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FILE NO.
Service Manual
Micro Component System
DC-DA370 (UK)
PRODUCT CODE No.
129 599 00
REFERENCE No.
SM5810201
This service manual consists of "DC-DA370U" (Main unit : 129 598 00) and "SX-DA370"
(Speaker system : 165 027 00).
Contents
Specifications ................................................................... 1
System connection ........................................................... 1
Laser beam safety precaution .......................................... 2
CD pick-up maintenance .................................................. 2
CD player adjustments ..................................................... 2
Tape adjustments ............................................................ 3
Tuner adjustments ........................................................... 4
What to do if ..................................................................... 5
When assembling the Rack Gear and CD Lid ................. 5
When replacing LED (D6310) .......................................... 5
Exploded view
(Cabinet & Chassis) ...................................................... 6
(Tape mechanism) ........................................................ 11
Parts list
(Cabinet & Chassis) ...................................................... 7
(CD mechanism) ........................................................... 7
(Tape mechanism) ........................................................ 11
IC block diagram & description ........................................ 11
LCD display description ................................................... 15
Schematic diagram
(CD) ............................................................................... 16
(FRONT) ....................................................................... 18
(AMPLIFIER ) ................................................................ 24
(TUNER) ....................................................................... 26
Wiring diagram
(CD & FRONT) .............................................................. 20
(TUNER & AMPLIFIER ) ............................................... 22
(PRIMARY + SECONDARY POWER
TRANSFORMER AND CD LID SWITCH) .................... 28
Voltage Table ................................................................... 29
Wiring connection ............................................................ 31


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- 1 -
SPECIFICATIONS
General
Output power ......................... 12.5 W x 2
(at 4 ohms, 10% distortion)
Inputs ..................................... VIDEO IN : 400 mV / 50k ohms
Outputs .................................. SPEAKERS : 4 ohms
PHONES : 8 - 32 ohms
OPTICAL OUT:Optical
Power requirements ............... AC 230V, 50Hz
Power consumption ............... 40 W
Dimensions (W x H x D) ........ Approx. 160 x 251 x 207 mm
Weight .................................... Approx. 3.2 kg
Speaker system
Type ....................................... 3 way bass reflex
Unit used : Woofer ................. 10 cm cone type
: Mid range ............. 5 cm cone type
: Tweeter ................ 2 cm piezoelectric
Maximum
power-handling capacity ..... 25 Watts (peak)
Nominal impedance ............... 4 ohms
Dimensions (W x H x D) ........ Approx. 150 x 245 x 224 mm
Weight .................................... Approx. 1.9 kg (per speaker)
Specifications subject to change without notice.
Tuner
Reception frequency .............. FM : 87.5 - 108.0 MHz
MW: 522 - 1611kHz
LW : 144 - 288kHz
CD player
Channels ................................ 2-channel stereo
Sampling frequency ............... 44.1 kHz
Pick-up ................................... Optical 3-beam
semiconductor laser
Wow and Flutter ..................... Below measurable limits
Wave length ........................... 790 nm
Laser output ........................... 0.6mW(Continuous wave max.)
Cassette deck section
Track system ......................... 4-track, 2-channel stereo
Frequency response .............. 60 Hz - 13.5 kHz
Signal to noise ratio ............... 50 dB
Wow and Flutter ..................... 0.12% (WRMS)
Fast forward / Rewind time .... Approx. 110 sec. (C-60)
SYSTEM CONNECTIONS
Video/Auxiliary equipment
External aerial
AM loop aerial
Aerial wire
Digital equipment
R ch speaker
L ch speaker
Amplified Subwoofer
To an AC outlet


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- 2 -
LASER BEAM SAFETY PRECAUTION
· Pick-up that emits a laser beam is used in this CD player section.
