CIRCUIT SELECTOR Switches

11-6625-467-34

a. -27.5-Volt Metering Circuit. Resistor A8R10 is

despike rectifier output to the positive side of the

the series meter multiplier resistor. When POWER

T E S T METER and ground to the negative side.

SELECTOR switch S1 is in the -27.5V position, re-

R e s i s t o r A7R12 is adjusted so that a 40-volt pulse

sistor A8R10 connects the 27.5-volt power supply

output from the power supply (including the dc level

through contacts 13 and 12 of S1C FRONT TO TERMINAL

above ground) produces an 80 percent TEST

4 of PRESS TO MONITOR VOLTAGE switch S10.

METER reading.

S w i t c h S1C rear grounds S10-1.Pushing S10 con

2-44. CIRCUIT SELECTOR Switches

nects -27.5 volts to the negative side of the TEST

(fig, FO-31

METER and ground to the positive side. The TEST

a. General. The CIRCUIT SELECTOR switches

METER indicates 65 percent with -27.5 volts ap-

on the test set perform the switching necessary for

plied to meter multiplier resistor A8R10.

t e s t i n g the AN/ARC-54 modules. Figure FO-3 con-

b. +25.5Volt Metering Circuit. T h e + 2 7 . 5 v o l t

sists of a simplified schematic diagram showing the

metering circuit is similar to the -27.5 volt circuit

four CIRCUIT SELECTOR switches, the AN/ARC-

d i s c u s s e d in a above. Resistor A6R2 is the meter

54 module connectors, and the functional test set

multiplier resistor. When POWER SELECTOR

c i r c u i t s . Tables 2-1 through 2-8 of this manual

switch S1 is in the NORMAL or EXTTERNAL posi-

describe the function of each CIRCUIT SELECTOR

supply output through contacts 2 or 5 and 18 of S1C

switch wafer for the program settings in the

REAR TO TERMINAL 1 of PRESS TO MONITOR

o p e r a t i n g procedures and the operator's PMCS

V O L T A G E switch S10. Switch S1C front grounds

c h a r t in TM 11-6625-467-12. Figure FO-3 sup-

S10-4. pUSHING S10 connects +27.5 volts to the posi-

p l e m e n t s this information with switch contact

t i v e side of the TEST METER and ground to the

numbers and circuit card terminal numbers which

negative side.The TEST METER indicates 65 per-

are very helpful in troubleshooting the test set.

of CIRCUIT

SET,ELECTOR

Arrangement

cent with +27.5 volts applied to multiplier A6R2

Switch Schematic Diagram. Figure FO-3 does not

c. +500 Volts Metering Circuit. Because both the

show point-to-point wiring of the test set. The

+ 5 0 0 and +250 volt outputs are derived from the

diagram shows the logical routing of test set signals

same power supply, only the +500 volts is the metered

and gives functional names to each signal path. The

Resistor A7R13 and A7R15 comprise a voltage

front panel controls and other components asso-

divider across the +500 volts supply. The voltage at

ciated with the functional circuits but not located on

the junction of these two resistors is reduced to ap-

the circuit cards are shown on the extreme right

p r o x i m a t e l y 85 volts. When POWER SELECTOR

hand side of figure FO-3.

switch S1 is in the HIGH VOLTAGE position, re-

c. Using C I R C U I T SELECTOR Switch Sche-

s i s t o r A7R14 (meter multiplier resistor) connects

matic Diagram. The diagram can be used as an aid in

the 85 volts through contacts 3 and 18 of S1C rear to

troubleshooting the test set (para 3-6 and 3-7) or to

terminal 1 of PRESS TO MONITOR VOLTAGE

analyze the circuit operation.

switch S10. Switch S1C front grounds S10-4. Push-

(1) If the 30-megahertz oscillator circuit is to

ing S10 connects the divider circuit to the positive

be turned on and the output level set to some speci-

side of the TEST METER and ground to the nega-

t i v e side. The TEST METER indicates 65 percent

fied reading on the TEST METER, refer to figure

with 500 volts applied to the voltage divider.

FO-3 and notice that the HIGH FREQ AMPL con-

trol connects to pin B of XA1l through two switch

d. Despike Metering Circuit. The despike meter-

sections, S3E-1 and S5D-8. The lower section of fig-

ing circuit measures the output of the +27.5 volt

ure FO-4 shows the 30 MC OSC LEVEL CONT

power supply when the test set is operating in the

OUTPUT connected to S3E-1 and S5D-8. This con-

despike mode. Diode A7CR6 rectifies the pulse out

dition indicates that when S3 (CIRCUIT SELEC-

put of the +27.5 volt power supply. Capacitor A7C4

TOR A) is in position 0 (the CIRCUIT SELECTOR

filters therectified output. The voltage at the junc-

tion if A7C4 and diode A7CR6 is a dc voltage ap-

position will always be one number less than the

switch contact number), the HIGH FREQ AMPL

proximately equual to the peak voltage of the pulse

output of the power supply. Resistor A7R12 is the meter

control output (R2-2) connects to the 30-megahertz

series with adjustable resistor A7R12 is the meter

oscillator through S3D and S3E. A second path

m u l t i p l i e r resistor. When POWER SELECTOR

exists through switch S5 (CIRCUIT SELECTOR C)

switch S1 is the DESPIKE position, the two re-

when S5 is in position 7. Now refer to HIGH FREQ

sistor connect the despike rectifier output

AMPL control R2 (figure FO-3, extreme right hand

contacts 4 and 18 of S1C rear to terminal 1 of PRESS

side); the movable arm is shown to connect to the

TO MONITOR VOLTAGE switch S10. Switch S1C

two places discussed above, S3D-1 and S5C-7, 8.

f r o n t grounds S10-4. Pushing S10 connects the

(The connection to S5C7 is used for another function

2-82