TM
11-6625-1683-15
CHAPTER 5
FUNCTIONING
5-4. 115 VAC INPUT POWER
5-1. General
(fig. 9-11 x )
Test Panel SB-3004/PPS5 consists of 23
individual and independent circuits (fig. 9-11
a. One side of the power line entering
x ) a compact and integrated assembly
through the power cable and pin 1 of terminal
for testing the radar set or its components. It
board TB1 is fed through interlock switch
contains power converter units, identical with
S 2 8 - B into INPUT POWER switch S1-A.
those in the radar set, thereby providing con-
With the INPUT POWER switch at AC ON,
venient sources of the voltages required for
connection is established to MAIN POWER
energizing removed components of the radar
push breaker CB1. This push breaker provides
set. Test jacks provide access to circuit test
overload protection. In the closed circuit con-
points; connectors and test cables provide cou-
dition, push breaker CB1 completes the circuit
pling to the radar set components undergoing
of one leg of the 115 VAC input power line
test.
leading to an internal power converter.
b. The other leg of the 115 VAC power input
5-2. INPUT POWER Circuit
cable connects to the internal power converter
The input power required to energize the
through pin 2 of terminal board TB1 and IN-
equipment may be either 6 volts dc at 9 am-
PUT POWER switch S1B. Each leg of the
p e r e s (obtainable from Battery Box CY-
115-volt ac power circuit enters the power con-
3 8 7 1 / P P S - 5 or P o w e r Supply PP-4450/
verter through radio frequency ( rf ) filters, des-
PPS-5) or 115 volts act 50 to 1,000 Hz, at 0.9
ignated FL1 and FL2, respectively. These fil-
ampere.
t e r s contained within the power converter
shield, serve to prevent emission of rf interfer-
5-3. 6 VDC INPUT POWER
ence signals that might be generated by the
(fig. 9-11 x )
converter circuit. Each filter consists of a pi-
Power enters through connector J1, pins 2
network offering a high order of attenuation
and 7 carrying 6 volts; pins 3, 4, and 5 con-
to frequencies above 1 kHz.
nect the positive side to ground. The negative
c. After passing through the rf filters, the
side (6 volts) feeds through interlock switch
ac input is applied to a bridge rectifier consist-
S28A to INPUT POWER switch S1-C. The
ing of four 1N3190 diodes (CRI, CR2, CR3,
INPUT POWER switch controls power mode
and CR4 ). The negative side of the dc output
selection and, in the DC ON position, supplies
from the rectifier is floating. The positive side
operation voltage to the various circuits re-
of the dc output passes into a choke input filter
quiring this potential. Overload protection in
circuit containing inductor L1 and six capaci-
this circuit is provided by RCVR-XMTR switch
tors, Cl through C6, connected in parallel. This
breaker CB4. Pins 1 and 6 supply synchroniz-
represents a total capacitance of 216 micro-
ing signals (4,000 Hz, 8 volts) from block 700
farads ( uf ). The voltage at the output of the
to Power Supply PP-4450/PPS-5.
5-1
AGO 7918A
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