Daewoo AKF-0275 Series User manual

Service Manual
Car Audio Basic, RDS & OIRT Band
S/M No:AKF0275EF0
MODEL : AKF-0275 Series
AKF-0285 Series
DAEWOO ELECTRONICS CO., LTD
http://svc.dwe.co.kr Jan. 2000
4-Channel High Power (35W x 4Ch)
Electronic Tuning
Electronic
Volume /Bass /Treble /Balance /Fader Controls
Auto Memory/Preset Scan
Repeat/Random/Intro Scan
Local/DX Switch
Loudness & Mute Controls
Flip-Down Detachable Face for Anti-Theft

TABLE OF CONTENTS
1. PRODUCT SPECIFICATIONS ..................................1
2. LINE DRAWING .............................................2
3. ADJUSTMENTS ...........................................5
4. SCHEMATIC DIAGRAM ..................................10
5. PARTS LOCATION ON P.C. BOARD .............................13
6. OVERALL EXPLODED VIEW & PARTS LIST ....................15
7. DECK MECHANISM EXPLODED VIEW & PARTS LIST .......17
8. PARTS LIST .............................................20
9. FUNCTION OF MICOM IC ..................................22
10. IC BLOCK DIAGRAM ..................................28
11. LIQUID CRYSTAL DISPLAY .............................32
12. OUTPUT CONNECTION DESCRIPTIONS ....................34

- 1 -
1. PRODUCT SPECIFICATIONS
1-1. TECHNICAL SPECIFICATION
Power requirements : DC 12.0V / Rated : 14.4V
(Usable : 10.8 15.6V)
Negative ground
Current consumption : 10A Maximum
Dimension (W x H xD) : Body 178 x 50 x 165 mm
: Escutcheon 188 x 58 x 15 mm
Weight (Net) : 2.7 kg
Design and specifications are subject to change for improvements without notice.
AUDIO SECTION
Maximum output power : 35watts per channel into 4 ohms.
Load impedance : 4 ohms
Total harmonic distortion : Less than 10% at 12 watts
Frequency response : 100Hz( +3
dB ), 10kHz(-5 +3 dB )
TAPE SECTION
Track format : 2-track / 2-channel system
Tape speed : 4.75cm/sec
Wow / Flutter : 0.35% max. (WRMS)
Signal to Noise ratio : More than 50
dB
Channel Separation : More than 35 dB
Frequency response normal (LH)tape : 63Hz to 10kHz ( + 3 dB )
TUNER SECTION
(FM) Tuning range : 87.5 to 108MHz
87.5 to 107.9 at U.S.A
Usable Sensitivity(MONO) : 10
dB
u (4uV/75ohms)
Stereo Separation : 30
dB
Signal to noise ratio (at 60dBu) : More than 50 dB
(MW) Tuning range : 522 to 1620kHz at Europe
530 to 1710kHz at U.S.A
Usable Sensitivity : 28
dB u
(LW) Tuning range (*option) : 144 to 288kHz
Usable Sensitivity : 40
dB u
1-2. GENERAL SPECIFICATION

