Under ambient operating temperatures and temperatures below approximately 140 F (60 C)

TM 11-5820-695-35

opens deenergizing air flow fault relay 3A1K2. If the air

CV-3633/GRC-144(V) modules through the various

flow fault relay is energized because of adequate air

terminal board and connector pins shown in figure 2-33

flow or deactivated by thermostat 3A7S1 when the CV-

and is used to provide the bias voltages for transistor

3633/GC-144(V) operating temperatures; are above

and integrated circuit operation, closure voltage for relay

approximately 158 (70 ); the status panel lamp

operation, illuminates all monitor and fault indicators

3A80S2 illuminates AIR FLOW fault indicator monitor

and provides operating voltage for electronic frequency

green. When the air flow fault relay is deenergized

converter tunnel diode amplifier 3A2A1 and local

because of inadequate air flow the status panel lamp

oscillator 3A2A3. The +28 Vdc is also switched by

3A80S4 illuminates AIR FLOW fault indicator monitor

amplifier-multiplier 3A5 thermostat 3A5S2 to illuminate

red. Refer to paragraph 3-87 for a complete description

status panel 3A8 TEMP indicator green or red indicating

of alarm monitor 3A1 circuit functioning.

amplifier-multiplier 3A5 temperature normal and alarm

conditions respectively. In addition, the air flow sensing

switch 3A7S2 heating element is powered by +28 Vdc

d. Mounted on the electrical equipment chassis

through rfi filters 3A7FL4, 3A7FL5 and 3A7FL8 that

3A7 are the necessary components to rf couple

prevent unwanted interference of electromagnetic

operating modules of the CV-3633/GRFC-144(V) and

radiation of radio frequency from the opening or closing

antenna system together (fig. 2-34). The transmit and

of thermostat 3A7S1, air flow sensing switch 3A752, or

receive paths from Transmitter, Radio T-1054(P)A/IRC-

status panel 3A8 OSC TEMP indicator PUSH TO TEST

144 and Receiver, Radio R-1467(P)A/GFC-144 to and

switch 3A8DS1.

from the antenna system through the electrical

equipment chassis 3A7 components are described in (1)

c. Under ambient operating temperatures and

and (2) below.

temperatures below approximately 140 F (60 C),

thermostat 3A7S1 is closed applying +28 Vdc to a

(1) The C-band 4.8 to 5.0 GHz output from

heating element in air flow sensing switch 3A7S2.

Transmitter, Radio T-1054(P)A/GRC-144 is applied to

When the air flow sensing switch 3A7S2 temperatures

the CV-3633/GRC-144(V) amplifier multiplier 3A5

are maintained by adequate air flow from the R-

circuits. Amplifier multiplier 3A5 is a fixed tuned

1467(P)A/GRC-144 blower 2A1561, airflow sensing

broadband amplifier that contains a X3 multiplier 3A5A1

switch is closed applying +28 Vdc to alarm monitor 3A1

and impatt amplifier circuits and a constant current

air flow fault relay 3A1K2 through rfi filter FL8-A3 and

source 3A5A8. The amplifier-multiplier circuits up-

connector 3AXAl pin 14. If adequate air flow from

convert the 4.8 to 5.0 GHz

blower 2Al581 is not maintained, air flow sensing switch

Change 6 2-127