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ADJUSTMENTS
TEST EQUIPMENTS
1. AM Signal Generator with frequency range of at least from 450 kHz to 13 MHz.
2. FM Signal Generator with 10.7 MHz marker signal.
3. AM Sweep Generator of 455 kHz center frequency.
4. FM Sweep Generator with a wide band amplifier of approximate 500 kHz, with 10.7 MHz marker signal.
5, Oscilloscope with a wide band amplifier of approximate 100 kHz.
6. Loop Antenna. (AM)
7. Test loop — a three turn loop antenna of 1 cm diameter. (FM-IF)
8. Test loop — a coil of any size wire with one turn or more. (AM-IF)
9. VTVM
10. Dummy antenna. (FM)
11. Adjustment Screwdriver.
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T102
103 TIO4 ..
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Figure 7
AM ALIGNMENT
1. Turn onthe AM signal generator, sweep generator and the VTVM allowing a fifteen-minute warm-up period.
2. First, do the AM-IF Alignment (AM ALIGNMENT CHART-Step 1), refering to Figure 8 .
3. Using the test loop across the output of the signal generator, inductively connect the signal generator to the radio.
(Figure 9)
Connect the VTVM across the Headphone jack.
5. Set signal generator frequency
as listed in ALIGNMENT
CHART and maintain a sufficient output level to provide an
indication on VTVM.
6. Set volume control at mid-position,
AM 455 kHz
a
SCOPE
KT-4087/V780
AM SWEEP
GENERATOR
ONE-TURN COIL
SCOPE
ANTENNA COIL
Figure 8
AM SIGNAL
GENERATOR
UNIT UNDER TEST
HEADPHONE
Figure 9
ck
AM ALIGNMENT CHART
Generator
:
.
:
:
Band
Step
Frequency.
Radio Dial Setting
Adjustment
Remarks
Tuning Gang Fully Counter-
T102 (GR)
Adjust coil T102 and
AM-IF
455 kHz
clockwise
T104 until best signal
T104 (N)
:
:
(Lowest Frequency)
peak is obtained.
Adjust R194 so that 1.0 +0.05V is obtained at TP2, using a VTVM with high input impedance.
i
Full
-
TERING ISNRP
WINECOHIES!
Osc. Coil
Adjust for maximum
515 kHz
clockwise
LL
'adication
(Lowest Frequency)
003
Pees
1650 kHz
Tuning Knob Fully Clockwise
Osc. Trim.
Adjust for maximum
(Highest Frequency)
C191
indication,
2
3
Repeat steps 2 and 3 as required.
AM
;
Ant. Trim.
Adjust for maximum
a
1400 kHz
Tune to Signal.
C192
'cications
Repeat steps 5 and 6 as required.
FM ALIGNMENT
. Set the select switch to FM position,
Turn on both sweep generator and oscilloscope, and allow a fifteen-minute warm-up period.
. Connect the RF SWEEP SIGNAL OUTPUT of the sweep generator through the loop antenna to the receiver. (Figure 10)
Connect the oscilloscope Vertical input directly to the test point TP1 and connect the shielded lead to the ground.
Connect the SWEEP VOLTAGE OUTPUT of the sweep generator to the oscilloscope Horizontal input.
Proceed as outlined in the FM-IF ALIGNMENT
CHART.
DAWN
>
FM-IF ALIGNMENT CHART
Sen [eo | ow | comm [Sm]
hm
Set scope for con-
necting output
ee
Connect Sweep
generator of
Adjust coil T103 in order
until the best S curve is
obtained. (Figure 11)
fe)
f
-
i
i
generator output t
10.7 MHz
ully counter-|
to vertical axis
a three-turn loop
center freq,
clockwise
of scope
''V
antenna of 1 cm
with 10.7
(Lowest
and sweep gener-
diameter.
Waits career.
Frequency.)
ator output to
horizontal axis
"HT
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