TM 11-6130-266-15
b. Use of Chart. The troubleshooting chart (d
CAUTION
below) supplements the troubleshooting chart in
Read the instructions in paragraph 5-
9 before attempting to remove or
resulted in reference to a particular item of the chart in d
replace parts.
below, refer directly to the referenced item. If no
operational symptoms are known, begin with item 1 of
5-4. Checking for Shorts
the troubleshooting chart and proceed until a symptom
a. When to Check . Check the power supply when
of the trouble is found.
the AC or DC circuit breaker trips without the load
connected, or when there is no dc output.
CAUTION
b. Conditions for Tests.
If the operational symptoms are not
known, or if they indicate the
(1) Disconnect the power supply from the
possibility of internal short circuits,
power source.
make the short-circuit checks
described in paragraph 5-4 before
(2) Disconnect the load connected to DC
applying power.
OUT receptacle J7 or J9, or DC OUTPUT receptacle J6.
c. Conditions for Tests. All checks outlined in the
Disconnect the standby battery.
troubleshooting chart are to be conducted with the power
supply connected to the ac power source and with the
dummy load across DC OUT receptacle J7.
resistance measurements indicated in paragraph 5-7.
d. Troubleshooting Chart.
CAUTION
NOTE
Do not make any resistance
measurements on the power supply
Perform the steps in the
other than those specified. Tile
organizational troubleshooting chart
multimeter battery can destroy the
in paragraph 310 before using this
transistors by excessive current
chart, unless the trouble has already
flowing through them if the
been localized.
multimeter is not connected
according to directions.
5-5. Localizing Troubles
CAUTION
a. General. In the troubleshooting chart that
follows, the procedures are outlined for localizing
In-circuit measurements made at the
troubles to a part or an assembly. The parts locations
test points or terminals on A1, A2 or
are shown in figures 5-1 through 5-9. Depending on the
A5 must be performed with the aid of
nature of the operational symptoms, one or more of the
the Extender Test Board, SM-D-
localizing procedures will l) e necessary. When trouble
943415 (fig. 5-9). To avoid
has been localized to a particular assembly, use voltage
equipment damage, be sure to shut
and resistance measurements to isolate the trouble to a
off power supply when extender
particular part.
board is being inserted or removed.
Item No.
Trouble symptom
Probable cause
Corrective action
1
AC indicator lamp DS1 fails to
a. No ac power is reaching AC IN-
a. Check continuity of the ac power
light when AC circuit breaker
PUT receptacle J3.
cord and repair or replace if
CB1 is set to ON. (230V-115V
necessary.
selector switch S1 set to prop-
b. AC circuit breaker CB1 defective.
b. Check CB1 and replace if neces-
er position.)
sary.
c. 230V-115V selector switch S1 de-
c. Check S1 and replace if necessary.
fective.
d. Transformer T1 defective.
d. Check T1 and replace if necessary.
2
NORM indicator lamp DS2 fails
a. Resistor A6A1R4 defective.
a. Check and replace A6A1R4 if nec-
to light. (AC indicator lamp
essary.
DS1 is lighted.)
b. Auxiliary supply and control as-
b. Check for +32V de between pin 11
sembly A1 defective.
and pin 17 of A1. Replace A1 if
necessary.
5-2 Change 3
