Daewoo AKF-8825 series User manual

Service Manual
Car Audio Basic, RDS
S/M No : AKF8825EF0
MODEL : AKF-3825 Series
AKF-8825 Series
DAEWOO ELECTRONICS CO., LTD
http://svc.dwe.co.kr Apr. 2000
PARTIAL DETACHABLE
LOW POWER (7W x 2 or 4CH)
REMOTE CONTROL
AUTO STOP or REVERSE DECK MECHANISM
ELECTRONIC VOLUME CONTROL
LOUDNESS
LOCAL / DX

TABLE OF CONTENTS
1. PRODUCT SPECIFICATIONS ..................................................1
2. LINE DRAWING ........................................................................2
3. EMERGENCY TROUBLE SHOOT ............................................4
4. ADJUSTMENTS ........................................................................7
5. SCHEMATIC DIAGRAM ..........................................................12
6. PARTS LOCATION ON P.C.BOARD ......................................15
7. OVERALL EXPLODED VIEW & PARTS LIST .......................19
8. DECK MECHANISM EXPLODED VIEW & PARTS LIST .......21
9. PARTS LIST ............................................................................27
10. FUNCTION OF MICOM IC .....................................................31
11. IC BLOCK DIAGRAM .............................................................37
12. LIQUID CRYSTAL DISPLAY ..................................................42
13. OUTPUT CONNECTION DESCRIPTIONS ............................43

1
1. PRODUCT SPECIFICATIONS
AUDIO SECTION
Maximum output power : 7watts per channel into 4 ohms.
Load impedance : 4 ohms
Total harmonic distortion : Less than 10% at 5 watts
Frequenc response : 100Hz( + 3dB), 10kHz(-5 + 3dB)
Control Bass/Treble : 10 + 3dB at 100Hz/10kHz
TAPE SECTION
Track format : 2-track / 2-channel s stem
Tape speed : 4.75cm/sec
Wow / Flutter : 0.35%max. (WRMS)
Frequenc response normal (LH)tape : 63Hz to 10kHz
TUNER SECTION
(FM) Tuning range : 87.5 to 108MHz
87.5 to 107.9 at U.S.A
Usable Sensitivit (MONO) : 12dBuV(4
uV / 75ohms)
Signal to noise ratio (at 60dBu)
: More than 50dB
(MW) Tuning range : 522 to 1620kHz at Europe
530 to 1710kHz at U.S.A
Usable Sensitivit : 30dBuV
GENERAL
Power requirements : DC 12.0V / Rated : 14.4V
(Usable : 10.8 ~15.6V)
Negative ground
Current consumption : 3A Maximum
Dimension (W x H x D) : 178 x 50 x 160.5 mm
Weight(Net) : 1.1 kg (AKF-3825) / 1.25Kg (AKF-8825R)
Design and specifications are subject to changes for improvements without notice.

2
2. LINE DRAWING
2-1. FRONT SIDE
AKF-3825 BASIC
AKF-8825 BASIC
AKF-8825 RDS
- Partial detachable
- 2 x 7W
- Remote control
- Auto stop deck mechanism
- Electronic volume control
- Loudness
- Local / DX
- Partial detachable
- 2 x 7W
- Remote control
- Auto reverse
- Electronic volume control
- Loudness
- Local / DX
- Partial detachable
- 4 x 7W
- RDS (AF, PTY, EON, TA)
- Auto reverse deck mechanism
- Remote control
- Electronic volume control
- Loudness
- Local / DX

3
LINE DRAWING
2-2. REAR SIDE

4
3. EMERGENCY TROUBLE SHOOT
3-1. General Function
No sound from
speakers
Yes
No
Yes
Output connector
is missing
Output connector
is inferior goods
Put exactl output
connector in.
Change output
connector to
superior goods
Yes
No
Power IC, Output
Socket is inferior
goods
Change Power IC,
Output Socket to
superior goods
Yes
A
A
L.C.D or L.E.D
is not turned
off.
Yes
No
Yes
Power is not
supplied Ref. Point
Output voltage of
power IC is little.
Change Regulator
IC and check
output voltage.
Yes
No
LCD or LED is
inferior goods.
Change LCD or
LED to superior
goods.
Yes
Different each
channel have
output level
(Front Rear
Left Right)
Treble or Bass
is low
unusually
Yes
No
Yes
Balance of front
and rear is in one
side
Balance of Left,
Right is in one
side.
Re-adjust Balance
of front, rear
Ref.
Balance = Center
Front:00 / Rear:00
Ref.
Balance = Center
Left:00 / Right:00
Ref.
Balance = Center
Treble:00 / Bass:00
Ref.
Regulator IC output
Voltage = V
Ref.
Electrical Parts List
L.C.D., L.E.D.
Re-adjust Balance
of Left, Right
Yes
Yes
Balance of Treble
or Bass is in one
side.
Re-adjust Balance
of Treble or Bass
Yes

