Adjustments - Daewoo AMI-910L 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 scr ewdr i ver wi t h pl ast i c or cer am i c gr i p f or al l adj ust m ent s.
2. St andar d t est f r equency 1 KH z and devi at i on 75 KHz f or 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)
Unl ess ot her speci f i ed set bei ng swi t ched FM m ode, adj ust gener at or ' s f r equency t o cent er of t he FM band wher e no FM br oadcast exi st s.
O t her wi se adj ust m ent of FM usabl e sensi t i vi t y , f r equency r ange f or FM band ar e not needed, but conf i r m t hese dat a ar e sat i sf i ed wi t h speci f i -
cat i on.
CAUTI O N : W hen r eal i gni ng t he FM r ecei vi ng f r equency t he hi ghest end of t he f r equency r ange shoul d not be m or e t han 108 M H z and t he
l owest end of t he f r equency r ange shoul d not be l ess t han 87. 5 M H z, i n or der t o com pl y wi t h FTZ r egul at i on i n W est G er m any.
2. CD SECTION
Note: 1. Use t he osci l l oscope wi t h m or e t han 10M Ωi m pedance.
2. Cl ean t he l aser obj ect l ens usi ng nat ur al det er gent and a sof t appl i cat or when t he si gnal l evel i s l ow er t han t he val ue as i ndi cat ed i n
t he f ol l ow i ng 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 across R201
Connect DC voltme-
ter across 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
Dev. 26dB
FM 98MHz
75KHz Dev.
RV201
µ
26dB
FM Antenna
Terminal(75 ohm)
SET
Ω
FM 75/ 50
Dum m y
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