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MINI DISC RECORDER
DM-VH7
SERVICE MANUAL
© 1999-6/B51-5544-00 (K/K) 3632
70%
646
609
608
606
617
607
619
660
rec level
recording
eject
standby
enter
stop
rec
o.t.e.
on/standby
mode
disc loading mechanism
minidisc recorder DM-VH7
20bit A/D&D/A converter
654
601
A1-A2
611
602
J1
J3
632
610
DIGITAL IN
OPTICAL
SYSTEM
CONTROL
L
R
REC
IN
PLAY
OUT
12
Knob
(K29-7554-04)
AC power cord bushing
(J42-0083-05)
AC power cord *
(E30-)
Metallic cabinet (TOP)
(A01-3696-01)
Optic receiving module
(W02-1181-05)
Panel
(A29-1051-14)
Dressing panel
(A21-3762-13)
Knob *
(K29-)
Front glass
(B10-3486-03)
Side plate R
(A50-1326-02)
Rectangular receptacle
(E08-0312-05)
Phono jack
(E63-1065-05)
Metallic cabinet
(BOTTOM)
(A01-3698-01)
Side plate L
(A50-1327-02)
Indicator
(B12-0361-04)
Insulator assy
(J02-1444-14)
Dressing panel (BOTTOM)
(A21-3758-02)
Dressing panel (TOP)
(A21-3757-12)
Do not face the light of laser when a repair or action confirmation are done.
* Refer to parts list on page 27.
Refer to X-VH7 service manual (B51-5532-00), if need Disassembly for repair.
DM-VH7(K) COVER1,1P( 99.10.29 2:43 PM y[W 2


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2ABC
1
3DEF
5JKL
6MNO
4GHI
8TUV
9WXY
7PRS
EDIT
CANCEL
0QZ
,
,
:
?
+10
&
(
)
-/
+100
RANDOM
REPEAT
CHECK
/SPACE
P.MODE
/CHARAC.
CLEAR
DELETE
EDIT
SET
ENTER
87
¡
14
¢
REC
MODE
TIME
DISP.
TITLE
SEARCH
MONITOR
REMOTE
CONTROL
UNIT
RC-M0708
O.T.E.
÷
PLAY
£
TITLE
INPUT
REC
INPUT
POWER
Audio cord (2)
(E30-0615-05)
(A70-1279-05)
(J02-0130-05)
(J19-5996-02)
Battery cover (A09-1106-08)
(E30-2628-05)
(B19-1529-05)
(W01-0084-05)
System control cord (1)
Optical fiber cable (1)
Remote control unit (1)
Batteries (R6/AA) (2)
Check that the following accessories are present.
Spacer (1)
Replacement front feet (2)
Allen wrench (1)
DM-VH7
2
CONTENTS / ACCESSORIES / CAUTIONS
CONTENTS / ACCESSORIES / CAUTIONS ............. 2
CIRCUIT DESCRIPTION ............................................3
MECHANISM DESCRIPTION...................................11
PC BOARD .............................................................. 14
SCHEMATIC DIAGRAM .......................................... 16
EXPLODED VIEW ....................................................25
PARTS LIST..............................................................27
SPECIFICATIONS ......................................Back cover
Contents
Accessories
Cautions
System configuration
Operation to reset
The microprocessor may fall into malfunction (impossibility
to operate erroneous display, etc.) when the power cord is
unplugged while power is ON or due to an external factor.
In this case, execute the following procedure to reset the
microprocessor and return it to normal condition.
Unplug the power cord from the power outlet then, while
holding the eject (
0 eject) key depressed, plug the power
cord again.
¶ Please note that resetting the microprocessor clears
the contents stored in, it returns the microprocessor to
the condition when it left the factory.
Note related to transportation and
movement
Before transporting or moving this unit, carry
out the following operations.
1. With no disc loaded in the unit, press the "on/
standby" key to on.
¶ Check that no disc is present in the unit.
2. Wait a few seconds and verify that the display
shown appears.
3. Press the "on/standby" key to off (standby).
CAUTION :
Use of controls or adjustments or performance of proce-
dures other than those specified herein may result in
hazardous radiation exposure.
In compliance with Federal Regulations, following are re-
productions of lables on, or inside the product relating to
laser product safety.
For the U.S.A.
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KENWOOD CORPORATION
2967-3, ISHIKAWA-CHO,
HACHIOJI-SHI, TOKYO, JAPAN
KENWOOD CORP. CERTIFIES THIS
EQUIPMENT CONFORMS TO DHHS
REGULATIONS NO. 21 CFR 1040.10,
CHAPTER 1, SUBCHAPTER J.
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Location: Back Panel
CD RECEIVER
CASSETTE DECK
SPEAKERS
VH-600
RD-VH7
­
LS-VH7
VH-700
RD-VH7
X-VH7
LS-VH7
DM-VH7(K) COVER1,1P( 99.10.29 2:43 PM y[W 3


