TM 11-6625-828-45
Malfunction
Probable cause
Corrective action
Defective resistors
R145
through
Replace defective resistors. Check
R148.
details of 90- to 150-cycle filter
amplifier
circuit.
Replace
defective parts.
Replace tube.
Defective electron tube V116.
Check details of meter circuits.
Defective meter circuits.
Replace defective parts.
Replace defective meters.
Replace potentiometer.
Defective meters MI01 and M102.
Replace tube.
Defective potentiometer R163.
Defective electron tube V107.
14.
%,M meter M102 needle does
not respond to 1000- MOD
control R163 movement with
Replace defective capacitors. Check
Defective capacitors C127 and C128.
MODULA- TION switch S102 set
to the 1000- position.
circuit. Replace defective parts.
Replace defective switches.
Defective switches S102 and S106.
Replace tube.
Defective electron -tube V104.
Replace tube.
Check details of
Defective electron tube V102.
modulator circuit.
Replace
defective parts.
Replace tube.
Defective electron tube V116.
Check details of meter circuits.
Defective meter circuits.
Replace defective parts.
Replace defective meter.
Defective meter M0I or M102.
(3) Measure the voltage at the orange
2-6.
Signal Substitution
wire terminal of capacitor C160. The voltage should
a. General. Signal substitution procedures
help to localize troubles to a circuit or stage in the test
(4) Measure the voltage at the yellow with
set. An externally generated signal is substituted for the
red-trace wire terminal of capacitor C161. Volt- age
signal normally present in each stage.
The test
should be between 185 and 215 volts de.
equipment required for the tests below is listed in
2-7.
Isolating Trouble Within Stage
b. Space Heater Circuit.
When trouble has been localized to a stage, either
through operational checks or signal substitution (para 2-
(1) Connect Variable Power Transformer
6), use the following techniques to isolate the defective
CN-16A/U to a source of power and connect Power
part:
Cable Assembly CX-337/U between the CN-16A/U and
test set POWER INPUT 115 V 60- receptacle J106.
a. Test the tube involved using Electron Tube,
Test Set TV-7/U or by substituting a similar type tube
(2) Adjust the CN-16A/U for a 115-volt
which is known to be operating norm- ally.
input to the test set and set POWER-STANDB7 switch
b. Take voltage measurements at the tube
S106 at STANDBY. Check to see that space heater
sockets (fig. 4-12) and other points related to the stage in
resistors R193, R194, and R195 warm up.
question.
c. Power Supply.
c. If voltage readings are abnormal, take
(1) Use the CN-16A/U to apply an input
resistance readings to isolate open and short circuits.
voltage of 115 volts to the AN/ARM-5A from multimeter
Also, refer to the de resistances of transformers and
TS-352B/U. Set POWER-STAND BY switch at POWER.
to trace circuits and to isolate the faulty component.
the output voltage at pin 3 of high-voltage regulator
V114. The voltage should be between 390 and 420 volts
2-8.
de.
coils in the test set are listed below:
2-6