Daewoo AMI-921DP User manual

Service Manual
MINI COMPONENT SYSTEM
Model :
DAEWOO ELECTRONICS CO., LTD.
AMI-921DP / 921DPR

1
TABLE OF CONTENTS
SAFETY PRECAUTIONS ................................................................................................. 2
ADJUSTMENTS............................................................................................................. 4
EXPLODED VIEW AND PARTS LIST ................................................................................ 7
WIRING DIAGRAM ..................................................................................................... 9
BLOCK DIAGRAM ...................................................................................................... 10
SCHEMATIC DIAGRAM ............................................................................................... 11
POWER / AMP ...................................................................................................................................11
CD ...................................................................................................................................................12
TUNER ...............................................................................................................................................13
TAPE .................................................................................................................................................16
CONTROL .........................................................................................................................................17
PCB PATTERN LAYOUT ................................................................................................. 18

2
WARNING : TO PREVENT FIRE OR ELECTRIC SHOCK, DO NOT EXPOSE
THIS APPLIANCE TO RAIN OR MOISTURE.
CAUTION : TO REDUCE THE RISK IF ELECTRIC SHOCK, DO NOT
REMOVE COVER (OR BACK). NO USER SERVICEABLE PARTS
INSIDE.
REFER SERVICING TO QUALIFIED SERVICE PERSONNEL.
THIS SYMBOL IS INTENDED TO ALERT THE USER TO THE
PRESENCE OF UNINSULTED "DANGEROUS VOLTAGE"
WITHIN THE PRODUCT'S ENCLOSURE THAT MAY BE
SUFFICIENT MAGNITUDE TO CONSTITUTE A RISK OF
ELECTRIC SHOCK TO PERSONS.
THIS SYMBOL IS INTENDED TO ALERT THE USER TO THE
PRESENCE OF IMPORTANT OPERATING AND MAINTENANCE
(SERVICING) INSTRUCTIONS IN THE LITERATURE
ACCOMPANYINGTHEAPPLIANCE.
CAUTION
TO PREVENT ELECTRIC SHOCK, DO NOT USE THIS POLARIZED AC
PLUG WITH AN EXTENSION CORD, RECEPTACLE OR OTHER OUTLET
UNLESS THE BLADES CAN BE FULLY INSERTED TO PREVENT BLADE
EXPOSURE.
LASER SAFETY
THISUNITEMPLOYSA LASER. ONLYQUALIFIEDSERVICE PERSONNEL
SHOULD REMOVE THE COVER OR ATTEMPT TO SERVICE THIS DEVICE
DUE TO POSSIBLE EYE INJURY.
CAUTION: USEOFANYCONTROLS,ADJUSTMENTS, ORPROCEDURES
OTHER THAN THOSE SPECIFIED HEREIN MAY RESULT IN HAZARDOUS
RADIATION EXPOSURE.
CAUTION : TO PREVENT ELECTRIC SHOCK, MATCH WIDE BLADE OF
PLUG TO WIDE SLOT, FULLY INSERT.
ATTENTION : POUR EVITER LES CHOCS ELECTRIQUES, INTRODUIRE
LA LAME LA PLUS LARGE DE LA FICHE DANS LA BORNE CORRESPON-
DANTE DE LA PRISE ET POUSSER JUSQU'AU FOND.
Important Safety Instructions
- All the safety and operating instructions should be read before
the appliance is operated.
- The safety and operating instructions should be retained for
futurereference.
- All warnings on the appliance and in the operating instructions
shouldbe adhered to.
- All operating and use instructions should be followed.
1. Water and Moisture - The appliance should not be usednear
water - for example, near a bathtub, washbowl, kitchen sink,
laundry tub, in a wet basement, or near a swimming pool,
and the like. 2. Carts and Stands - The appliance
should be used only with a cart or
stand that is recommended by th
manufacturer.
3. An appliance and cart combination
should bemoved with care. Quick
stops, excessive force, and uneven
surfaces may cause the appliance
and cart combination to overturn.
4. Wall or Ceiling Mounting - The appli-
ance should be mounted to a wall or
ceiling only as recommended by the manufacturer.
5. Ventilation - The appliance should be situated so that its
location or position does not interfere with itsproper
ventilation. Forexample,theappliance shouldnotbesituated
on a bed, sofa, rug, or similarsurface that may block the
ventilation openings; or, placed in a built-in installation, such
as a bookcase or cabinet that may impede the flow ofair
through the ventilation openings.
6. Heat- The appliance should besituated away from heat
sources such as radiators, heat registers, stoves, or other
appliances(including amplifiers) that produceheat.
7. Power Sources - The appliance should be connected to a
power supply only of the type described in the operating
instructions or as marked onthe appliance.
8. Grounding or Polarization - The precautions that shouldbe
taken so that the grounding or polarization means of an
appliance is not defeated.
9. Power - Cord Protection - Power-supply cords shouldbe
routed so that they are not likely to be walked on or pinched
by items placed upon or against them, paying particular
attention to cords at plugs, convenience receptacles, and the
pointwhere they exit from the appliance.
10.Protective Attachment Plug - The appliance is equipped with
an attachment plug having overload protection. This is a
safetyfeature. See Instruction Manual for replacement or
resettingof protective device. If replacement of the plug is
required,be sure the service technician has used a
replacement plug specified by the manufacturer that has the
same overload protection as the original plug.
11.Cleaning - The appliance should be cleaned only as
recommended by the manufacturer.
12.Power Lines - An outdoor antenna should be located away
from power lines.
SAFETY PRECAUTIONS
CAUTION
RISK OF ELECTRIC SHOCKS
DO NOT OPEN
PORTABLE CART
Figure2

