Adjustments - Daewoo AMI-921DP Service Manual

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 75/50Ω 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.
Step Item Input Circuit Setup
Connect stereo signal
FM IF
1 generator to FM ANT
Adjustment
terminal (J001)
Connect stereo signal
Auto Stop
2 generator to FM ANT
Sensitivity
terminal (J001)
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 10MΩ 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 get a clear waveform and maximum
amplitude.
- FM RF, IF ALIGNMENT CHART -
Output Circuit Setup Tuner Setting
FM98MHz75KHz
Connect DC voltme-
ter to edge R201
Dev. 26dB
Connect DC voltme-
ter to edge of RV201
RF Signal Waveform
4
FM RF SSG
75 ohm Coaxal
Carrier Frequency : 98MHz
Output Level : 26dBuV
Modulation:Audio 1kHZ, 75kHz Deviation
Adjust Point
L203
µ
FM 98MHz
75KHz Dev.
RV201
µ
26dB
FM Antenna
Terminal(75 ohm)
SET
Adjustment
±
Adjust forDC 0V 0.1V
Adjust for DC
±
1.17V 0.02V
Confirm stereo indica-
tor is lighted and L/R
channel is separated.
VOLT/DIV : 200mV
TIME/DIV : 50ns
Level : 1.2+0.3Vp-p