Kenwood MDXG-3 Service manual

70%

MD PERSONAL STEREO SYSTEM

APE T

MDX-G3

SERVICE MANUAL

© 2001-1/B51-5697-00 (K/K) 329

Arm
(D10-3983-04)

Handle
(K01-0127-03): L
(K01-0143-03): SR

Dressing panel
(A21-3897-03): L
(A21-3926-03): SR

Knob ass'y
(K29-7870-04): L
(K29-7918-04): SR

Panel ass'y
(A60-1975-11): L
(A60-1982-11): S
(A60-1986-11): R

Rod antenna
(T90-0828-05)

Miniature phone jack
(E11-0399-05)

AC inlet
(E03-0374-05)

L: BLUE, S: SILVER, R: RED

In compliance with Federal Regulations, following are repro­duction of labels on, or inside the product relating to laser
product safety.

Note: Please contact KENWOOD service in your side if

you want to get the AC power cord.

KENWOOD-Crop. certifies this equipment conforms to DHHS
Regulations No.21 CFR 1040. 10, Chapter 1, subchapter J.

DANGER : Laser radiation when open and interlock defeat­ed.

AVOID DIRECT EXPOSURE TO BEAM.

Plastic cabinet ass'y
(A02-2996-01)

Miniature phone jack
(E11-0399-05)

POWER cord (1)
(E30-2927-05)

Remote control unit (1)

Battery cover (A09-1151-08)

(A70-1449-05)

Batteries(R6/AA)
for remote (2)

AM loop antenna (1)
(T90-0865-05)

MDX-G3

CONTENTS / ACCESSORIES / CAUTIONS

Contents

CONTENTS / ACCESSORIES / CAUTIONS............. 2

EXTERNAL VIEW .......................................................3

DISASSEMBLY FOR REPAIR....................................4

CIRCUIT DESCRIPTION ............................................5

ADJUSTMENT ..........................................................10

WIRING DIAGRAM ...................................................12

Accessories

PC BOARD .............................................................. 13

SCHEMATIC DIAGRAM .......................................... 16

EXPLODED VIEW ....................................................29

PARTS LIST..............................................................31

SPECIFICATIONS ....................................................39

Cautions

Operation to reset

The microcomputer may fall into malfunction when a cord is
unplugged and plugged again while the unit is ON or due to an
external cause. In such a case, the microcomputer should be reset
as described below:
Unplug the power cord from the wall outlet and, while holding the
POWER key depressed, plug the power cord again. This initializes
the microcomputer. Note that this clears the previously stored
memory.

Note related to transportation and move­ment

Before transporting or moving this unit, carry out the following oper­ations.

1. Remove the CD or MD from the unit.

2. Press the MD 6 key.

3. Wait for some time and verify that the display becomes as
shown in the figure.

4. Press the CD 6 key.

5. Wait for some time and verify that the display becomes as
shown in the figure.

6. Wait a few seconds and turn the unit off.

Memory backup function

Stored contents which are cleared immediately when power plug is
unplugged from power outlet.

- Clock display(Backed up for 3 min.)

Stored contents which are cleared in at least a day after power
plug is unplugged from power outlet.

¶¶

Amplifier section

- Input selection

- Volume control value

- AUX input level

- Tone control levels

- Timer setting contents

¶¶

Tuner section

- Receiving band

- Frequency

- Preset stations

- Auto tuning setting

¶¶

Cassette deck

- Tape transport direction

- Tape equalizer

- Tape reverse mode

¶¶

MD recorder

- Recording mode

- Recording speed

2

CD/MD HIGH SPEED DUBBING SYSTEM

1

B

I

T

D

U

A

L

D

/

A

C

O

N

V

E

R

T

E

R

Top cover ass'y
(A52-0920-21): L
(A52-0922-21): S
(A52-0924-21): R

MDX-G3

EXTERNAL VIEW

Rod antenna
(T90-0828-05)

