Aiwa AM-LM918 User manual

SERVICE MANUAL
DATA
MINI DISC RECORDER BASIC MD MECHANISM : AZG-W YAF
AM-LM918
Y
S/M Code No. 09-016-446-9R1
REVISION
• This Service Manual is the “Revision Publishing” and replaces “Simple Manual”
AM-LM918 (Y), (S/M Code No. 09-015-446-9T1).
• If requiring information about the MD mechanism, see Service Manual of
AZG-W YAF, (S/M Code No. 09-015-355-9N2).

– 2 –
<MD recorder section>
Scanning method Non-contact optical scanner
(Semiconductor laser application)
Recording system Magnetic polarity modulation
overwrite system
Rotation speed Approx. 400 to 900 rpm (CLV)
Sampling frequency 44.1 kHz
No. of channels Stereo: 2 channels
Monaural: 1 channel
A/D, D/A converter 1-bit
Frequency 20 to 20000 Hz
Wow and flutter Unmeasurable
<Input>
AUX DIGITAL IN Sampling frequency: 48 kHz / 44.1 kHz / 32 kHz
Optical input level: more than -21 dBm
CD DIGITAL IN
<General>
Dimensions (W xH xD) 210 x 82.5 x 243 mm
Weight 1.3 kg
SPECIFICATIONS
• Design and specifications are subject to change without notice.
ACCESSORIES / PACKAGE LIST
DESCRIPTIONREF. NO. KANRI
NO.
PART NO.
1 87-B30-024-010 CABLE,OPTICAL MC-901 1M

– 3 –
This set employs laser. Therefore, be sure to follow carefully
the instructions below when servicing.
WARNING!!
WHEN SERVICING, DO NOT APPROACH THE LASER
EXIT WITH THE EYE TOO CLOSELY. IN CASE IT IS
NECESSARY TO CONFIRM LASER BEAM EMISSION.
BE SURE TO OBSERVE FROM A DISTANCE OF MORE
THAN 30cm FROM THE SURFACE OF THE OBJEC-
TIVE LENS ON THE OPTICAL PICK-UP BLOCK.
sCaution: Invisible laser radiation when
open and interlocks defeated avoid
exposure to beam.
sAdvarsel: Usynlig laserståling ved åbning,
når sikkerhedsafbrydere er ude af funktion.
Undgå udsættelse for stråling.
VAROITUS!
Laiteen Käyttäminen muulla kuin tässä käyttöohjeessa
mainitulla tavalla saataa altistaa käyt-täjän
turvallisuusluokan 1 ylittävälle näkymättömälle
lasersäteilylle.
VARNING!
Om apparaten används på annat sätt än vad som
specificeras i denna bruksanvising, kan användaren
utsättas för osynling laserstrålning, som överskrider
gränsen för laserklass 1.
PROTECTION OF EYES FROM LASER BEAM DURING SERVICING
Precaution to replace Optical block
(KMS-260E)
Body or clothes electrostatic potential could
ruin laser diode in the optical block. Be sure
ground body and workbench, and use care the
clothes do not touch the diode.
1) After the connection, remove solder shown in
right figure.
CLASS 1 LASER PRODUCT
KLASSE 1 LASER PRODUKT
LUOKAN 1 LASER LAITE
KLASS 1 LASER APPARAT
CAUTION
Use of controls or adjustments or performance of procedures
other than those specified herin may result in hazardous radiation
exposure.
ATTENTION
L’utillisation de commandes, réglages ou procédures autres que
ceux spécifiés peut entraîner une dangereuse exposition aux
radiations.
ADVARSEL
Usynlig laserståling ved åbning, når sikkerhedsafbrydereer ude
af funktion. Undgå udsættelse for stråling.
This Compact Disc player is classified as a CLASS 1 LASER
product.
The CLASS 1 LASER PRODUCT label is located on the rear
exterior.
MD PICK-UP Assy PWB
1VEE
¡TRK –
Pattern side
Solder
1
-

