TM 11-6625-1683-15
CHAPTER 6
TROUBLESHOOTING
Section 1. GENERAL TROUBLESHOOTING INFORMATION
b. Localization. Test Facilities Kit MK-
Warning: High voltages are present in the
980/PPS5 consists of an array of test cir-
MK-980/PPS-5, and safety precautions should
cuits in addition to power sources for ener-
be observed. Potentials of 2,000 volts appear at
gizing the circuits with the various voltage
the CRT TEST push switch and at contact 13
of CRT TEST connector J16 when the push
levels required. It also provides an accessory
switch is depressed.
kit containing cables and couplings for inter-
connecting t h e individual MK-980/PPS-5
test circuits with the corresponding circuits
6-1. General Instructions
of the AN/PPS-5 radar set. Except for the
Troubleshooting at general support includes
power requirement dependency involving the
all the techniques outlined for organizational
power converters, each test circuit is an inde-
maintenance, and any special or additional
pendent unit; therefore, localization of faults
techniques required to isolate a defective part
will be self-evident during operational use of
and effect restoration of the equipment to
the equipment or in the course of sequential
service. Paragraphs 6-4 through 6-10 present
maintenance checkout procedures.
the individual circuit units that comprise the
MK980/PPS5 and the troubleshooting pro-
t h r o u g h 6-10 and the associated trouble-
cedures applicable to each circuit unit. Where
shooting charts will indicate the specific wave-
circuit or functional interrelationships are in-
forms, voltage, or resistance readings that
volved, the techniques for localizing and iso-
should be obtainable at significant points in
lating faults are described.
each test block. Deviations from the normal
will define the component or other circuit ele-
6-2. Organization of Troubleshooting
ment causing any malfunction. Frequently,
Procedures
visual inspection will disclose a source of
trouble either because of thermal discolora-
a. General. The initial requirement for a
tion or mechanical abnormality.
logical service procedure is localization of the
faulty area of operation. This may be deter-
d. Resistance Measurements. Although tran-
mined by the nature and area of the defi-
sistorized circuits are utilized for power sup-
ciency or abnormality. Once this is established,
ply purposes, these circuits are de-isolated
the next step is to isolate or locate the specific
from all other circuits wherein ohmmeter mea-
cause of the abnormality. This may be a defec-
surements would be applicable. Therefore, no
tive component or the result of some mechan-
special precautions are required in the use of
ical failure. Primarily, isolation of a fault will
t h e ohmmeter with respect to polarity or
require voltage or resistance readout. The
range unless expressly stated.
normal operational use of the MK-980/PPS-5
e. Voltage Measurements. Unless otherwise
will, in a large measure, indicate the location
indicated by directions for a specific measure-
and probable nature of the defect.
6-1
AGO 7918A
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