3

MDX-G3

SP CONNECTOR

X09 (G/7) -CN502

X28-CN1

1

1

1

1

2

1

1

2

2

x3

FRONT SIDE

4

3

3

3

5

4

4

FRONT SIDE

FRONT SIDE

FRONT SIDE

x3

DISASSEMBLY FOR REPAIR

1. How to Remove Front Panel

1. Remove 6 screws(1) from the rear side.

2. Remove 2 screws(2) from the bottom side.

3. Slide the front panel frontwards and pull out the connec­tors and FPC.

4. Remove the front panel from the rear cabinet.

2. How to Remove Top Panel

1. Remove 3 screws(3) from rear side.

2. Remove 3 screws(4) from top side.

3. Remove 3 screws(5).

4. Lift the top cover.

Note: You need to pull out FPC on the rear side of top cover.

4

CIRCUIT DESCRIPTION

MDX-G3

1. Initializing

1-1 Initialization Method

• While pressing the [POWER] key, turn the AC on.

1-2 Initialization Operation

• During the initial operation, the display shows "INITIAL­IZE "and after that it will be retuned to standby condi­tion.

• If any mechanisms error occurred, the error indication
is displayed as "ERR" on the display.

1-3 Mechanism Initialization

1 CD Mechanism

• If a mechanism error occurred, the error indication is
displayed as "C ERR" on the display.

2 Deck Mechanism

• If a mechanism error occurred, the error indication is
displayed as "T ERR" on the display.

3 MD Mechanism

• If a mechanism error occurred, the error indication is
displayed as "M ERR" on the display.

• The disc will be unloaded from MD mechanism auto­matically, if a disc is its in.

4. Microprocessor : MN101C49KLA(X09,IC11)

4-1 Microprocessor Periphery Block Diagram

2. Tuner Destination

Destin-

Set

M E1 FM 87.5MHz 108.0MHz 50kHz +10.7MHz 25kHz
M E1 AM 531kHz

Band

ation Frequecy Range Space

Receiving Channel

1602kHz 9kHz +450kHz 9kHz

IF RF

3. Tuner Preset Frequency

P.CH Band Frequency P.CH Band Frequency

1 FM 98.30MHz 16 FM 98.00MHz
2 FM 87.50MHz 17 FM 98.50MHz
3 FM 108.00MHz 18 FM 87.50MHz
4 FM 89.10MHz 19 AM 990kHz
5 FM 90.00MHz 20 FM 97.70MHz
6 FM 87.50MHz 21 AM 531kHz
7 FM 87.50MHz 22 FM 87.50MHz
8 FM 87.50MHz 23 FM 87.50MHz

9 AM 1602kHz 24 FM 87.50MHz
10 AM 999kHz 25 FM 87.50MHz
11 AM 630kHz 26 FM 87.50MHz
12 AM 1440kHz 27 FM 87.50MHz
13 FM 106.0MHz 28 FM 87.50MHz
14 AM 531kHz 29 FM 108.0MHz
15 FM 87.50MHz 30 AM 945kHz

DOT DRIVER
(M66004-001FPG)

51

X09,ED501

Vaccume Fluorescent
Display (HNA-16MM30T)

X09,IC22

DSP IC
(MN662748RPMFA)

CD MECHA
(KSM213CDM)

X28,IC1

DECK SYSTEM IC

MD MECHA
MDM-07

6

3

4

5

DECK MECHA.
(ADR-2176TR3)

X09,IC1

2

X09,IC21

SYSTEM IC
(M61510FP)

MN101C49KLA

6

3

3

3

X09,IC32

PLL IC
(LC72131)

2

KEY

KEY1,2

REMOTE

X09,A501

2

ENCODER

X09,S517

5

MDX-G3

CIRCUIT DESCRIPTION

4-2 Key Matrix Input Voltage Value : 4.6V

Input Voltage(V) KEY2(Pin7) KEY1(Pin8)

