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– 9 –

$

P1.

To read the signals recorded on the disc, the laser beam emitted by the laser diode (LD) strikes the disc and is reflected back and
detected by the photodetector (PD).

T

 For a pre-mastered disc, similar to a CD, the signals are recorded as pits on the surface of the disc, and the signals are

detected by the amount of light reflected when the laser beams strikes the pits.

T

 For a recordable disc, the signals are recorded by magnetizing the magnetic film on the surface of the disc and there is no

variation in the amount of light that is reflected, so the signals are detected using the shifting of  the polarization of the
reflected light due to the Kerr effect*

.

P2.

The detected signals are input to pins 38 and 39 of the RF IC (IC1), where they are amplified and then output from pin 32.

T

 By observing the input signals (between pins 38 and 39) and the output signals (pin 32) on an oscilloscope, it is  possible to

check the eye pattern.

P3.

Error correction of the amplified signals is performed by the MD LSI (IC3: MN66616) using EFM demodulation and ACIRC*

 and

the signals are  stored in the DRAM (IC72: MNV4400).  At this time, the cycle of the signals is adjusted by the LSI's clock in order
to eliminate any jitter that might result from irregular revolution of the disc.

P4.

The signals are sequentially taken from the DRAM (IC72) and sent back to the MD LSI (IC3), where they are ATRAC*

-decoded

and then output from pin 64.

All of the above steps 1 through 4 are processed on the MD servo PCB, and all of the signals are digital.
P5.

The digital signals output from the MD LSI are input to pin 13 of the A/D-D/A converter (IC601: AK4520) via the interface IC
(IC401: TC74HCT7007; input: pin 3; output: pin 4), where they are converted to analog signals and then output from pins 26 (left
channel) and 27 (right channel).

P6.

The analog-converted signals are output to LINE OUT via the buffer amp (IC711: BA4560; input:  pins 5 (left channel) and 3 (right
channel); output:  pins 7 (left channel) and 1 (right channel)).  At the same time, they are also output to the headphone amp
(IC801: M5218; input:  pins 5 (left channel) and 3 (right channel); output:  pins 7 (left channel) and 1 (right channel)).

T

 The MD servo PCB operates at Vcc = 3.3 V, and the main PCB operates at Vcc = 5 V.  For that reason, the exchange of

signals between the two PCBs is performed via an interface IC (during playback: IC401 (TC74HCT7007); during recording:
IC402 (TC74HCT4050)).

T

 The exchange of signals between the DRAM and the MD LSI is performed using four data lines (pins 1, 2, 24, and 25 of the

DRAM and pins 43, 44, 45, and 46 of the MD LSI).

R1.

The analog signals input from LINE IN pass through the REC LEVEL VR and are input to pins 5 (left channel) and 3 (right
channel) of the A/D-D/Aconverter (IC601) via the buffer amp (IC751: BA4560; input: pins 5 (left channel) and 3 (right channel);
output: pins 7 (left channel) and 1 (right channel)).

R2.

The analog signals input to the A/D-D/A converter (IC601) are converted to digital signals with a sampling frequency of fs = 44.1
kHz and then output from pin 14 to pin 65 of the MD LSI (IC3) via the interface IC (IC402: TC74HCT4050 ; input: pin 3; output: pin
4).

R3.

The signals input from OPTICAL IN are input to pins 70 and 71 of the MD LSI (IC3) via the interface IC (IC401; input: pin 9; output:
pin 8).

R4.

The signals input to pins 70 and 71 of the MD LSI (IC3) are converted to a sampling frequency of fs = 44.1 kHz by an fs converter
inside the LSI.  If the signals are already fs = 44.1 kHz, they bypass the fs converter.

R5.

The signals converted to fs = 44.1 kHz or the signals input to pin 65 are ATRAC-encoded and stored in the DRAM (IC72).

R6.

The signals are sequentially taken from the DRAM (IC72) and sent theback to the MD LSI (IC3), where they are ACIRC-processed
and EFM-modulated and then output from pin 73 to the magnetic head.

R7.

The magnetic disc records the signals onto the disc by magnetizing the magnetic film on the surface of the disc.  During recording
the laser diode emits its laser beam in order to raise the temperature to the Curie temperature*

 that is required to magnetize the

magnetic film.  For this reason, the optical power of the laser diode is higher during recording than during playback.

T

 Although the disc revolves at a speed fast enough to write the signals without compression, the recording signals are

compressed in order to reduce the data volume.  As a result, the signals are written intermittently rather than continuously
(the recording signals are intermittently sent to the magnetic head).

C1.

Performs the necessary controls for each operation during playback and recording and for writing of the UTOC*

 at the end of

recording.

T

 The information written in the UTOC includes the recorded track numbers and their addresses, text data, etc.

C2.

Performs the necessary displays of the text data recorded on the disc and for each operation.
The system is designed for integrated operation, so that the system control IC (IC10) on the MD servo PCB and the system
control IC (IC901) for the component system mutually exchange data (communicating).

T

 The controls of the playback signal, recording signals, and of the 4-channel driver IC (IC1:  AN8772) all function using the clock

on the MD LSI as the master clock.

