Cable Assembly, Special Purpose, Electrical CS-4655/GRC

TM 11-5820-498-35

required 13-volt output from the voltage regula-

volts that appears across resistor R19 is applied

tor.

to pin M of connector J2.

c. ANT. FREQ. CONTROL Switch S2. T h e

(2) Bias for Q4 is supplied from a voltage-

+25-volt dc input at pin J of POWER INPUT

dividing network composed of R9, R10, R11, and

connector J3 is applied through PWR circuit

R19 connected between the collector of Q3 and

creaker CB1 and switch S2 to the MX2799/VRC

ground. Diode CR1 references the emitter of Q4

of the AT912/VRC or to MX-6707/VRC of the

to ground. Diode CR2 references the base of Q4

AS-1729/VRC, whichever is connected to the

to the + 13-volt output. Regulating action is de-

AM2060(*)/GRC. Switch S2 is set to the posi-

scribed in (3) below.

tion corresponding to the operating frequency of

(3) If the input voltage to Q3 decreases, the

the associated receiver-transmitter. Capacitors

13-volt output decreases. Capacitor C1, charged

C1 through C7 bypass radio frequency (RF) from

to the 13-volt level, will begin to discharge as the

the MX2799/VRC or MX6707/VRC to ground.

output voltage drops, tending to maintain a con-

stant output until the regulating action occurs.

2-11. Cable Assembly, Special Purpose,

As the output voltage decreases, the voltage drop

Electrical CS-4655/GRC

across R9, R11, and R19 decreases, reducing for-

(fig. 3-5)

ward bias on Q4, which will decrease its emitter-

The CX-4655/GRC (9 or 11 inches long) and the

to-collector current flow. The reduced emitter-to-

A M - 2 0 6 0 ( * ) / G R C comprise the OA-3633(*)/

collector current of Q4 reduces the voltage drop

GRC. The CX-4655/GRC is provided with two ca-

across resistor R6, increasing the forward bias of

Q3. Emitter-to-collector current flow in Q3 will

ble connectors either of which is connected to

increase, decreasing emitter-to-collector resist-

the SET POWER connector on the

ance. The voltage drop through Q3 will decrease

AM2060(*)/GRC; the other end of the cable is

and allow the output to return to the desired level

connected to POWER connector J3 on the re-

of 13 volts. If the supply voltage increases to the

ceiver-transmitter. The cable carries power, con-

normal 25.5-volt level, Q4 will decrease the for-

trol circuits, and audio signal circuits between

ward bias on Q3 to maintain the constant 13-volt

the AM2060(*)/GRC and the receiver-transmit-

output. Resistor R10 is adjusted to produce the

ter.

2-13