0.00 0.45 POWER BEST HITS

0.43 1.10 SOUND MD REC

1.13 1.78 AUX TAPE REC

1.81 2.37 SKIP DOWN TUNER

2.41 2.80 SKIP UP CD PLAY/PAUSE

2.84 3.25 STOP MD PLAY/PAUSE

3.29 3.68 MD EJECT TAPE PLAY

3.72 4.22 MENU SET/DEMO

4.24 4.60 KEY OFF KEY OFF

4-3 Voltage Value of Control Port

1 Deck Reel Pulse

Input Voltage

0.00~1.94 LOW

1.95~2.91 -

2.92~4.6 HIGH

(V) Active

4-4 Port Description of Microprocessor

Port No. Port Name I/O Description

1 GND Connected to ground.
2 PHOTO I Deck reel sensor input.
3 TYPE I Discrimination of tuner destination.
4 PROTECTION I Detection port for power supply protection.
5 CD PROTECT I Detection port for CD protection.
6 MD BACKV I Detection port for MD back up voltage.

7,8 KEY2,KEY1 I A/D key (1,2) input.

9 KEY3 Unused.
10 VREF+ A/D reference voltage input for the A/D converter.
11 VDD Power supply input (+5V).
12 OSC2 O Main clock output (8.38MHz).
13 OSC1 I Main clock input (8.38MHz).
14 GND Connected to ground.
15 XI I Timer clock input (32kHz).
16 XO O Timer clock output (32kHz).
17 GND Connected to ground
18 MD TXD O MD communication TX (to mecha. u-com RX).
19 MD RXD I MD communication RX (to mecha. u-com TX).
20 NC - Unused.
21 FL SDATA O Data output to FL dot driver.
22 NC - Unused.
23 FL SCLK O Clock output to FL dot driver.
24 FLRESET O Reset output to FL dot driver. Reset
25 FL CE O CE output to FL dot driver.
26 REM I Remote control signal input.
27 MODEL TYPE I Discrimination port for model type. Fixed
28 CD BLKCK I Sub code synchronous signal input.
29 RDSCLK - Unused.

30,31 ENC A,B I Volume encoder (A/B) input.

32 VDD2 - Microcomputer power supply (+5v).
33 RESET I Reset signal input for microcomputer. Reset
34 CE I Back up detection input. AC On AC Off
35 OP/CL SW I Input port of detection switch for CD open/close.
36 SLTSW I CD start switch input.

6

37 XRST O CD DSP reset output. Reset

38~40 NC - Unused.

2 Tuner Destination(Pin3)

Input Voltage(V) Type

0.00~2.50 J(Japan)

2.51~4.6 M(Asia)

3 Voltage Protection(Pin4)

Input Voltage(V) Protection

0.00~2.50 ON

2.51~4.6 OFF

4 CD Protection(Pin5)

Input Voltage(V) Protection

0.00~1.49 ON

1.50~3.49 OFF

3.50~4.6 ON

Active

HL

CIRCUIT DESCRIPTION

MDX-G3

Port No. Port Name I/O Description

41 VPP - Microcomputer power supply (+5v).
42 MDATA O CD DSP command data output.
43 STAT I CD DSP status signal input.
44 MCLK O CD DSP command clock signal output.
45 MLD O CD DSP command load signal output.
46 SUBQ I CD sub code input.
47 SQCK O Clock output for CD sub code.
48 EEP SDA - Unused.
49 EEP SCL - Unused.
50 HI SPEED - Unused.
51 OPEN - Unused.
52 CLOSE - Unused.
53 MD CE I Detection port for MD back up.
54 MD RST I Reset output from MD mechanism.
55 INI MD SW I Unused.
56 BACK CHK - Unused.
57 BACK ON - Unused.
58 MD IN SW I Load switch input for MD disc.
59 NC - Unused.
60 PLAY SW I Detection switch input of head position for deck.
61 CrO2 SW - Unused.
62 HALF SW I Cassette half switch input.
63 REC F SW I Deck forward recording switch input. OFF ON
64 CPM O Control port of capstan motor for deck.
65 REC R SW I Deck reverse recording switch input. OFF ON
66 SOL O Control port of solenoid for deck.
67 LMUTE O Deck line mute control. ON
68 A/B-1 O Deck recording mute & head select control 1.
69 A/B-2 O Deck recording mute & head select control 2.
70 Bø/¿ - Unused.
71 NOR - Unused.
72 BIAS O Control port of bias on/off for deck. ON OFF
73 R/P O Deck recording & playback changeover. Recording Playback
74 BEAT_C O On/off control port of beat cancel for deck. ON OFF
75 NC O Unused.
76 EVCLK O Sound controller clock output.
77 EVDATA O Sound controller data output.
78 ST - Unused.