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DM-VH7
3
CIRCUIT DESCRIPTION
Backup item
Initialization
· MONITOR
OFF
· REC INPUT
ANALOG
· REC INPUT/ LEVEL
ANALOG=-12dB
· REC mode
TNO MARK
AUTO
TNO MARK LEVEL
0(-55dB)
(MD ucom)
1. Backup and initialization
2. MD microprocessor M30620MC-340FP(X25: IC11)
2-1 Micoprocessor periphery block diagram
· The case of the system connection don't memorise
REC INPUT,REC LEVEL and stand up the same
initialization. System ON/OFF and POWER
ON/OFF are memorised the last selector position.
· The case of DISC exist editing record : the set dont
read TOC at AC power on
_ Setting of the initialization
While pressing the EJECT key, plug an AC power cord
into AC outlet.
No backup item
Initialization
PLAY mode
TRACK MODE
REPEAT
OFF
(MECHA ucom)
Backup item
Initialization
DISC editing record
UTOC information
DIN
AIN AOUT
UART
A/D
INT
PWM
PWM
SIO
Mechanism unit
(X33)IC24
MECHA uCOM
HD6432227N01FA
Main uCOM
M30620MC-340FP
(X25)IC12
DISPLAY
LCD driver
(64 x 64 full_dot)
LCD module
HD6433297A17F
uCOM
standby
eject
rec
REM
Key matrix
(2 x 6)
Back up
circuit
Din1
Din2
REC
PLAY
SL16
vol
MUTE
(X25)IC11
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DM-VH7
4
CIRCUIT DESCRIPTION
Pin No.
Name
I/O
Description
1
VOL_DT
O
Electric VOL IC · communication data
2
VOL_CK
O
Electric VOL IC · communication clock
3
-
O
Not used
4
DISP_CE
O
Display ucom · communication CE
5
DISP_OUT
O
Display ucom · communication data output
6
DISP_IN
I
Display ucom · communication data input
7
DISP_CLK
O
Display ucom · communication clock
8
BYTE
-
Ucom mode data bus setting
9
CNVss
-
Ucom mode · inner ROM
10,11
-
-
Not used
12
RESET
I
Ucom reset
13
Xout
O
Ucom oscillation 10MHz output
14
Vss
-
GND
15
Xin
I
Ucom oscillation 10MHz input
16
Vcc
-
Power supply
17
NMI
-
Ucom compulsion thrust
18
-
O
Not used
19
CE
I
Ucom CE
20
REM
I
Remote control input
21
DISP_RST
O
Display ucom reset
22
LCD_BL
O
LCD backlight (Dimmer)
23
POWER
O
Power supply circuit
H: ON
24
LED_EJECT
O
LCD · EJECT(Dimmer)
25
BACK_V_CHK
O
Backup voltage check circuit
H: ON
26
BACK_V_ON
O
Backup charge
H: ON
27
MECHA_CE
O
MD mecha. ucom CE
28
MECHA_RST
O
MD mecha. reset
L: RESET ON
29
MECHA_RXD
I
MD mecha. communication input
30
MECHA_TXD
O
MD mecha. communication output(N-ch)
31~34
-
-
Not used
35
TIRLER_TXD
O
Titular communication output
36
TIRLER_RXD
I
Titular communication input
37
SDATA
I/O
Serial data (SL16)
38
SBUSY
I/O
Serial busy (SL16)
39
RDY
I
Extension bus control
40
-
-
Not used
41
HOLD
I
Extension bus control
42~61
-
-
Not used
62
Vcc
-
Ucom power supply (5V)
63
-
-
Not used
64
Vss
-
Ucom power supply (GND)
65~74
-
-
Not used
75
AMUTE
O
Analog mute
76,77
-
-
Not used
78
LED_REC
O
LED REC
79
-
-
Not used
80
LED_STBY
O
LED STANDBY
81~88
-
-
Not used
89~91
KR0~2
I
Key return
92
BACK_V
I
Backup voltage check
93
INISW
I
Destination switch
H: except J type
94
XY_POSITION
I
X-Y position
95
I_PROTECTION
I
Current protection
96
AVss
-
A/D power supply (GND)
97
-
-
Not used
98
Vref
-
A/D reference voltage (5V)
99
AVcc
-
A/D power supply (GND)
100
VOL_LEN
O
Electric VOL IC · communication data latch
2-2 Pin description
DM-VH7(K) COVER1,1P( 99.10.29 2:43 PM y[W 7


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DM-VH7
5
CIRCUIT DESCRIPTION
Voltage(V)
KR0 (89)
KR2 (91)
KR1 (90)
Threshold
voltage(V)
5.00
(no key on)
(no key on)
(no key on)
4.59
4.17
-----
eject
-----
3.75
3.33
power/standby
o.t.e.
-----
2.92
2.50
stop
ff/level_up
-----
2.09
1.67
down
up
-----
1.25
0.88
fb/level_down
play/pause
-----
0.42
0.00
rec
mode
-----
2-3 Key matrix
3. MD mechanism microprocessor HD6432227N01FA(X33: IC24)
3-1 Microprocessor periphery block diagram
(X33)CI2
(X33)IC24
MNT0
ATRAC
MD ucom
AD/DA
MNT1
CXD2654R
MNT2
MNT3
(X25)IC11
SWDT
SCLK
CTXD
XLAT
CRXD
SRDT
SENS
XRST
SQSY
DQSY
(X33)IC12
RECP
XINT
ADDARST
TX
EMPHA
LDON
CXA2523AR
RMS
HMUTE
(X33)IC6
SRVMOD
E2PROM
MECHA
RF amp
SCL
SDA
POWER
IDSW
MUTE
HEADPOS
MUTE_BAR
MDM-06
DISCIN
RESET
STTLMT
CE
LOADIN
LOADOUT
BITRATE
DM-VH7(K) COVER1,1P( 99.10.29 2:43 PM y[W 10