troubleshooting chart (para 5-4 d) lists symptoms
5-1. General Instructions
of c o m m o n t r o u b l e s a n d g i v e s corrective
Troubleshooting at the general support main-
measures (or references). Such a chart cannot
tenance category includes all the techniques
include all troubles symptoms that may occur;
outlined for organizational maintenance and any
therefore, the repairman should use this chart as
special or additional techniques required to isolate
a guide in analyzing symptoms that may be
troubleshooting chart to be used by the repair-
5-3. Test Equipment Required
The test equipment required for troubleshooting
a. General. The first step in servicing a
defective tester is to localize the fault, which
means tracing the fault to the defective circuit
responsible for the abnormal indication. The
a. General. The troubleshooting chart ( d
second step is to isolate the fault, which means
below) outlines procedures for localizing troubles
l o c a t i n g the defective part or parts. Most
and for isolating troubles within the various
defective parts, however, must be isolated by
c h e c k i n g the metering and meter circuits,
location. Refer to the schematic diagram (fig. FO-
2) to identify circuit components. Depending on
b. Localization and Isolation. The first step in
the nature of the operational symptoms, one or
tracing trouble is to locate the circuit or part at
m o r e of the localizing procedures will be
fault by the following methods:
necessary. When trouble has been localized to a
(1) Visual inspection. The purpose of visual
inspection is to locate faults without testing or
measurements to isolate the trouble to a par-
measuring circuits. All meter indications or other
visual signs should be observed and an attempt
b. Use of Chart. When an abnormal symptom
made to localize the fault to a particular part.
i s observed in the equipment, look for a
(2) Operational test. O p e r a t i o n a l t e s t
description of the symptom in the S y m p t o m
frequently indicates the general location of
column and perform the corrective measure given
trouble. In many instances the test will help in
in the Corrective measures column.
determining the exact nature of the fault. The
c. Conditions to Test. All checks outlined in
the troubleshooting chart are to be conducted
contains a good operational t e s t .
using an inverter known to be in good operating
d. Troubleshooting Chart.
1. 28V. ON indicator lamp does not
a. Check for input voltage.
a. No dc power is applied to tester.
b. Check switch; replace if defective.
light when D. C. POWER switch is
b. Defective switch.
set to ON.
2. Indication on D. C. VOLTS meter
Defective meter M102.
Replace meter M102.
M102 differs from voltage present
3 . With D. C. POWER switch ON
a. Defective M101.
a. Replace M101.
b. D e f e c t i v e r e l a y s K 1 0 1 , K 1 0 2 ,
and load applied to inverter under
b. Replace relays K101, K102, K103,
test, no indication on D. C. AMPS
c. Remove and replace microswitch
( l o c a t e d in back of D. C. AM-
METER RANGE selector).
d. D e f e c t i v e D . C . A M M E T E R
d. Replace switch S107.