79,80 NC - Unused.

81 LED STBY GRN O Standby led(green) control port. OFF ON
82 LED STBY RED O Standby led(red) control port. OFF ON

83,84 NC - Unused.

85 CD POWER O CD DSP power on/off changeover control. ON OFF
86 AMP ON/OFF O On/off control port for amplifier circuit.
87 AMUTE O Audio mute output.
88 POWER O Power relay control.

89~92 NC - Unused.

93 ST I Stereo detector input.
94 SD I SD detector input.
95 GND - Connected to ground.
96 PLL DATA O PLL IC data output.
97 PLL CLK O PLL IC clock output.
98 PLL DO I PLL IC data input.
99 PLL CE O PLL

100 DAVDD I D/A converter positive voltage.

IC chip enable output.

Active

HL

7

MDX-G3

5. Test Mode

5-1 Setting method of the Test Mode

TEST MODE SETTING METHOD

CD MODE CD PLAY Key + AC-ON

MD MODE MD PLAY Key + AC-ON

DECK MODE TAPE PLAY/REVERSE Key + AC-ON

SUB CLOCK OSC STOP Key + AC-ON

DIAGNOSIS

The oscillation diagnosis(existence of oscillation and mea­surement of period) of a sub clock is performed before the
test mode is entered. If the diagnosis result is OK, the sys­tem enters the test mode.
If the diagnosis result is NG, the oscillation of the sub clock
is diagnosed again. If the result is OK, the system enters
the test mode. If the diagnosis result is continuously NG 5
times, the system stops with "ERR1"and "ERR2"displayed.

5-4 CD Test Mode

KEYS DISPLAY OPERATION

CD-PLAY/PAUSE 05

(Cyclically changed the mode 03

05 and 03 by pressing the key.) ( : )Time Display Tracking-servo off.

CD STOP 01 --:-- Stop the CD operation.

(Cyclically changed in the 07 FG/FE FG value /FE value

stop mode only.) 08 FB/FO FBAL value /FO value

SKIP UP Ex.01~02 Track No up.

SKIP DOWN Ex.02~01 Track No down.

SKIP UP Normal Indication Play the first track No in the stop mode.

SKIP DOWN Normal Indication Play the last track No in the stop mode.

BEST HITS CD FF search.

SOUND CD FB search.

CIRCUIT DESCRIPTION

5-2 Cancel of the test mode

• By turning the AC off, the system is initialized and the test
mode is canceled.

• Cancel the test mode only if the power switch is turned
off.

5-3 Contents of the Test Mode

• The muting during mode selection is not controlled in the
test mode.

• During the test mode, it can be operated in a special man­ner that is defferent from an ordinary operation by using
the keys on the main body, specifically as shown in the
next page.

:

( : ) Time Display Tracking-servo on.

:

Adjustment value/mean value

09 TG/TE TG value /TE value
10 TB/TO TBAL value /TO value

The pickup travels outward in the stop mode.

The pickup travels inward in the stop mode.

5-5 Deck Test Mode

KEYS DISPLAY OPERATION

TAPE REC TAPE

SOUND Beat-C ON Beat cancel will be on while pressing the sound key.

MENU NORMAL Changeover the EQ. on/off cyclically.