2. LINE DRAWING
WITHOUT RDS FUNCTION : BASIC
WITH RDS FUNCTION : RDS
2-1. AKF-0275 FRONT SIDE
- 2 -

LINE DRAWING
2-2. AKF-0285 FRONT SIDE
- 3 -
WITHOUT RDS FUNCTION : BASIC
WITH RDS FUNCTION : RDS

LINE DRAWING
- 4 -
2-3. AKF-0275/AKF-0285 REAR SIDE

3. ADJUSTMENTS
- 5 -
3-1. CONNECTIONS EQUIPMENTS

ADJUSTMENTS
3-2. ADJUSTMENT LOCATIONS IN TUNER MODULES
- 6 -

ADJUSTMENTS
3-3. AM (MW/LW) ADJUSTMENT
- 7 -
STEP
1 Band Covering
RF-Tracking
Figure 1
Figure 2
Figure 2
Figure 1
Figure 2
522KHz 60dBu
Mod 1000Hz 30%
603KHz 30dBu
Mod 1000Hz 30%
1404KHz 30dBu
Mod 1000Hz 30%
144KHz 60dBu
Mod 1000Hz 30%
220KHz 60dBu
Mod 1000Hz 30%
522KHz
603KHz
1404KHz
144KHz
220KHz
Adjust AM OSC
for 1.2-1.35V(VT)
Fig.8
Adjust AM RF1 and
AM RF2
for maximum output
Fig.8
Adjust AM RF1 and
AM RF2
for maximum output
Fig.8
Adjust LW OSC
for 1.2-1.35V(VT)
Fig.8
Adjust LW RF1 and
LW RF2
for maximum output
Fig.8
RF-Tracking
LW Band Covering
LW-Tracking
2
3
4
5
DESCRIPTION CONNECTION ANTENNA SIGNAL
DIAL
CONTROL ADJUSTMENT
1. Dummy Antenna Circuit
2. Location of Adjustment Points
Refer to Adjustment Location Page
3. Control Setting
Power Switch
............. ON Balance/Fader Control ................ Mech. Center
Band Switch .............. AM Treble/Bass Control ................... Mech. Center
Other ...................... OFF
4. Adjustment Procedure
NOTE: When it is U.S.A band instead of 522, 603, 999, 1404kHz is 530, 600, 1000, 1400kHz

ADJUSTMENTS
3-4. FM ADJUSTMENT
- 8 -
STEP
1 IF (Zero Volt)
RDS Receiving
estimation level
Figure 3
Figure 4
Figure 5
Figure 5
98.1MHz 60dBuV
No Modulation
98.1MHz 42dBuV
Mod.
1kHz 30% Mono
98.1MHz 60dBuV
Mod.
1kHz 30% Stereo Left
at Right ch.
98.1MHz 35dBuV
Mod.
1kHz 30% Stereo Left
at Right ch.
98.1MHz
98.1MHz
98.1MHz
98.1MHz
Adjust FM DET
for 0V +0.03V
Fig.8
Adjust RV 101 Tuner PC
Board for2.7V=20mV at
TP102(IC401 pin 66)
Adjust MPX SEP Fig.8
for maximum separation
Left and Right ch.
Adjust Stereo Blend
Fig.8 1dB separation
between Left and Right
ch.
Stereo Separation
SNC
4
5
6
DESCRIPTION CONNECTION ANTENNA SIGNAL
DIAL
CONTROL
ADJUSTMENT
1. Dummy Antenna Circuit
2. Location of Adjustment Points
Refer to Adjustment Location Page
3. Control Setting
Power Switch
............. ON Balance/Fader Control ................ Mech. Center
Band Switch ............... FM Treble/Bass Control .................. Mech. Center
Other ...................... OFF
4. Adjustment Procedure

ADJUSTMENTS
3-5. TAPE ADJUSTMENT
NOTE : 1. Clean the playback head before adjustment
2. Prepare the test tape MTT-144 or equivalent
3. Balance, Fader, Bass & Treble ....Center position. Volume adjusted to 2Volts.
Note : dBu uV dBuV uV
17 5.0 33 44.6
16 6.31 35 56.2
30 31.6 45 178
NOTE : Antenna signal is used.
1. For Signal Generator with readings in
EMF(Open type) add 12dB (6dB for the
“Dummy” and 6dB for EMF-reading).
2. For Signal Generator with reading in dBm add 6
dB for “Dummy”
STEP
1Head azimuth
adjustment
Tape Speed
Figure 6
Figure 6
MTT-144N
or equivalent
MTT-144N
or equivalent
Speaker
Output
Speaker
Output
Head azimuth
adjustment screw
Turn the azimuth
screw to obtain
maximum level
Adjust for 3010-
3020Hz
Tape Speed
adjustment
2
DESCRIPTION TEST TAPE CONNECTION
TEST
POINT
ADJUSTMENT
POINT ADJUSTMENT
- 9 -

