Technics SJ-MD100 Service Manual Download

Page: 11 / 16

SJ-MD100

– 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

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
[

3.3V

CN4

Check reset circuit

on main unit.

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"?

Troubleshooting Guide for MD Servo Circuit

Summary of Contents for SJ-MD100

Page 1: ...tsushita Electric Industrial Co Ltd All rights reserved Unauthorized copying and distribution is a violation of law ORDER NO AD9903069S2 Colour K Black Type Areas E Europe EB Great Britain EG Germany SJ MD100 Minidisc Deck This document is supplementary to the following Service Manual Supplement for technical information about MD Contents Area Code E EB EG Order No MB9902001C2 Model No SJ MD100 1 ...

Page 2: ...f MD T Definition of an MD and the types of MDs Y MD stands for mini disc Y Similar to a music CD an MD is also a small disc capable of recording and playing back digital sound Y There are 2 types of MDs a optical disc for playback only MD and a magnet optic disc for recordable MD that is capable of both recording and playback Y A playback only MD is merely a smaller diameter version of a CD Just ...

Page 3: ... if a downward facing south north external magnetic field is applied the direction of the magnetism at that location is changed to face downward south north Y Then when the disc rotates and the location which has been changed to upward facing magnetism leaves the laser spot the temperature of the magnetic film drops and the upward facing magnetism recorded at that location is retained Y In this wa...

Page 4: ...o further explain the principle used to read the signals recorded on a magnet optic disc first a laser beam is directed at the disc If the direction of the magnetism recorded on the disc is upward north polarity the plane of polarization of the light reflected from the disc rotates very slightly clockwise as a result of the Kerr effect Conversely if the direction of the magnetism is downward south...

Page 5: ...g recorded is 1 or 0 the direction of the magnetic field also changes between north and south and accordingly the direction of the magnetization of the recording film changes between upward facing and downward facing Thus it is possible to directly magnetize the recording film on the disc in accordance with the 0 and 1 digital signals Y Thus the new recording data is overwritten regardless of the ...

Page 6: ...because the addresses are already recorded around the entire circumference of the disc when the MD is recorded those addresses are read in order to control the movement of the optical pickup and perform CLV control Y To record immediately quick access is first performed to quickly search for an blank area on the disc and then recording will automatically begin When recording is completed that addr...

Page 7: ...best part of the fresh orange is concentrated for easy transportation and then reconstituted with water before drinking Y The basic concept of ATRAC utilizes the characteristics of the human auditory sense The frequency spectrum that cannot be heard by the human ear Fig B and the frequency spectrum that cannot be heard because it is masked by high level sounds Fig C are cut and the bit rate is com...

Page 8: ...e rotation speed so that the servo signal is obtained at a constant linear speed at the location being read Y This is the main signal processing LSI EFM is a circuit which converts 8 bit digital signals into the 14 bit format recorded on the disc It also performs signal processing for error correction changing the interleaving format in order to use the ideal algorithm for MD In addition this LSI ...

Page 9: ...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...

Page 10: ...a 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 signalprocessor DRAM 4Mbit IC72 MNV4400 Loading motor Detection SW Loading drive IC92 LB1830 20bit AD DA converter IC601 AK4520 Buffer AMP IC711 BA4560 Buffer ...

Page 11: ...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 1 Continued on next page 2 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 p...

Page 12: ...nt flowing equal to at least 1 2 times value indicated on pick FPC 2 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 ...

Page 13: ...REC H L H L H 3 3V L 0V 5 NO IC3 pin 21 Faulty IC3 Faulty IC2 Does optical pickup move up and down Continued on next page Does CN4 pin 18 change from H to L when disc is inserted Faulty loading TRG S7 D i s c t r a y O P E N L H H H Is output of IC10 pins 13 15 17 and 18 OK Is voltage of IC10 pins 8 and 9 OK Is voltage output from IC92 pins 2 and 4 Faulty loading motor Faulty S3 S4 S5 and S6 Fault...

Page 14: ... of IC1 pin 11 be adjusted so that it is approx symmetrical with a level of 1 5 Vp p 1 Faulty IC1 or optical pickup Is RF waveform output from IC1 pin 32 TP52 1 Is there output from IC1 pin 29 TP148 or IC3 pin 87 1 IC1 pin 29 TP148 or IC3 pin 87 Is RF signal stable Are communications between IC3 and IC72 OK Communications error Is voltage output from IC3 pin 96 Faulty IC1 Faulty IC1 Faulty IC3 Fau...

Page 15: ... 1 of a previously recorded MD Is playback sound OK Insert a recordable MD Is recording possible Operation complete Faulty magnetic head Faulty magnetic head Is shape of magnetic head OK Is there output from CN8 TP110 and TP111 Is output of IC3 pin 73 OK Faulty magnetic head circuit Faulty IC3 Is output of IC3 pins 61 65 OK during playback 10 9344MHz Faulty audio circuit Faulty IC3 To page 10 Afte...

Page 16: ...emains at outer track Is IC10 pin 12 approx 3 3 V Faulty traverse detection switch S8 Is IC10 pin 12 approx 0 V Faulty shorted traverse detection switch S8 or Is output of IC3 pin 20 OK Is voltage output between IC2 pins 15 and 16 Faulty IC2 Faulty IC3 Faulty traverse motor Printed in Japan F990406500MT KH D ...

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