
PLAY
PLAY
A U T O 1
Preautomatic Adjustment
A D J . O K
A D J . N G
A T 2
A T 1
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
* " " represent the adjustment number as follows.
0 0 : Innermost periphery move
0 2 : ABEF offset tentative measurement
0 4 : RF side focus gain coarse adjustment
0 5 : Focus ATT tentative setting
0 6 : RF side bit section tracking gain adjustment
0 7 : COUT level setting for pit section adjustment
0 8 : External periphery move
0 9 : RF side groove section tracking gain adjustment
1 0 : COUT level setting for groove section adjustment
1 1 : RF side TCRS gain adjustment
1 2 : Tracking ATT initial setting
1 3 : RF side focus gain minor adjustment
1 4 : Focus ATT initial setting
1 5 : S gain "High" ABEF offset measurement
1 6 : TCRS offset measurement
1 7 : S gain "Low" ABEF offset measurement

MD-MT831H/W
– 20 –
: Pre-Manual Adjustment menu
: Temperature code display
$ $ : Temperature code
: A signal offset (AINO) tentative measurement
: Measurement value
: B signal offset (BINO) tentative measurement
: Measurement value
: E signal offset (EINO) tentative measurement
: Measurement value
: F signal offset (FINO) tentative measurement
: Measurement value
: Laser ON (Play Power)
: AB MAXO measurement
: Measurement value
: A-ATT (focus) tentative setting
: ATT setting
: B-ATT (focus) tentative setting
: ATT setting
: Pit section adjustment COUT level setting
: COUT level setting
: Groove section adjustment COUT level setting
: COUT level setting
: E-ATT (tracking) initial setting
: ATT setting
: F-ATT (tracking) initial setting
: ATT setting
PLAY
M A N U 1
Pre-Manual Adjustment
T M P $ $
A h
SKIP UP SKIP DOWN
B h
SKIP UP SKIP DOWN
E h
SKIP UP SKIP DOWN
F h
SKIP UP SKIP DOWN
L O N P
SKIP UP SKIP DOWN
A B
SKIP UP SKIP DOWN
S a
SKIP UP SKIP DOWN
S b
SKIP UP SKIP DOWN
e f
SKIP UP SKIP DOWN
P C H
SKIP UP SKIP DOWN
e f
SKIP UP SKIP DOWN
G C H
SKIP UP SKIP DOWN
T C
SKIP UP SKIP DOWN
S E
SKIP UP SKIP DOWN
S F
SKIP UP SKIP DOWN
SKIP UP SKIP DOWN
: Bit section LPFEFO measurement
: Measurement value
: Group section LPFEFO measurement
: Measurement value
: TCRSMIO measurement
: Measurement value
: A-ATT (focus) initial setting
: ATT setting
: B-ATT (focus) initial setting
: ATT setting
: TCRS signal offset (TCRSO) measurement
: Measurement value
a b
S A
SKIP UP SKIP DOWN
S B
SKIP UP SKIP DOWN
T H
SKIP UP SKIP DOWN
: LPFABO measurement
: Measurement value

MD-MT831H/W
– 21 –
: ATT manual adjustment menu
: Temperature code display
$ $ : Temperature code
: Laser ON (Play Power)
: Pit section E-ATT (tracking) setting
: ATT setting
: Pit section F-ATT (tracking) setting
: ATT setting
: High reflection: A-ATT (focus) setting
: Low reflection: A-ATT (focus) setting
: ATT setting
: TCRS ATT setting
: ATT setting
:Groove section E-ATT (tracking) setting
: ATT setting
:Groove section F-ATT (tracking) setting
: ATT setting
: Low reflection: A-ATT (focus) setting
: ATT setting
: Low reflection: B-ATT (focus) setting
: ATT setting
PLAY
M A N U 2
ATT Manual Adjustment
T M P $ $
L O N P
SKIP UP SKIP DOWN
P E
SKIP UP SKIP DOWN
P F
SKIP UP SKIP DOWN
H A
L a
SKIP UP SKIP DOWN
: High reflection: B-ATT (focus) setting
: Low reflection: B-ATT (focus) setting
: ATT setting
H B
L b
SKIP UP SKIP DOWN
G C
SKIP UP SKIP DOWN
G E
SKIP UP SKIP DOWN
G F
SKIP UP SKIP DOWN
L A
SKIP UP SKIP DOWN
L B
SKIP UP SKIP DOWN