3
SAFETY PRECAUTIONS
13.Outdoor Antenna Grounding - If an outside antenna is
connected to the receiver be sure the antenna systemis
grounded so as to provide some protection against voltage
surges and built-up static charges. Article 810 of the National
ElectricalCode, ANSI/NFPA 70, provides information with
regardto proper grounding of the mast and supporting
structure, grounding of the lead-in wire to an antenna-dis
charge unit, size of grounding conductors,location of antenna-
discharge unit, connection to grounding electrodes and
requirements for the grounding electrode. See Figure 1.
14.Non-use Periods - The power cord of the appliance should be
unpluggedfrom the outlet when left unused for a long period
of time.
15.ObjectandLiquidEntry- Care shouldbetakenso thatobjects
donotfallandliquidsarenotspilledintotheenclosurethrough
openings.
16.Damage Requiring Service - The appliance should be
serviced by qualified service personnel when:
a) The power-supply cord or the plug has been damaged;or
b) Objects have fallen, or liquid has been spilled intothe
appliance; or
c) The appliance has been exposed to rain; or
d) The appliance does not appear to operate normally or
exhibits a marked change in performance; or
e) The appliance has been dropped, or the enclosure
damaged.
17.Servicing - The user should not attempt to service the
appliance beyond that described in the operating instructions.
All other servicing should be referred to qualified service
personnel.
ANTENNADISCHARGEUNIT
(NECSECTION 810-20)
ANTENNALEAD
INWIRE
POWERSERVICE GROUNDING
ELECTRODESYSTEM
(NECART 250PARTH)
GROUNDCLAMP
ELECTRIC
SERVICE
EQUIPMENT
GROUNDINGCONDUCTORS
(NECSECTION 810-21)
GROUNDCLAMPS
EXAMPLEOFANTENNA
GROUNDING
NEC- NATIONALELECTRICAL CODE

4
ADJUSTMENTS
1. TUNER SECTION
TEST EQUIPMENT
1. Signal Generator with a frequency range of FM broadcast.
2. Oscilloscope with a side amplifier of approximately 100 KHz.
3. FM 75/50 Ω dummy antenna.
4. VTVM
FM ALIGNMENT
1. Turn on the FM signal generator and the VTVM allowing 15 minutes warming-up period.
2. Connect the VTVM across the headphone jack or speaker terminal.
3. Set signal generator frequency as listed in ALIGNMENT CHART and maintain a sufficient output level to provide an
indication on VTVM.
NOTE
1. Use a screwdriver with plastic or ceramic grip for all adjustments.
2. Standard test frequency 1 KHz and deviation 75 KHz for FM.
- FM RF, IF ALIGNMENT CHART -
Unless other specified set being switched FM mode, adjust generator's frequency to center of the FM band where no FM broadcast exists
Otherwise adjustment of FM usable sensitivity, frequency range for FM band are not needed, but confirm these data are satisfied with specifi-
cation.
CAUTION : When realigning the FM receiving frequency the highest end of the frequency range should not be more than 108 MHz and the
lowest end of the frequency range should not be less than 87.5 MHz, in order to comply with FTZ regulation in West Germany.
2. CD SECTION
Note: 1. Use the oscilloscope with more than 10M Ω impedance.
2. Clean an object lens by an applicator with natural detergent when the signal level is lower than specified value
with the following checks.
RF LEVEL CHECK
1. Connect oscilloscope to test point TP502 and IC502
Pin66 on CD PCB.
2. Press power switch on.
3. Put test disc(TCD-781) in and press play button then
pause button.
4. Confirm that oscilloscope waveform is clear. Clear
RF signal waveform means that the shape"#"can be
clearly distinguished at the center of waveform.
5. Adjust RV501 to geta clear waveform and maximum
amplitude.
Step Item Input Circuit Setup Output Circuit Setup Tuner Setting Adjust Point Adjustment
1FM IF
Adjustment
Connectstereosignal
generator to FM ANT
terminal (J001)
Connect DC voltme-
ter to edge R201 FM98MHz75KHz
Dev. 26dB µ
L203 Adjust forDC 0V
± 0.1V
2Auto Stop
Sensitivity
Connectstereosignal
generator to FM ANT
terminal (J001)
Connect DC voltme-
ter to edge of RV201
FM 98MHz
75KHzDev.
26dB µ
RV201
Adjust for DC
1.17V ± 0.02V
Confirm stereo indica-
tor is lighted and L/R
channel is separated.
SET
FM Antenna
Terminal(75 ohm)
Carrier Frequency : 98MHz
Output Level : 26dBuV
Modulation:Audio 1kHZ, 75kHz Deviation
FM RF SSG
75 ohm Coaxal
Level : 1.2+0.3Vp-p
RF Signal Waveform VOLT/DIV : 200mV
TIME/DIV : 50ns

