Rotel RX-403 Techische Beschreibung Seite 10

FM SIGNAL
GENERATOR
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FM IF and RFAlignment Procedure
Instruments : FMSignal G enerator andH.D.Analyzer.
Set Function Selectorto "FM" position.
. Push MODE Switch set FM MUTING out.
• Set VR301 to mid-position.
• Connect FM Signal Generator to FM antenna ter-
minal.
• Connec t e Oscilloscop
Jack.
A. FM IF ALIGNMENT
l. SetSignal Generator Frequency at98MHz(400Hz,
100%Mod.) and adjustthe tuning to maximum
output. (The antennaterminal voltageshouldbe
1m V.)
2. Adjust the meterbalance by adjusting the lower
core Of L 109.
3. Adjust IF Coil L107 in front end to obtain maxi-
mum deflection on scope.
4. Setdistortionto minimumby adjusting t heupper
core of 1.109.
B. FM RF ALIGNMENT
I. Set Signal Generator Frequency at 106M Hz
(400Hz, 100%Modulation) and alsotune receiver
at 106MHzon the dial scale. T henadjustFM OSC
trimmer CT3 (on VC) to obtain maximumdeflec-
tion on scope.
H.D. ANALYZER
OSCILLOSCOPE
REAR PANEL
o
andH.D.Analyzer t o Tape Out
IC 101
L103
L109
L104
FM IF L107
ICJOI
VR 301
CT3
FM
CHASSIS TOP VIEW(FM PORTION)
Fig.5. FM IF and RFAlignmentHook-Up
Fig. 5. UKW-ZF.und HF-Einstellung
Fig. 5. Alignement
Setthe receiver a t 90MHzon the dial scale, and
2.
changethe frequency Of SignalGenerator so that
the output of the TAPE OUT becomesmaximum.
Thenmake sureSignal G enerator frequency stays
within 90MHz± 150KHz.
3. Sensitivityon this alignment m ustbe attempted
at 106MHz by adjusting CTI and CT2 to obtain
maximum deflection on scope, and fine tune to
balance sensitivity at 90 and 106MHz
4. AdjustFMOSCcoil L105andFMRFcoil L101,
102, 103 and 104 asdescribed belowonly when
tracking and sensitivity adjustments are not
attained by adjusting CT 1, CT2, and CT3.
Fine tune Signal Generator and receiver to
a.
90MHz, and adjust L107, L101, L102, L103
and L 104,
b. Fine tune Signal Generator and receiver to
106MHz and adjust CTI, CT2 and CT3 so that
maximum output is obtained.
Repeat s tepa andb to obtain enough effect.
c.
LIOI FM ANT
1.102 FM
L105
FM OSC
CT2 CTI
FM RF FM ANT
FM IF et HF
RF