– 4 –
ELECTRICAL MAIN PARTS LIST
IC
87-A20-870-010 IC,GP1F37R
87-A21-175-040 C-IC,TC74VHC14FT
TRANSISTOR
87-A30-087-080 C-FET,2SK2158
87-A30-484-080 C-TR,KRA102S
87-A30-490-080 C-TR,KRC107S
87-A30-447-040 CHIP-TR,DTA114EKA
89-333-266-080 CHIP TR,2SC3326B
MAIN C.B
C901 87-010-759-080 C-CAP,U, 0.1-25F
C902 87-A12-061-080 CAP,E 47-10 SMG
C903 87-012-274-080 CHIP CAP,U 1000P-50B
C904 87-010-759-080 C-CAP,U, 0.1-25F
C905 87-A12-061-080 CAP,E 47-10 SMG
C906 87-012-274-080 CHIP CAP,U 1000P-50B
C907 87-010-759-080 C-CAP,U, 0.1-25F
C908 87-012-195-080 C-CAP,U 100P-50CH
C911 87-A12-064-080 CAP,E 1000-10 SMG
C913 87-012-197-080 C-CAP,U 150P-50 J CH
C914 87-012-197-080 C-CAP,U 150P-50 J CH
C915 87-010-757-080 C-CAP,U 0.047-25 Z F
CN901 87-A61-580-010 CONN,18P V WHT 52328
CN902 87-A60-423-010 CONN,14P V TOC-B
CN903 87-A60-422-010 CONN,8P V TOC-B
CN904 87-A60-586-010 CONN,4P V FE
FB909 87-A50-189-080 C-COIL,S BLM21B272S
FC902 8Z-CC3-607-010 FF-CABLE,14P 1.0 100MM
FC903 8Z-CC3-608-010 FF-CABLE,8P 1.0 100MM
JR902 87-005-840-080 C-COIL,S BLM21A10
88
A
Resistor Code
Chip Resistor Part Coding
Figure
Value of resistor
Chip resistor
Wattage Type Tolerance
1/16W
1/10W
1/8W
1608
2125
3216
5%
5%
5%
CJ
CJ
CJ
Form
LW t
1.6 0.8 0.45
2 1.25 0.45
3.2 1.6
108
118
128
: A
: A
CHIP RESISTOR PART CODE
0.55
Resistor Code
Dimensions (mm)
Symbol
1/16W 1005 5% CJ
1.0 0.5 0.35 104
Lt
W
FRONT C.B
CN905 87-A60-586-010 CONN,4P V FE
CNA908 88-805-020-640 CONN ASSY,2P 60MM
CNA909 88-805-021-090 CONN ASSY,2P
FC905 88-904-261-110 FF-CABLE,4P 1.25 260MM
S901 87-A90-696-080 SW,TACT TS2103-03-430
S902 87-A90-696-080 SW,TACT TS2103-03-430
S903 87-A90-696-080 SW,TACT TS2103-03-430
S904 87-A90-696-080 SW,TACT TS2103-03-430
S905 87-A90-696-080 SW,TACT TS2103-03-430
S906 87-A90-696-080 SW,TACT TS2103-03-430
S907 87-A90-696-080 SW,TACT TS2103-03-430
S908 87-A90-696-080 SW,TACT TS2103-03-430
S909 87-A90-696-080 SW,TACT TS2103-03-430
S910 87-A90-696-080 SW,TACT TS2103-03-430
S911 87-A90-696-080 SW,TACT TS2103-03-430
S912 87-A90-696-080 SW,TACT TS2103-03-430
LED-L C.B
C910 87-012-286-080 CAP, U 0.01-25
CN907 87-A60-619-010 CONN,2P V 2MM JMT
D901 87-A40-640-010 LED,SELU1E10CXM BLUE-EF
LED-R C.B
C909 87-012-286-080 CAP, U 0.01-25
CN906 87-A60-619-010 CONN,2P V 2MM JMT
D902 87-A40-640-010 LED,SELU1E10CXM BLUE-EF
DESCRIPTIONREF. NO. KANRI
NO.
PART NO. DESCRIPTIONREF. NO. KANRI
NO.
PART NO.

