*TM-11-5821-284-34
b.
The electrical subassemblies of antenna AS
1-8.
Historical Revisions to Equipment
2285/ARC have been revised during the history of antenna
a.
No external appearance or major operational
AS-2285/ARC as indicated in the table below.
differences exist between procurements of antenna AS
2285/ARC
MNC EFFECTIVITY LISTING
Ref des
MCN effectivity
Description of change
A1CRIO
101
Changed to 1N748A
A1CR25
101
Deleted and substituted insulated bus wire
A1CR28
101
Changed to 1N746A
A1R16
101
Changed to 2 7K, 1/4 watt
A1R28
101
Changed to 560K, 1/4 watt
A2R1
101
Changed to 10 ohm, 1/4 watt
A2R4
101
Changed to 680 ohm, 1/4 watt
A2R5
101
Changed to 390 ohm, 1/4 watt
Gear A, gear B, shaft
101
Changed gear A from steel to aluminum, and shaft from 1/8" diameter
Interchangeable with older models If all parts are ordered
Plate, shunt Inductor L4
101
Changed width of plate to improve vswr performance
Radome
101
Changed element shape to improve vswr performance
A1R5
200 (approx)
Changed t6 51K, 1/4 watt 5%
Busing, capacitor
350 (approx)
Changed to improve operational margin at 24 volts dc
Motor, B1
600
Changed to improve operational margin at 24 volts dc Interchangeable
with older models If AIQI through AIQ3 are changed
CR2
600
Added zener diode 1N3036B to prevent instability under high-power
conditions. (Labeled CR3 in 437S-IB only.)
A1CR27
600
Deleted.
A1R34 through A1R36
600
Changed to 820 ohm
A1R37 through A1R39
600
Changed to 560 ohm
A1R43
600
Value may vary from 120 ohm, I watt to 220 ohm, 1/2 watt with 150
ohm, 1 watt being nominal Choice of value is made to obtain
acceptable vswr and tumnng stability If resistance is increased vswr
improved, but instability may result A IR43 replacements should be
same value as original unless specific problems have occurred.
A1R34 through A1R36
657
Changed to 27K, 1/8 watt, 10%
A1R37 through A1R39
657
Changed to 16K, 3 watt, 5%
A1CR1
775
Changed to 1N4383
C2
1200
Added 0.1 microfarad 25 wvdc capacitor from FLI-2 to FL5-2
Fine tune ferrite cores
1200
Changed fine tune ferrity cores support method
RF on circuit
1650
Changed RF on circuit coupling method
Motor, B1
1700
Added inertlal damping device to motor
A1, pointed circuit board
1740
Added A1CR29 and circuit from AIA3-12 to AIA4-2, and deleted circuit
from A1A3-12 to A1A4-14 Required addition of R2 when retrofitting
units prior to MCN 1740
A1Q13
1900
Changed to 2N956
A2R4
1900
Changed to 1K, 1/4 watt
A1R24
2155
Changed to 1.5 megohm, 1/4 watt.
A1R5 and AIR6
2752
Changed to 54 9K, 1/8 watt, 1.%
Fine tune ferrite cores
2865
Changed fine-tune ferrite cores support method
R2
2956
Added 3 9 megohm, 1/4 watt resistor
A1R24
2956
Changed to 820K, 1/4 watt
A1R28
2956
Changed to 1.5 megohm, 1/4 watt
C1
3200
Changed to Collins part no 922-0588-010, (higher reliability, longer life
unit)
A2C1 ad A1A1C11
437S-1B,
Changed A2CI from 6 pF to 4 pF
REV AD
437S-1C, REV H
Added A1A1C11
1-2