5
ADJUSTMENTS
E-F BALANCE ADJUSTMENT
1. Connect oscilloscope to test point TP502 and TP503
on CD PCB.
2. Press power switch on.
3. Put test disc(TCD-781) in and press play button then
pause button.
4. Pressing Fast Forward button, adjust RV502 to get
thattheoscilloscopewaveformissymmetricalon the
bottom in relation to 0V, and check this level.
* Design and specifications may be subject to change without notice.
3. TAPE SECTION
Test Tape be used
HEAD ADJUSTMENT (AZIMUTH)
1. 10KHz test tape(example: MTT-114N) must be used for this adjustment.
2. Connect to VTVM or oscilloscope to the headphone jack or speaker terminal.
3. Press the play button.
4. Adjust the azimuth by using a screw driver to maintain the max. L&R output voltage.
5. Adjust tape A(1), tape B(2) respectively, Please secure the azimuth position by using locking paint.
RECORDING BIAS OSCILLATOR FREQUENCY ADJUSTMENT
1. Connect the frequency counter to TP603, GND.
2. Press the REC button.
3. Adjust L603 to obtain 80 KHz ± 100Hz
Tape Contents Use
MTT-111N 3 KHz Tape Speed Adjustment
MTT-114N 10 KHz Head Azimuth Adjustment
MTT-5511 Blank Record Frequency Property
Traverse Waveform
A
B
0V
VTVM
Scope
R-CH
L-CH
47 kohm
47 kohm
Input Level
Measurement
Point
Input Point
Output Level
Measurement
Point

6
ADJUSTMENTS
TAPE ALIGNMENT CHART
Step Item Reference Value Test Tape Adjust Point Test Point Note FIG.
1Tape Speed
Adjustment
Normal
3,015~3,025Hz MTT-111N RV601 Line Out L/R
Channel Confirm Wow & Flut- ter is within 0.35% FIG.1
3,000~3,010Hz MTT-111N RV601 Line Out L/R
Channel
Confirm Tape Speed
of end position after
adjustment at tape
start position
FIG.1
High 5,820~6,180Hz MTT-111N - - - - - - Shorted TP601,
TP602
Confirm High speed
after normal speed
adjustment FIG.1
2Azimuth Adjustment Maximum Level
Phase:Within90° MTT-114N Head Screw Line Out L/R Channel FIG.2,3,4
3Recording Bias Oscilla- tor Frequency Adjust-
ment 80 KHz±0.5 MTT-5511 L603 TP603,GND Adjustwith frequency
counter connected. FIG.1
FIG. 1 : Tape Speed & Record Bias Oscillator
Frequency Adjust Circuit
Test Tape : MTT-111N(3kHz)
MTT-5511(Blank)
Frequency Counter
Output Level
Measurement Point
Set
FIG. 2 : Tape Azimuth Adjust Location
(Record/Playback Head)
FIG. 3 : Tape Azimuth Adjust Head Screw & Waveform FIG. 4 : Tape Azimuth Adjust Circuit & Waveform
Forward
Side Reverse
Side
Adjust with Frequency
Counter Connected
L-CH
Peak
R-CH
Peak
Screw
Angle
Output Level
within
1 dB within
1 dB
L-CH
Peak R-CH Peak Screw Angle
VH
Oscilloscope
L-CH
Output Level
Measurement Point
Set
Test Tape
MTT-114N
(10kHz)
Screen Pattern
In Phase 45 90 135 180
Good Wrong

