Realistic PRO-2021 - IF Section Alignment; VCO Alignment; Reference Frequency OSC Alignment

IF SECTION ALIGNMENT
Step 1: Connect instruments as shown below.
*15kHz
TP1 UNIT 4
о UNDER TEST
455kHz
3.8—42VP.P
10.7 MHz |
o
OIF
|SWEEP
GENERATOR
|
¥
—15kHz
INPUT : 100uV
Step 2: Adjust T10 for maximum output so that the 455 kHz marker is in the center of the discrimi-
nator curve and for best linearity, as shown above.
During alignment, maintain Sweep Generator output at the lowest level possible to prevent
overloading.
VCO ALIGNMENT
VHF LO BAND
Step 1: Connect a DC SSVM to ТРЭ and ground.
Step 2: Program CH1, 2 and 3 as follows:
CH1 (30 MHz), CH2 (40 MHz), CH3 (54 MHz).
Step 3: Select Channel 3 (54 MHz) and adjust ТСЗ for 13V on the DC SSVM.
Step 4: Select Channel 1 (30 MHz) and adjust T7 for 1.0V on the DC SSVM.
Step
5:
Repeat
steps
3
and
4
until
no
improvement
is
observed.
The
DC
SSVM
should
read
as
below.
30 MHz Voltage at TP5 0.9 — 1.0V
40 MHz Voltage at TPB 4.1 — 4.5V
54 MHz Voltage at ТРБ 12.5 — 13.1V
REFERENCE FREQUENCY OSC ALIGNMENT
Step
1:
Connect
Frequency
Counter
to
Q7
Collector
through
a
ceramic
capacity
(47
~
100
pF)
and
ground.
Step 2: Select Channel 2 (40 MHz) and observe VCO Frequency.
Step 3: Adjust TC6 so that the frequency is 50.700 MHz +20 Hz.
Step 4: Repeat VHF LO BAND VCO ALIGNMENT.
AIRCRAFT HI BAND AND UHF BAND
Step 1: Connect a DC SSVM to TP-5 and ground.
Step 2: Program CH1, 2, and 3 — 9 as follows:
CH1
(108
MHz),
CH2
(380
MHz),
CH3
(138
MHz),
CH4
(120
MHz),
CH5
(150
MHz),
CH6
(450
MHz),
CH7
(136
MHz),
CH8
(174
MHz),
CH9
(512
MHz).
Step
3:
Select
Channel
9
(512
MHz)
and
adjust
TC4
for
13V
on
the
DC
SSVM.
Step
4:
Select
Channel
1
(108
MHz)
and
adjust
T8
for
1.0V
on
the
DC
SSVM.
Step
5:
Repeat
steps
З
and
4
until
no
improvement
is
observed.
The
DC
SSVM
should
read
as
below.
108 MHz Voltage at TP5 0.9— 1.1V
380 MHz Voltage at TP5 1.2 — 2.0V
138 MHz Voltage at TPS 1.8 — 2.5V
120MHz Voltage at TP5 2.2 — 3.0V
150 MHz Voltage at TP5 3.7 — 4.7V
450 MHz Voltage at TP5 5.5 — 6.6V
136 MHz — Voltageat TP5 5.6 — 6.5V
174 MHz | Voltage at TPS 9.8 — 11.0М
512 MHz Voltage at TP5 12.5 — 13.1V