9-17. Organizational Troubleshooting Chart
Checks and corrective measures
No input voltage
a. Circuit breaker CB1 tripped
a. Reset circuit breaker.
b. No Output voltage
b. If circuit breaker is not tripped, cheek
input voltage and connections.
High output voltage
a. Check input voltage; make output
a. Input voltage high and/or output voltage
voltage adjustment (para 9-18c).
b. Shorted silicon controlled rectifier
b. Higher category maintenance required.
c. Resistor assembly Z1 defective.
c. Higher category maintenance required.
Low output voltage
a. Replace defective fuse (para 9-18b).
a. Control unit fuse F1
b. Adjust output voltage(para 9-18c)
b. Output voltage improperly adjusted.
c. Press connector board tightly into printed
c. Connector J1 improperly installed on
printed circuit board A1.
d. Connector J1 defective
d. Higher category maintenance required.
e. Resistors R1, R3, R4, R5, or R8 defective
e. Higher category maintenance required.
f Transformer T5 defective
f. Higher category maintenance required.
g. Resistor assembly Z1 defective
g. Higher category maintenance required.
LINE lamp does not light, and
Defective LINE lamp DS1
Replace LINE lamp (para 9-18a).
output voltage is normal.
(2) Apply power to the unit with the circuit breaker
set to OFF.
9-18. Repairs and Adjustments
(3) Energize the unit by setting the circuit breaker
a. Replacement of Indicator Lamp.
to ON (up).
(1) Unscrew pilot lamp lens.
(2) Press in on the pilot lamp and turn it
Allow a 10- to 30-minute warmup period
counterclockwise to unlock.
when a close setting is necessary.
(3) Pull defective lamp out and replace it with a
(4) Remove the protective cap on the OUTPUT
new one. Push the lamp in and twist it clockwise to
VOLTAGE control, loosen the locknut, and turn the
control until the desired output is observed on
(4) Reinstall pilot lamp lens.
Multimeter AN/U S M-223.
b. Replacement of Control Circuit Fuse.
(5) Connect a load to the OUTPUT receptacle and
(1) Unscrew fuse cap (front panel).
energize the load.
(2) Remove fuse from cap.
(6) Observe that the output voltage remains within
(3) Reinstall new fuse and cap, and twist
the rated accuracy (para 9-3).
clockwise to lock.
(7) Lock the adjustment by tightening the locknut;
c. Adjustment of Output Voltage.
replace the protective cap.
(1) Connect Multimeter AN/USM-223 to the