7
EXPLODED VIEW AND PARTS LIST
AMI- 921DP / 921DPR

8
EXPLODED VIEW AND PARTS LIST
No. Parts Name PARTS Code Description Q'ty
1WINDOW DOOR A/B 9CD16148A0 ACRYL 1
9CD16148B0 ACRYL 1
2DOOR COVER A/B 9CD18100A0 MIPS 1
9CD18100B0 MIPS 1
3DOOR FRAME A/B 9CD1809400 ABS 1
9CD1809500 ABS 1
4SPRING DOOR EJECT L 9CD30080L0 STS 1
5SPRING DOOR EJECT R 9CD30080R0 STS 1
6CUSHION FOOT 9CD4207700 URETHAN FOAM RUBBER 2
7KNOB VOLUME 9CD1337000 ABS 1
8DAMPER ASSY 9CDM029800 2
9LOCKER ASSY 9CDM029900 2
10 PLATE DECO 9CD0910200 PVC SHEET (T=1.0) 1
11 KNOB JOG DIAL 9CD1336800 ABS 1
12 BRKT SIDE 9CD2412900 ABS 2
13 PANEL FRONT 9CD0306700 MIPS 1
14 WINDOW FLT 9CD1614700 ACRYL 1
15 KNOB EQ 9CD1336600 ABS 1
16 KNOB POWER 9CD1336900 ABS 1
17 KNOB FUNCTION 9CD1336700 ACRYL 1
18 PLATE FILTER 9CD0910300 LEXAN (T=0.125) 1
19 KNOB CONTROL 9CD1336500 ABS 1
20 KNOB DISC 9CD1337500 ABS 1
21 KNOB CD 9CD1336400 ABS 1
22 GUIDE FLT 9CD2506300 ABS 1
23 CASS DECK 9CD6007000 S/S ADR 2138MW 1
24 HOLDER PCB DECK 9CD2303600 MIPS 2
25 DOOR CD 9CD1810100 MIPS 1
26 HEAT SINK 9CD4402800 BSP T=0.5 1
27 CD MECHANISM 9CD6007100 CMS FR3 B TYPE 1
28 COVER TOP 9CD0409600 MIPS 1
29 COVER SIDE L 9CD0409900 MIPS 1
30 CHASSIS BOTTOM 9CD0607100 SECC 1
31 HEAT SINK DP2 9CD4405600 AL 4.0T 1
32 BRACKET HEAT SINK 9CD2414400 SUS T=0.3 1
33 HOLDER AC CODE 9CD2303300 ABS 1
34 BRACKET PCB A 9CD2413100 SECC T=1.0 1
35 HEAT SINK P 9CD4404200 AL T=2.0 1
36 COVER SIDE R 9CD0410000 MIPS 1
37 COVER BACK 9CD0409807 MIPS 1
S1 SCREW TAPTITE 7173261011 TT2 BIN 2.6X10 MFZN 19
S2 SCREW TAPTITE 7173300611 TT2 BIN 3X6 2
S3 SCREW TAPTITE 7173301011 TT2 BIN 3X10 MFZN 18
S4 SCREW TAPTITE 7173301012 TT2 BIN 3X10 BK 18
S5 SCREW TAPTITE 7173301212 TT2 BIN 3X12 BK 5
S6 SCREW TAPTITE 7173400611 TT2 BIN 4X6 6
S7 WASHER SCREW 9CD3102400 TT2 BIN 3X10+D14 5
P1 PCB CD 9CD6574800 197 X 123.5 X 1.6T 1
P2 PCB FRONT 9CD6577400 247 X 139 X 1.6T 1
P3 PCB MAIN 9CD6577600 319 X 197 X 1.6T 1
P4 PCB POWER 9CD6577900 197 X 115 X 1.6T 1
P5 PCB TAPE 9CD6577200 107 X 163 X 1.6T 1
P6 PCB OPTICAL JACK 9CD6577800 29 X 21.5 X 1.6T 1
No. Parts Name PARTS Code Description Q'ty

9
WIRING DIAGRAM
AMI- 921DP / 921DPR

10
BLOCK DIAGRAM
AMI-921DP / 921DPR

11
SCHEMATIC DIAGRAM
1. POWER / AMP
AMI-921DP / 921DPR

12
SCHEMATIC DIAGRAM
2. CD
AMI-921DP / 921DPR

13
SCHEMATIC DIAGRAM
3. TUNER
AMI-921DP / 921DPR 2-Band

14
SCHEMATIC DIAGRAM
AMI-921DP / 921DPR FTZ 2-Band

15
SCHEMATIC DIAGRAM
AMI-921DP / 921DPR FTZ 3-Band

16
SCHEMATIC DIAGRAM
4. TAPE
AMI-921DP / 921DPR

17
SCHEMATIC DIAGRAM
5. CONTROL
AMI-921DP / 921DPR

18
PCB PATTERN LAYOUT
AMP / TUNER
* AMI-921DP

19
PCB PATTERN LAYOUT
CD TAPE
* AMI-921DP / 921DPR * AMI-921DP / 921DPR
POWER
* AMI-921DP / 921DPR