Lafayette LR 9090 Service Manual

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QIOmI _modulor II i componenU- lafayette [#9090
Pages 33-42 Courtesy of LAFAYETTE RADIO ELECTRONICS

AM ALIGNMENT-SELECTOR IN AM POSITION

Connect generator across loop fashioned of several turns of wire. Set volume at maximum.

GENERATOR RADIO DIAL

FREQUENCY SETTING INDICATOR ADJUST REMARKS

4SSkHz Tuning gang Output meter Adjust for maximum. Repeat until
400~hertz fully open across voice coil CFA no further improvement is noted.
Modulation

600kHz 600kIlz T4 Adjust for maximum.

1640kHz 1640k11'z " CT7,CT6,T3 Adjust for maximum.

l400kHz l400kIIz " CTS Adjust for maximum. Repeat AM alignment

until no further improvement is noted.

FM IF ALIGNMENT USING FM SIGNAL GENERATOR-SELECTOR IN FM POSITION
High side of generator thru .OOluF to Base FTR}.

Use 60-hertz, frequency-modulated signal, 450kHz sweep.

Use 60-hertz sawtooth voltage in scope for horizontal deflection.

GENERATOR RADIO DIAL

FREQUENCY SETTING INDICATOR ADJUST REMARKS

10.7MH2 Point of non~ Vert input of T2,FTS(l) Disconnect stabilizing capacitor

450kHz Sweep interference scope to T1, L3 Adjust for maximum gain and symmetry
Junction of response similar to Fig. l.

Reconnect
" " Vert input of Tl (1) Adjust T1 for maximum amplitude

scope to posi- and straightness of line, similar to
tive end C25 Fig. 2.

FM RF ALIGNMENT-SELECTOR IN FM POSITION

Connect generator across antenna terminals with 120~ohm carbon resistor in series with each lead.
Adjustment of coils by bending should not be attempted unless the coil is deformed or replaced.

GENERATOR RADIO DIAL
FREQUENCY SETTING INDICATOR ADJUST REMARKS
108MHz 108MHz DC probe of VTVM FT4,FT3, Adjust for maximum.
Modulated to positive end FT2,FT1
C25
SSWZ SSMHZ CT4,CT3 Adjust for maximum. Repeat FM RF steps
Modulated CT2,CT1 until no further improvement is noted.
lngZ

Disconnect coupling Lytic C25. Adjust RV4 for 19kHz +20Hz at TP4.

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FM SYEREO ADJUSTMENT

control {W}. for best separation.

Tune receiver for a stereo signal. Adjust balance control for equal channel output. Adjust Separation

Signal Strength

For AM Tune strong AM station, adjust RV 2 for Maximum deflection
on Signal Meter Ml.

For FM Tune strong signal, adjust tuning for 0 on Tuning Meter M2
and adjust RVl for Maximum deflection on Meter M1.

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Lafayette [3-30.90

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