4. SCHEMATIC DIAGRAM
4-1. BASIC Series AKF-0275/0285
- 10 -
Size:A3

SCHEMATIC DIAGRAM
- 11 -
4-2. RDS Series AKF-0275/0285
Size:A3

SCHEMATIC DIAGRAM
- 12 -
4-3. OIRT Band AKF-0275/0285
Size:A3

5. PARTS LOCATION ON P.C. BOARD
PCB MAIN : AKF-0275/0285 Series
PARTS SIDE
- 13 -

PARTS LOCATION ON P.C. BOARD
BOTTOM SIDE
- 14 -

6. OVERALL EXPLODED VIEW & PARTS LIST
- 15 -
6-1. AKF-0275 BASIC & RDS
Size:A3

OVERALL EXPLODED VIEW & PARTS LIST
- 16 -
6-2. AKF-0285 BASIC & RDS
Size:A3

7. DECK MECHANISM EXPLODED VIEW & PARTS LIST
EXPLODED VIEW
- 17 -

DECK MECHANISM EXPLODED VIEW & PARTS LIST
- 18 -
PARTS LIST
No PART CODE
97YM002600
97YM002900
97Y0900800
97Y2100400
97Y2101000
97Y0900200
97Y8000300
97Y6400100
97YM003200
97Y3000400
97YM003100
97Y3000300
97Y2700400
97Y2700800
97Y2100500
97Y8100200
WP-7021563
97Y2700700
97Y2400200
97Y2700900
97YM003400
97YM003500
97Y2101400
97Y3000800
97Y3700100
97Y3000900
97Y2700600
97Y2900200
97Y4100100
97Y2700500
97Y3000600
97Y3100100
97Y4000100
97Y3000500
97Y0400100
97Y2101500
97Y2701200
PART NAME
CHASSIS MAIN SUB AS
LEVER GEAR LOAD AS
PLATE REVERSE
ARM EJ CAM
ARM TAPE SELECT
PLATE HEAD
HEAD AS
TERMINAL EARTH
ARM PINCH R AS
SPRING PINCH ARM (R)
ARM PINCH F AS
SPRING PINCH ARM (F)
GEAR REDUCTION
GEAR WORM WHEEL
ARM IN SW
MOTOR SUB
WIRE RIBBON
GEAR WORM
BRACKET MOTOR
CAM EJECT
BRACKET L AS
ARM TAPE CATCH A AS
ARM TAPE CATCH (B)
SPRING TAPE CATCH ARM
PULLEY IDLE
SPRING TU ARM
GEAR TU
REEL SPINDLE
FELT REEL
GEAR REEL
SPRING REEL
WASHER REEL
BUSHING REEL
SPRING REEL CAP
CAP REEL
ARM DETECT GEAR
GEAR DETECT
DESCRIPTION
ADM-22 FULL LOGIC DECK
ADM-22 FULL LOGIC DECK
SUS-304 1/2H T0.4
EGSAFC45R T0.8
EGSAFC45R T0.8
EGSAFC45R T0.8
HEAD+FPC
ET T0.2
ADM-22 FULL LOGIC DECK
SWP-B PI0.65 TORS
ADM-22 FULL LOGIC DECK
SWP-B PI0.65 TORS
POM DURACON M90-44 (N)
POM DURACON OL-10 (N)
EGSAFC45R T0.8
FF-050SH-11190
AWG28 2P
POM DURACON M90-44 (N)
EGSAFC45R T0.8
EGSAFC45R T0.8
ADM-22 FULL LOGIC DECK
ADM-22 FULL LOGIC DECK
EGSAFC45R T0.8
SWP-B PI0.65 EXTN
POM DURACON ES-5
SUS-403WPB PI0.2 EXTN
POM DURACON OL-10 (N)
POM DELRIN-500 (N)
FELT PI5.6XPI18XT0.8
POM DELRIN-500 (N)
SUS-304WPB PI0.7 CONE
PS PI4.0XPI18.0XT0.4
POM DURACON M90-44 (N)
SUS-304WPB PI0.3 COMP
POM DURACON M90-44 (N)
POM DURACON M90-44 (N)
POM DURACON M90-44 (BK)
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ADM-22