SAMSUNG ST48 Alignment and Adjustments

1. Alignment and Adjustments
1-1 Tuner
Samsung Electronics 1-1
FM Stereo Adjustment
L-CH/R-CH : Maximum(Figure 1-3)
SSG FREQ.
Frequency
Adjustment point
98MHz
98MHz
SVR100
Figure1-3 FM Stereo Separation Adjustment
Figure1-1 IF CENTER and THD Adjustment
FM SSG
75 Dummy
5K
Stereo Modulator (Pilot 10%)
OUT
Oscilloscope
FM antenna
SET
Speaker Terminal
EXT
GND
VTVM
FM SSG
Output GND
Speaker Terminal
FM Antenna Terminal
Distortion Meter
Input
SET
Input
output
Oscilloscope
FREQ:1KHz MOD : 40KHz DEV
FM IF Adjustment
L-CH/R-CH : Maximum(Figure 1-1)
SSG FREQ.
Frequency
Adjustment point
10.7MHz
87.5MHz
T101
T103(Green)
FM TRACKING Adjustment
L-CH/R-CH : Maximum(Figure 1-3)
SSG FREQ.
Frequency
Adjustment point
90MHz,106MHz
90MHz,106MHz
L101,TC100
FM Coverage Adjustment
L-CH/R-CH : Maximum(Figure 1-3)
SSG FREQ.
Frequency
Adjustment point
87.5MHz,108.5MHz
87.5MHz,108.5MHz
L102,TC101
1-2 Samsung Electronics
1-1-1 Test Equipment
1-1-2 Pre-Adjustment
1-1-3 AM(MW) Adjustment
1. AM Standard Signal Generator (S.S.G) : 400Hz, 30% MOD
2. Oscilloscope
3. VTVM
4. Frequency counter
5. Loop antenna
6. Dummy load (3Ω)
7. DC voltmeter
1. Check the source voltage
2. Press TUNER/BAND to select the AM(MW) function.
3. Set the EQ/S.BASS control to OFF position.
4. Set the volume control to approximaterly 50mw
Intermediate frequency (IF) adjustment
AM frequency coverage adjustment
AM tracking adjustment
Figure 1-4
Connect DC voltmeter to AM VT(OR10) and GND
1
2
4
5
3
Figure 1-5
Figure 1-5
455 KHz
600 KHz
Figure 1-4
SET
60 cm
AM Signal Generator
Test Loop Antenna
Speaker Terminal
VTVM
IN
OUT
GND
Oscilloscope
AM-ANT
Figure 1-5
SET
AM VT(OR10)
GND
DC Voltmeter
600 KHz
L105(BAR ANT)
515 KHz
1400 KHz 1400 KHz TC102
TC103
1650KHz
1650KHz
-
515 KHz
515 KHz
T102(White)
T100(Red)
1.0V
Maximum output
Maximum output
4.6V
Remark
FREQ. Setting
Adjust. PointSSG.FREQ.Item
Step
Connection
Alignment and Adjustments
1-2 Cassette Deck
Dummy Load(3Ω)
1-2-1. Recording BIAS adjustment
1) Connect frequency counter to C402 (See Fig.1-6)and press the Record button.
2) Adjust T400 (BIAS OSC COIL) until frequency counter reads 39.5~40.5KHz.
1-2-2. Tape AZIMUTH adjustment
1) Connect the equipments as per Fig.1-8 to adjust the tape azimuth with test tape (recorded at 6.3KHz : MTT-113N)
2) Play the test tape after inserting in DECK.
3) Adjust the azimuth ajustment screw of left side of record/play head for maximum output and for the same channel phase. (see Fig.1-7)
1-2-3. Tape speed adjustment
1) Connect the equipments as shown in Fig.1-8 adjust the tape speed with test tape (recorded at 3KHz : MTT-111N)
2) Adjust SVR OF MOTOR until frequency counter reads 3KHz±1%.
Fig.1-6 Recording bias adjustment
Fig.1-8
Fig.1-7 Azimuth speed adjustment
80KHz
FREQUENCY COUNTER
PRE/REC PART
C402
Adjustment
Adjustment screw
R/P head
UNIT UNDER TEST
VTVM
OSCILLOSCOPE
FREQUENCY COUNTER
3000Hz
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