5
EMERGENCY TROUBLE SHOOT
3-2. Tuner Function
Hearing noise
only
Yes
No
Yes
No selected the
station
Tuner Module is
inferior goods.
Select exactl
broadcasting
frequenc .
Change tuner
module to
superior goods.
Yes
Weak frequenc
area caused b
elevations
Change to goods of
R.D.S function.
Yes
A
B
A
Station in
other regions
are not held.
Yes Yes
No selected the
local stations. Ref. Point or
Extreme noise
in broadcast
Weak
separation of
FM stereo
Yes
No
Yes
Antenna
connector is
missing
Put exactl
antenna connector
in his jack
Ref.
CAT-8, KCC-654V
Electrical Parts List
Function of auto-
switch noise
reduction
Ref.
Yes
Weak frequenc
area of FM, AM
Switch
automaticall to
mono mode in
weak frequenc
area
Yes
B
R1 In case of located Glass Antenna, check if heat wire is cut or not in rear window.
R2 Check Antenna connector part.

6
EMERGENCY TROUBLE SHOOT
3-3. Tape Function
No sound from
speakers
Yes
No
Yes
Tape is inferior
goods
No signal pla
output
Use onl superior
goods
Put exactl deck
output connector
in.
Yes
No
Deck Mechanism
is inferior goods.
Change Deck
Mechanism to
superior goods.
Yes
A
A
Sound is low or
not clear
Yes Yes
Head is dirt
Ref. Point
Clean head or
pinch roller with
cleaner
Tape is not
inserted into
the slot.
Some program
is played back
repeatedly
Yes
No
Yes
Tape was inserted
right side left.
Tape is ejected
after being
inserted.
Insert recording
part to right side.
Ref.
Tape Deck Macha
TN-715, TN-301
Ref.
Tape is cut or
extended
Ref.
Check on L.C.D
and press RPT
button.
Yes
Yes
Selected repeat
(RPT) function.
Release RPT
function
Yes

4. ADJUSTMENTS
7
4-1. EQUIPMENTS CONNECTIONS

ADJUSTMENTS
4-2. TUNER MODULE ADJUSTMENT LOCATIONS
8

ADJUSTMENTS
4-3. AM (MW/LW) ADJUSTMENT METHOD
9
STEP
1 Band Covering
RF-Tracking
Figure 1
Figure 2
Figure 2
522KHz 30dBu
Mod 1000Hz 30%
603KHz 30dBu
Mod 1000Hz 30%
1404KHz 30dBu
Mod 1000Hz 30%
522KHz
603KHz
1404KHz
Adjust AM OSC coil
to reach VT1.2V
Fig.7
Adjust AM RF1 and
AM RF2
for maximum output
Fig.7
Adjust AM RF1 and
AM RF2
for maximum output
Fig.7
RF-Tracking
2
3
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
4-4. FM ADJUSTMENT METHOD
10
STEP
1 IF (Zero Volt)
RDS AF level
Figure 3
Figure 2
Figure 5
98.1MHz 60dBuV
No Modulation
98.1MHz 30dBuV Mod.
1kHz 45KHz DEV.
Mono
98.1MHz 40dBuV
Mod.
1kHz 45KHz DEV.
Stereo Left at Right ch.
98.1MHz
98.1MHz
98.1MHz
Adjust FM DET
for 0V + 0.03V
Fig.3 (CW03)
Adjust RV 101 on main
PC Board
for2.5V+20mV at
TP101(IC401 pin 66)
Adjust Stereo Blend
RV01 on Tuner PCB
Fig.7 10+3dB
separation between Left
and Right ch.
SNC
2
3
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
Note : dBu uV dBu 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”

ADJUSTMENTS
4-5. TAPE ADJUSTMENT METHOD
11
NOTE : 1. Clean the playback head before adjustment
2. Prepare the test tape MTT-114 or equivalent
3. Balance, Fader, Bass & Treble ....Center position. Volume adjusted to 2Volts.
STEP
1Head azimuth
adjustment
Tape Speed
Figure 6
Figure 6
MTT-114N
or equivalent
MTT-114N
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

12
5. SCHEMATIC DIAGRAMS
5-1. BASIC Series AKF-3825
Size:A3

13
5-2. BASIC Series AKF-8825
SCHEMATIC DIAGRAM
Size:A3

14
5-3. RDS Series AKF-8825R
SCHEMATIC DIAGRAM
Size:A3

PART SIDE
6-1. PCB MAIN
15
6. PARTS LOCATION ON P.C. BOARD
AKF-3825 / AKF-8825 Basic & RDS

PARTS LOCATION ON P.C. BOARD
16
BOTTOM SIDE

6-2. PCB FRONT
17
PARTS LOCATION ON P.C. BOARD
PART SIDE
BOTTOM SIDE

18
PARTS LOCATION ON P.C. BOARD
6-3. ISO PCB