CAUTION :
USE OF CONTROLS OR ADJUSTMENTS
OR PERFORMANCE OF PROCEDURES
OTHER THAN THOSE SPECIFIED HEREIN
MAY RESULT IN HAZARDOUS RADIATION
EXPOSURE
LASER OUTPUT .......... 0.6 mW Max. (CW)
WAVELENGTH ............. 790 nm
CAUTION ­ INVISIBLE LASER RADIATION WHEN OPEN AND
INTERLOCKS DEFEATED. AVOID EXPOSURE TO BEAM.
ADVARSEL ­ USYNLIG LASER STRÅLING VED ÅBNING, NÅR
SIKKERHEDSAFBRYDERE ER UDE AF FUNKTION, UNDGÅ UDS ÆTTELSE
FOR STRÅLING.
VARNING ­ OSYNLIG LASER STRÅLNING NÄR DENNA DEL ÄR ÖPPNAD
OCH SPÄRR ÄR URKOPPLAD. STRÅLEN ÄR FARLIG.
VORSICHT ­ UNSICHTBARE LASERSTRAHLUNG TRITT AUS, WENN
DECKEL GEÖFFNET UND WENN SICHERHEITSVERRIEGELUNG
ÜBERBRÜCKT IST. NICHT, DEM STRAHL AUSSETZEN.
VARO ­ AVATTAESSA JA SUOJALUKITUS OHITETTAESSA OLET ALTTIINA
NÄKYMÄTTÖMÄLLE LASERSÄTEILYLLE. ÄLÄ KATSO SÄTEESEEN.
CD PICK-UP MAINTENANCE
About pick-up (Optical lens) Cleaning
Clean a lens with swab of the cotton which moistened it with alcohol, cleaning paper or cleaning disc appointed.
Specified cleaning disc : LC-1 (Part code : 645 026 1961 ..... manufactured by SANYO.)
Show a clean procedure in the following in reference by swab of cotton.
1. Cotton swab is wrapped with Cleaning paper.
2. Add the isopropyl alcohol.
3. Gently move the tip of cotton swab just like a draw a whirlpool from inside to outside on the surface of lens.
CD PLAYER ADJUSTMENTS
1. ADJUSTMENTS
(1) Confirm the tracking balance
1. Turn on the POWER switch.
2. Connect an Oscilloscope to TP2 (TE) and TP4 (VC).
3. Set the test disc.
4. Press "PLAY" button to turn into the "PLAY" mode.
5. Keep holding "SKIP" button down so as to be "SERCH"
mode, then confirm that the oscilloscope waveform is
symmetrical on the top and bottom in relation to 0V (VC).
200mV/div.
5ms/div.


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- 3 -
OPENING EXPANDED
b
a
(2) Checking the "eye" pattern
1. Switch "ON" the POWER.
2. Connect an oscilloscope to TP1 (RF) and TP4 (VC).
3. Load the test disc.
4. Press the PLAY button.
5. Check to be sure that the "eye" pattern is at the center of
waveform and that the diamond shape is clearly defined.
6. Press the STOP button.
7. Turn off the POWER switch.
CD PLAYER ADJUSTMENTS
OSCILLOSCOPE
+
TP1
(RF)
TP4
(VC)
-
TAPE ADJUSTMENTS
· Be sure to clean the heads before attempting to make any adjustment.
· Be sure both channels (1 and 2) are the same level.
(Using a dual-channel oscilloscope)
· Be sure both channel's waveform are same for the phase matching.
· After completion of the adjustment, use the threadlock (TB-1401B) to
secure the azimuth adjustment screws.
1. Remove the cover deck as Fig.1.
2. Load a test tape (VTT-738 etc. : 10kHz) in the Deck.
3. Press the PLAY button. (Normal playback)
4. Use a + tip screwdriver to turn the screw for normal azimuth
adjustment so that the left and right outputs are maximized at
the same phase during normal playback. See Fig.2.