MD-MT831H/W
– 22 –
: Continuous playback menu
: Continuous playback (pit section)
: Continuous playback (groove section)
# # # # : Address
: Continuous playback (pit section)
: Continuous playback (groove section)
# # # # : Address
PLAY
T P L A Y
Continuous Playback
S Q # # # #
A P # # # #
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
* In the start address set state the start address changes as follows when the [DISP] button is pressed.
0 0 3 2
H (initial value) 0 3 C 0 H 0 7 0 0 H0 8 A 0 H
A d 0 0 3 2 A d 0 3 C 0
DISP
DISP
A d 0 7 0 0
DISP DISP
A d 0 8 A 0
* In the start address setting state the start address change digit changes when the [MODE] button is pressed.
1st digit (initial value) 2nd digit 3rd digit
A d 0 0 3 2 A d 0 0 3 2
MODE
MODE
A d 0 0 3 2
MODE
* In the continuous playback state the number of jump lines changes as follows shown
the [BASS] button is pressed.
1 (initial value) 10 384
1 T R 1 0 T R
BASS
BASS
3 8 4 T R
BASS
• Continuous playback from current pickup position
: Continuous playback menu
: Start address setting
DISP
T P L A Y
A d 0 0 3 2
PLAY
S Q # # # #
A P # # # #
• Continuous playback from any address
* In the start address set state the value of selection digit changes in the range of "0h to Fh"
when the [SKIP UP/DOWN] button is pressed
* When the [SKIP UP] button is pressed in the continued playback mode, jump of specified
number of lines occurs in the external periphery direction.
If the key is held down jump occurs continuously (100 ms cycle).
* When the [SKIP DOWN] button is pressed in the continuous playback mode, jump of
specified number of lines occurs in the internal periphery direction.
If the key is held down, jump occurs continuously (100 ms cycle).
9 5 0 H

MD-MT831H/W
– 23 –
: Continuous record menu
PLAY
T R E C
Continuous Rrecord
A P # # # #
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
* In the start address set state the start address changes as follows when the [DISP] button is pressed.
• Continuous record from the current pickup position
: Continuous record menu
: Start address setting
: Continuous record
# # # #: Address
: Continuous record
# # # #: Address
PLAY
T R E C
A d 0 0 3 2
PLAY
A P # # # #
• Continuous record playback from any address
A d 0 0 3 2
0 0 3 2 H (initial value) 0 3 C 0 H 0 7 0 0 H 0 8 A 0 H
A d 0 3 c 0
DISP
A d 0 7 0 0
DISP DISP
DISP
A d 0 8 A 0
* In the start address setting state the start address change digit changes when the [MODE] button is pressed.
* In the start address set state the value of selection digit changes in the range of 0h to Fh when
the [SKIP UP/DOWN] button is pressed.
* In the continuous record state and start address set state the record laser power changes in the
range of "0h to Fh" when the [VOL UP/DOWN] button is pressed.
A d 0 0 3 2
1st digit (initial value) 2nd digit 3rd digit
A d 0 0 3 2
MODE
A d 0 0 3 2
MODE
MODE
9 5 0 H
: INNER switch position measurement menu
: Continuous playback (pit section)
# # # # : Address
PLAY
I N N E R
Inner Switch Position Measurement
S Q # # # #
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.

MD-MT831H/W
– 24 –
: Error history display menu
: Error history 0 display
§ § : Error code
: Error history 1 display
§ § : Error code
: Error history 2 display
§ § : Error code
: Error history 3 display
§ § : Error code
: Error history 4 display
§ § : Error code
: Error history 5 display
§ § : Error code
: Error history 6 display
§ § : Error code
: Error history 7 display
§ § : Error code
: Error history 8 display
§ § : Error code
: Error history 9 display
§ § : Error code
PLAY
E D A T A
Error History Display
E 0 § §
E 1 § §
: Error history display menu
: Error history clear
PLAY
E D A T A
C L E A R
SKIP UP SKIP DOWN
E 2 § §
SKIP UP SKIP DOWN
E 3 § §
SKIP UP SKIP DOWN
E 4 § §
SKIP UP SKIP DOWN
E 5 § §
SKIP UP SKIP DOWN
E 6 § §
SKIP UP SKIP DOWN
E 7 § §
SKIP UP SKIP DOWN
E 8 § §
SKIP UP SKIP DOWN
E 9 § §
SKIP UP SKIP DOWN
• Error history clear
• Error history display
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
: TEST mode normal playback menu
: Continuous playback
@@@@@@: Mode and address display
PLAY
N O R M A L
Test Mode Normal Playback
@@@@@@
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
* When the NORMAL mode is canceled, the power is turned off.

MD-MT831H/W
– 25 –
: EEPROM setting menu
: Focus setting menu
: Spin setting menu
: Tracking setting menu
: Sled setting menu
: BASS setting menu
: TEMP setting menu
: Adjustment setting menu
: Digital EQ setting menu
: Control setting menu
PLAY
E E P R O M
EEPROM Setting
F o c u s
S p i n
SKIP UP SKIP DOWN
T r a c k
SKIP UP SKIP DOWN
S l e d
SKIP UP SKIP DOWN
B a s s
SKIP UP SKIP DOWN
T E M P
SKIP UP SKIP DOWN
A D J S E T
SKIP UP SKIP DOWN
D E Q S E T
SKIP UP SKIP DOWN
C T R L
SKIP UP SKIP DOWN
SKIP UP
SKIP DOWN
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
* When the [PLAY] button operation is performed in the specific state, the specific setting menu is set.
: Each setting menu
PLAY
Menu name
Setup operation except for TEMP
Item 1
Item 2
SKIP UP SKIP DOWN
Item 3
SKIP UP SKIP DOWN
* When the [STOP] button is pressed in specific menu, the "TEST MODE STOP" state is set.
* When the [DISP] button operation is performed in the specific state, the menu changes to
"TEMP SETTING menu".
* In the specific state the setting changes in the range of "00h to FFh" when the
[VOL UP/DOWN] button is pressed.
(The upper limit varies depending on the items)
* When the [MODE] button is pressed in each state, the set digit is changed.