8

4 Seconds Recording
If the REC/ARM key is pressed, the system record for 4 seconds.
Then, it rewinds to the REC starting position and plays back automatically.
If the REC/ARM key is pressed, during the 4 seconds REC operation, the system
records further for 4 seconds, then returns to the starting position of the first 4 seconds
REC operation and plays back.

INDICATION

MDX-G3

CIRCUIT DESCRIPTION

Mechanism half switches indication The mechanism half switches status are indicated "blank" or "E "on the display.

7th Dot(Display) 1st figure 2nd figure 3rd figure 4th figure

Mechanism FWD REC Inhibit RVS REC Inhibit CrO2(TYPE¿) Cassette Half
Half Switch Detection SW Detection SW Detection SW Detection SW

ON Blank Blank Blank Blank

OFF E E E E

5-6 MD Test Mode

KEYS DISPLAY OPERATION

BEST HITS Normal Indication Hi-speed O.T.E.(CDîMD) operation in the stop mode.

FF MD FF search in the play mode.

SOUND DIGITAL or ANALOG The digital and analog can be changed cyclically by pressing the "SOUND" key.

FB MD FB search in the play mode.

STOP 01 -- : -- Stop the MD operation.

MD REC Normal Indication Start the MD recording with LP4 mode.

SET ALL ERASE Stop the MD operation and start operation of ALL- ERASE if disc is recordable.

9

MDX-G3

AM

ANTENNA

RF VC

CN23

(TAPE Rch),22 pin

X28 CN1

X09(E/7) P301

(TAPE Lch),20 pin

1

2

LD +5V

CN25

1

2

{

(B)(A)(C)

Fig.1

FM-MPX-SG

FM-MPX-SG POLAR SG

AC voltmeter AG

Dummy antenna

Oscilloscope AC voltmeter

Frequency counter

No.

ITEM

INPUT

SETTINGS

OUTPUT

SETTINGS

RECEIVER
SETTINGS

ALIGNMENT

POINTS

ALIGN FOR

FIG.

1 TUNING LEVEL

(A)

98.0MHz MONO

1kHz, ±75kHz dev.

37.2dBf (ANT. input)

(B)

MONO

98.0MHz

VR301

(X09)

Adjust VR1

and stop at the

point where

ED501(TUNED)

Fig.1

goes on.

FM SECTION : SELECTOR : FM

ADJUSTMENT

Cassette Deck adjustment

No

ITEM

ø. CASSETTE MECHANISM UNIT

Demagneti-

< 1 >

zation and

cleaning

Azimuth of

< 2 >

the

REC/PLAY

head

TAPE SPEED

< 3 >

(NORMAL)

¿. PC BOARD ADJUSTMENT

< 1 >

BIAS

CURRENT

INPUT

SETTING

–

SCC-1727

TCC−153
MTT−114

10kHz,

− 10dB

TCC−110
MTT−111

SCC−1727

3kHz

(C)

Connect the

AG to jack.

400Hz: -

20dBs

12.5kHz: ­20dBs

OUTPUT

SETTING

–

(B)

(B)

(B)

DECK

SETTING

Demagneti-

zation:

POWER OFF

Cleaning:

PLAY

PLAY

PLAY

REC and

PLAY

ALIGNMENT

POINT

Recording

head, erase

head,capstan

pinch roller

RVS FWD

Trimming pot

in the motor.

VR 1 (L)

VR 2 (R)

0dBs=0.775V

ALIGN FOR

Demagnetize the REC / PLAY head

with the head eraser.Clean the REC
/ PLAY head, erase head,capstan and
pinch roller using a cotton swab slight-

ly damped with alcohol.

Adjust the output to maximum and

adjust the azimuth adjustment screw

for the Lissajours waveform pattern of
the oscilloscope to become close to a

45° straight line.

Check the tape speed so that

3kHz(±2%) is obtained at the center

of the tape.

Record 400Hz and 12.5kHz alternate-

ly, and adjust the bias current adjust-

ment potentiometer for the playback

levels to become the same.

FIG.

Fig.1

Fig.1

Tuner adjustment

SYSTEM CONNECTIONS

10