– 5 –
TRANSISTOR ILLUSTRATION
E
B
C
2SC3326B
DTA114EKA
KRA102S
KRC107S
S
G
D
2SK2158

WIRING (MAIN / FRONT / LED – L / LED – R)
32 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1
– 6 –
A
B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U

– 7 –
SCHEMATIC DIAGRAM (MAIN / FRONT / LED – L / LED – R)

– 8 –
MD TEST MODE
The following shows the contents of the test mode.
1. How to Activate MD Test Mode
2. MD Test Mode and Audio Output Check
3. How to Cancel MD Test Mode
4. How to Change to Servo Standby Mode
5. Sled Feed Operation Check
6. Laser Power Check
7. Loading Mechanism Operation and Detection Switch Check
8. Servo Operation Check
8-1 Focus Search/Spindle Kick Check 1
8-2 Focus Search/Spindle Kick Check 2 (S curve check)
8-3 Focus Servo and Sled Error (EF Balance) Check
8-4 All Servo On Check
9. Address, Error Rate Check
10. How to Erase U-TOC (User TOC)
1. How to Activate MD Test Mode
While pressing and holding the “PLAY” button on the MD section, insert the AC plug into the outlet.
* Notes: 1) The button operation in test mode is basically performed at MD section but it can also be done at TUNER section, AMP section and
CD section. The remote controller is also required for the adjustments.
2) During test mode activation, perform the operation and any mechanical error is ignored. If an unusual error occurs in the operation,
switch off the power immediately.
3) During test mode operation, normal recording/playback will not be working.
2. MD Test Mode and Audio Output Check
1) After activating test mode, the display will be as shown in the diagram below, indicating that test mode can be used.
2) Audio Output Check
The signal of 1kHz, –17dB (140mV) is the output from the MD mechanical output (D/A OUT).
(It cannot output from the speaker output and headphone output.)
3. How to Cancel MD Test Mode
1) Press the “MD EJECT” button and take out the DISC.
2) Remove the AC plug.
* Note: If the MD test mode is cancelled without using the above steps, the unit may not be able to operate properly when power is switched on
again. If this occurs, remove the AC plug.
4. How to Change to Servo Standby Mode
After activating the test mode, press the “STOP” button to change to Servo Standby mode.
Various modes are able to switch from this mode (display shows “ALL SV OFF”).
Press the “STOP” button in each mode operation to return to “ALL SV OFF” that is returns to the original display.
5. Sled Feed Operation Check
In “ALL SV OFF”, press the “B.SKIP” or “F.SKIP” button to move the lens and PICK UP to outer or inner track respectively.
PICK UP moves to the inner most track and the “JAZZ” lights up when “INSIDE LIMIT SW” is pressed.
* Make sure that checking is in loading mode because the range of movement allowable for PICK UP is restricted when unloading.
PICK UP moves to outer track. PICK UP moves to inner track

– 9 –
6. Laser Power Check
1) IN “ALL SV OFF”, laser power status changes each time the “MD EDIT/REC” button is pressed. The display changes as shown in the
following diagrams.
“ALL SV OFF”: Laser Off
“LASER READ”: Laser Read Power (approximately 0.68mW)
“ LASER 1/2”: Laser 1/2 Read Power (approximately 0.34mW)
“LASER WRITE”: Laser Write Power (approximately 6.8mW)
2) After checking, press “STOP” or “MD EDIT/REC” button to return to “ALL SV OFF” display.
7. Loading Mechanism Operation and Detection Switch Check
7-1 Loading Mechanism Operation Check
In “ALL SV OFF”, insert the MO DISC, press the “NORMAL” button of CD MD SYNC REC or “MD EJECT” button to UP/DOWN
the OWH.
CD MD SYNC REC “NORMAL” button: OWH DOWN (during loading)
“MD EJECT” button: OWH UP (during loading)/unloading
There is no change in the display.
* Cautions: 1) When a pre-mastered disc such as test disc (TGYS-1) or soft disc is inserted, do not press DOWN for OWH.
2) When unloading, do not press the “CD MD SYNCHRO REC NORMAL” button. Damage may be occurred.
7-2 Detection Switch Check
REFLECT SW, REC PROTECT SW, INSIDE LIMIT SW, Disc Mode (PIT, MO) selections will be shown on the display.
“JAZZ” is lit: INSIDE LIMIT SW is turned on.
PICK-UP is in inner most track position.
“POP” is lit : REFLECT SW is turned on.
When a high reflectivity DISC is inserted (such as TEST DISC).
“ROCK” is lit: REC PROTECT SW is turned on.
When MO DISC is inserted (REC PROTECT).
“TIME MARK” is lit: DISC MODE PIT selection.
“AUTO MARK” is lit: DISC MODE GRV selection.
8. Servo Operation Check
8-1 Focus Search/Spindle Kick Check 1
1) In “ALL SV OFF” with no DISC inserted, press the “PLAY” button to change to focus search and spindle kick modes. “FOCUS SRCH”
appears on the display.
2) After the checking, press “STOP” button to return to “ALL SV OFF” display.