T

 The A/D-D/A converter (IC601) functions by using the clock signal of the MD LSI as the master clock and frequency-sampling

that signal 384 times via the clock generator (IC501:  TC9246).

– 10 –

Play signal

A phenomenon in which the polarization plane of laser light reflected from a material shifts in one of two directions 

 

depending upon its “plus” or “minus” magnetic polarization.

The aim of Add-on interleave is to improve the resistivity in CD-ROM decoder from the burst error on the disc.

The digital data compressing system developed for MiniDisc in which audio signals can be reproduced with only about 

th 

1/5   in the data normally required for high fidelity reproduction

The temperature at which magnetism of a specific material dissipates. This temperature varies according to the material.

Found only on recordable MiniDiscs, this area contains subdata (track number, etc.) which can be rewritten by the user.

Magnetic
head

Magnetic head
Drive Q10,11

Traverse
motor

Spindle
motor

Optical
pickup

4ch driver IC
IC2   AN8814

    RF    IC
  IC1  AN8772

 MD LSI

IC3   MN66616
   EFM    mod/demo

          ATRAC    encoder /
                            decoder

   Servo signal processor

DRAM(4Mbit)
IC72  MNV4400

Loading motor

Detection SW

Loading drive
IC92  LB1830

    20bit AD /DA converter

  IC601  AK4520

Buffer AMP
IC711   BA4560

Buffer AMP
IC751   BA4560

Head Phone AMP
IC801   M5218

OPTIAL OUT

LINE IN

LINE OUT

H.P. OUT

Interface
IC401 TC74HTC7007

System control
IC901
M30218

FL display

Operation SW

System control
IC10
MN101D03D

Clock
10.02MHz

Clock
16.9334MHz

Clock
10MHz

OPTIAL IN

Interface  IC402
TC74HC4050

Clock
generator
IC501
TC9246

DISC

 

 

REC signal

Clock line

Control line

1        2      24      25

43   44   45   46

73

97

70

69

65

64

71

32

2

3

9

4

8

3

3

5

13

14

0.5

¨

s. 50mV/DIV.

0.45V
P-P

0.5

¨

s. 0.1V/DIV.

0.9V
P-P

0.5

¨

s. 1V/DIV.

3.2V

0V

3.2V

0V

T = 11

¨

s.

. .

0.2

¨

s. 2V/DIV.

3.2V

0V

0.2

¨

s. 2V/DIV.

4.8V

0V

4.8V

0V

T = 0.34

¨

s.

. .

1kHz, 0dB

3.2V
P-P

1kHz, 0dB

6.2V
P-P

1kHz, 0dB

VOLUME CENTER

170mV
P-P

39

38

– 11 –

Switch power ON

 with no MD loaded.

Does player

 enter self-check 

mode? *1

Set to read power 

adjustment mode. *2

Is read power output?

Can read 

power be set to 600

¨

W 

or lower using 

VR1?

Faulty optical pickup

Set to write power 

adjustment mode. *3 

Is write power output?

Adjust write power and 

check ROM data laser 

power and RAM data 

laser power.

To "ROM/RAM Operation" 

(page ?)

Is CN4 power 

supply line OK?

Is oscillation 

signal output from IC10 

pin 33?

Check power supply 

circuit on main unit.

Faulty IC10

Is IC10 pin 21 "H"?

 (Continued on next page.)

O
U

S
[

T

5V

5V

5V

3.3V

3.3V

CN4

Check reset circuit 

on main unit.

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES

NO

YES

IC10 pin 33

*1 : See Srevice Manual page 35.

*2 : See Srevice Manual page 69.

*3 : See Srevice Manual page 69.

 (Continued on next page.)

10.02MHz

Is CN4 pin 14 "H"?

$

– 12 –

Is output 

voltage of IC1 pin 37 

(TP35) approx. 

1.3 V *1

 Is voltage 

on both sides of R5 

at least 0.025 V?

NO

YES

NO

YES

Faulty optical pickup

Is there 

output from IC3 

pin 92?

 Is voltage of 

IC1 pin 2 (left side of R8) 

approx. 1.8 V?

*1

 Is voltage 

on both sides of R5 

at least 0 V?

Is voltage 

of IC1 pin 36 

2.6 V? *1

YES

Is current 

flowing equal to at 

least 1.2 times value 

indicated on pick 

FPC? *2

YES

NO

Is output of 

IC3 pin 92 OK?

Is voltage of 

IC1 pin 2 (left side of R8) 

approx. 1.9 V?

*1

NO

YES

NO

YES

NO

YES

3.3V

0V

3.3V

0V

NO

YES

NO

YES

*2: Indicated value:  
     Current equal to that on both 
     sides of R5 divided by 1 

≠

Faulty IC1

Is voltage 

of IC9 pin 3

2.6 V? 

YES

Faulty L5

Faulty IC9

NO

NO

Faulty IC3

Faulty IC1

Faulty optical pickup

See Service Manual page 27 
for measurements of IC1.

*1:

Faulty Q1

Faulty optical pickup

Faulty IC1

Faulty IC3

Faulty optical pickup