5. Press the PLAY button. (Reverse playback)
6. Use a + tip screwdriver to turn the screw for reverse azimuth
adjustment so that the left and right outputs are maximized
at the same phase during reverse playback.
7. Adjust so that the waveforms for the left and right channels are in alignment.
1. Azimuth Adjustment
3. Torque Measurement
2. Tape Speed Adjustment
Test Cassette
Take-up Torque
Back tention
Driving power cassette :
TW-2412 (PLAY)
TW-2422(REV. PLAY)
70 ~140 grcm
PLAY/REV.
F.FWD
REW
2 ~ 6 grcm
-
-
70 ~ 140 grcm
Pulley tention
Item
PLAY : TW2111A (FWD)
PLAY : TW2121A (REV)
F.FWD / REW : TW2231
PLAY : TW2111A (FWD)
PLAY : TW2121A (REV)
30 ~ 65 grcm
30 ~ 65 grcm
· Connect the Frequency Counter to TAPE OUT.
1. Insert the test tape (MTT-111N, etc.; 3,000Hz) into the DECK.
2. Press the PLAY button. .
3. Adjust a hole on the motor bottom so that a frequency counter reading of 3,000
5Hz is obtained.See Fig.3.
4. Press the STOP button, and eject the test tape.
Fig.1
Fig.2
50grcm
hole for adjustment
MOTOR
Fig.3
REVERSE
NORMAL


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TUNER ADJUSTMENTS
1. FM
Step Adjusting
Connection
SG
Set
Adjustment
Remark
Circuit
Input
Output
Frequency Position
1
98.0MHz.Input Level
Alignment voltage IC231
Alignment voltage IC231
FM Antenna SG=66dBÊV
3-22pin(TP24,25) is 0.0·} 0.05V
3-22pin is 0.0·} 0.5V
2
Cover
---
Connect Digital DC voltmeter to
87.5MHZ
Low
---
1.4·} 0.05V
Voltage
---
TP11(H), TP12(E).
108.0MHZ
High
---
6.8·} 0.5V
2. MW
Step Adjusting
Connection
SG
Set
Adjustment
Remark
Circuit
Input
Output
Frequency Position
1
Connect Sweep generator to test
450kHz
point TP13(L)or TP14(R) and TP15(E). (at 999kHz)
2
Cover
---
Connect Digital DC voltmeter to
522kHZ
Low
1.00·} 0.05V
Voltage
---
TP11(H )and TP12(E).
1611kHZ
High
6.70·} 0.10V
3
Tracking Connect AM SG to
Connect to VTVM
603KHZ
Low
L2151
Test loop Ant.
point TP13(L)or TP14(R) and TP15(E).
1404kHZ
High
CT252
3. LW
Step Adjusting
Connection
SG
Set
Adjustment
Remark
Circuit
Input
Output
Frequency Position
1
Cover
---
Connect Digital DC voltmeter to
144kHZ
Low
L2154
1.00·} 0.05V
Voltage
---
TP11(H) and TP12(E).
288kHZ
High
---
5.42·} 0.10V
2
Tracking Connect AM SG to
Connect to VTVM
162kHZ
Low
L2152
Test loop Ant.
point TP13(L)or TP14(R) and TP15(E).
279kHZ
High
CT251
IF(0V)
Adjustmen
Low
XF233
AF Maximum
98MHz
AF Maximum
IF
Low
T2002
AF Maximum
---
L2153
Standatd Input: 60dB
Antenna
: 75 unbalanced , Modulation : 1 kHz
Dev.
: ·} 22.5kHz(MONO) [email protected](STEREO) ·} 6.75kHz(PILOT)
SG Modulation
: 1kHz, 30%
Antenna, IRE Loop, Distance : 60 cm
· Use a plastic screw driver for adjustments.
· MODE : ST (Stereo)
· Speaker impedance : 4 ohm
· TUNING
FM : 87.5 - 108MHz
MW: 522 - 1611kHz
LW : 144 - 288kHz