– 10 –
8-2 Focus Search/Spindle Kick Check 2 (S curve check)
1) In “ALL SV OFF”, press the “BAND” button on tuner section to change to focus search and spindle kick modes. At this time, “FOCUS
CHECK” appears on the display. This mode can operate repeatedly regardless of DISC existence and S curve can be checked with DISC in
this mode.
2) After checking, press the “STOP” button to return to “ALL SV OFF” display.
8-3 Focus Servo and Sled Error (EF Balance) Check
1) Insert the DISC.
2) Press the “MD MODE” button to choose the DISC mode as shown in the following.
• PIT DISC: Display shows “SELECT PIT” • MO DISC: Display shows “SELECT GRV”
3) Press the “PLAY” button.
During normal focus search, the display shows “FOCUS SRCH” followed by “FOCUS ON!” which indicates that focus search is turned on.
4) In “FOCUS ON!”, press the “DISPLAY” button on tuner section to show “S.ERR = **” on the display. This mode can check on DC offset of
EF balance.
S.ERR: Sled Error (EF balance, DC offset)
It is normal if it changes in a range of 70-89 where 80 is the centre.
5) After checking, press the “STOP” button to return to “ALL SV OFF” display.
8-4 All Servo On Check
1) In “FOCUS ON!” mode, press the “ENTER” button on amp section to turn on tracking sled servo and all the servo are activated.
If all the servo are normal, the display will show “ALL SV ON”.
2) After checking, press the “STOP” button to return to “ALL SV OFF” display.

– 11 –
9. Address, Error Rate Check
1) In “ALL SV ON” mode, press the “DISPLAY” button on tuner section to check for the address and error rate.
Address Display: displays the address read by All Servo On
Error Rate Display: displays the 4 digits on the left as error rate
(digits below 0030 is normal)
Focus Bias: Fixed at “FBIAS = 00”
2) Refer to the adjustment section for checking the recording/playback error.
10. How to Erase U-TOC (User TOC)
Make the DISC that appears on display from “U-TOC ERROR” to “BLANK DISC”.
1) Insert the MO DISC.
2) Press the “MD MODE” button to change the display to “SELECT GRV”.
3) Move the PICK UP to the centre position of the DISC with “B.SKIP” or “F.SKIP” button.
4) Press the “PLAY” button to change the display to “FOCUS ON!”.
5) Press the “ENTER” button on the AMP section to change the display to “ALL SV ON”
6) Press the “JOG MODE” button on the AMP section and the display becomes “UTOC ERASE”.
7) U-TOC is erased when “ALL SV OFF” appears on the display.

– 12 –
MD Electrical Adjustment
Perform all MD block adjustments and checking in test mode.
When “NO ADJUST” appears on the display, perform all the adjustments.
Measuring Device and Tools
Attached Remote Controller
Temperature indicator (Degree Celsius), Laser Power meter (available to measure up to 10mW)
Test DISC: TGYS-1 or TDYS-1 (or soft disc), MDW-74 (or similar product)
Before Adjustment
Use a DISC that is not scratched or contaminated for the adjustment.
(The adjustment may not be able to be performed if the DISC is scratched or contaminated.)
During adjustment, do not reverse the MD mechanism or place it in a slanting position.
Adjustment Procedure
All the adjustment procedures are listed in the flow chart below.
Follow 1 to 7 of the flow chart for the adjustment procedure.
Adjustment Procedure
START
1Activate TEST MODE
2EEPROM Initialisation
3Temperature Compensation
Adjustment
4Laser Power Check
5AUTO SEQUENCE ADJ
6Error Rate Check
7After Adjustment Check
END
About the mark in the procedure
Show button operation.
ELECTRICAL ADJUSTMENT

