TM 11-6130-381-14
more) may damage the transistor under
the exact nature of the fault. The operating
procedures (para 2-6), with the normally expected
test. As a general rule, the RX1 range of
any ohmmeter should not be used when
indications called out in the procedures, provide
testing low-powered transistors.
good operational checks. If an abnormal indication
c. Iso/ation. After the fault has been localized
or result is observed during the operational check;
by using the troubleshooting chart, voltage and
t h e n perform checks and corrective actions
resistance measurements and waveform checks
enumerated in the troubleshooting chart (para
should be made to isolate the defective component.
A deviation of any appreciable amount from the
resolve the problem, a higher maintenance repair
activity is required.
indications of paragraph 5-5 indicates a faulty
NOTE
part .
The troubleshooting chart lists symptoms
d. Resistor, Capacitor, and Inductor Color Code
C i a g r a m . A color code diagram for resistors,
of common troubles and give (or reference)
corrective measures. Such a chart cannot
capacitors, and inductors (fig. FO-2) provide
include all the trouble symptoms that may
pertinent resistance, voltage rating, and tolerance
information.
occur; repair personnel should use the chart
as a guide in analyzing symptoms that
may not be listed.
5-3 show component locations of parts,
CAUTION
subassemblies, a n d assemblies of the battery
Before using any ohmmeter to test tran-
charger.
sistors or transistor circuits, check the
NOTE
open circuit voltage across the ohmmeter
When making resistance checks, be careful
test leads. Do not use the ohmmeter if the
of the test lead polarity. If the resistance
open circuit voltage exceeds 1.5 volts.
reading is low, always reverse the test
A l s o , since the RX1 range normally
leads because of the diode action through a
connects the ohmmeter internal battery
transistor. If a normal resistance is read
after the kids are reversed, the stage is
directly across the test leads, the com-
paratively high current (50 milliamperes or
operating correctly.
Figure 5-1. Battery charger component locations, rear of front panel.
5-2