– 13 –
START
1Activate TEST MODE
Press and hold the “PLAY”
button on the MD section and
insert the AC plug into the outlet.
2EEPROM Initialisation
“OPEN/CLOSE” the CD section
“STOP”
To next step
Adjustment Procedure Flow Chart

– 14 –
3Temperature Compensation
Adjustment
“DISPLAY” on TUNER section
“PAUSE”
Temperature Compensation Adjustment
Importance of this adjustment is
that board temperature and room
temperature are the same.
Using the temperature indicator (Degree Celsius), compare
the surrounding temperature of the MD mechanism
measured on the display with the temperature indicator,
(temperature indicator displays – 3 degree celsius) =
display temperature of this unit.
“ENTER” of AMP section
“STOP”
To next step
“B.SKIP” “K.SKIP”

– 15 –
Write Power Check
Press “MD EDIT/REC” twice.
“PAUSE”
Write Power Setup Value Check
Check that “LASER= 89” is displayed
“ENTER” on AMP section
Write Power Check
Measure with the Laser Power Meter
Check: Laser Output is approximately
6.80mW
“STOP”
To next step
4Laser Power Check
Read Power Check
“MD EDIT/REC”
“PAUSE”
Read Power Setup Value Check
Check that “LASER= OF” is displayed
“ENTER” on AMP section
Read Power Check
Measure with the Laser Power Meter
Check: Laser Output is approximately
0.68mW

– 16 –
MO DISC Adjustment Value Check
“PLAY”
“ENTER” on AMP section
“STOP”
Press “DISPLAY” on TUNER section twice
Adjustment Value Check (IVR, EF balance)
“DISPLAY” on TUNER section
Adjustment Value Check
(Focus / Tracking / Sled Gain)
“STOP”
“MD EJECT”
Take out the DISC
To next step
5AUTO SEQUENCE ADJ
MO DISC Adjustment
MDW-74 (or similar product) Loading
“MD MODE”
AUTO MARK is lit
Remote Controller “MD” function
This display indicates that the
adjustment cannot be performed.
IVR Value Check
04-0A (Hexadecimal)
EF Balance Value Check
09-15 (Hexadecimal)
Focus Gain Value Check
1A - 50 (Hexadecimal)
Tracking Gain Value Check
0C - 30 (Hexadecimal)
Sled Gain Value Check
0C - 30 (Hexadecimal)

– 17 –
5AUTO SEQUENCE ADJ (continued)
PIT DISC Adjustment
TGYS-1 or TDYS-1 loading
“MD MODE”
“TIME MARK” is lit
Remote Controller “MD” function
This display indicates that the
adjustment cannot be performed.
PIT DISC Adjustment Value Check
“STOP”
Press “DISPLAY” on TUNER section twice
Adjustment Value Check (IVR, EF balance)
“DISPLAY” on TUNER section
Adjustment Value Check
(Focus/Tracking/Sled Gain)
“STOP”
“MD EJECT”
Take out the DISC
To next step
EF Balance Value Check
09-15 (Hexadecimal)
Sled Gain Value Check
0C-3F (Hexadecimal)
IVR Value Check
14-19 (Hexadecimal)
Focus Gain Value Check
1A-50 (Hexadecimal)
Tracking Gain Value Check
0C-3F (Hexadecimal)

– 18 –
Address Display
“DISPLAY” on TUNER section
Playback Error Check
Below 0030
“STOP”
“MD EJECT”
Take out the DISC
To next step
6Error Rate Check
Playback Error Rate Check
TGYS-1 or TDYS-1 Loading
“MD MODE”
“TIME MARK” is lit
“B.SKIP” “F.SKIP”
PICK UP moves to the centre position of DISC
Remote Controller “AUX” function

– 19 –
6Error Rate Check (continued)
Recording/Playback Error Rate Check
MDW-74 (or similar product) loading
“B.SKIP” “F.SKIP”
PICK UP moves to the centre position of DISC
“PLAY” on CD section
Address display
Automatically begins recording from 600C
Records for approximately 15 - 30 seconds
“STOP”
Remote Controller “AUX” function
“DISPLAY” on TUNER section
once 600C is exceeded
Record Error Check
Below 0030
“STOP”
“MD EJECT”
Take out the DISC
To next step

– 20 –
7After Adjustment Check
Press “POWER” twice and check that “NO
ADJUST” is not displayed when the power
is switched on.
END