Lesson 3
SYSTEM TROUBLESHOOT AN/GRC-193A RADIO SET,
AND REPAIR
OBJECTIVE
Upon completion of this lesson, you will be able to system troubleshoot an AN/GRC-
193A radio set to a defective component, cable, or accessory and fix, replace, or
initiate action for repair at a higher level of maintenance.
REFERENCES
This lesson is based on TM 11-5820-924-13 and other material approved for US Army
instruction. However, development and progress render the text continually subject
to change. Therefore, base your examination answers on material presented in this
lesson rather than on individual or unit experience.
14. INTRODUCTION. The operational check (EPC) indicates that everything works as
it is intended to. To keep the AN/GRC-193A operating reliably, you must know how
to troubleshoot and repair the set when it does break down. You know now that an
AN/GRC-193A consists of four major components--an antenna system, two audio
accessories (handset and headset), a CW key, and eight interconnect cables with a
power source (vehicle battery) or (DC power supply PP-7333/GRC) used for bench
mounting.
15. MAJOR COMPONENT DIRECT EXCHANGE.
Once you have isolated a malfunction to a
major component, you must make out DA Forms 2402 (Exchange Tag), 2404, and 2407
(Maintenance Request) and evacuate the malfunctioning component to your direct
support unit for direct exchange (DX).
Isolation of a fault to a particular
component can be very difficult with an interconnected system of components. This
i why it is necessary to be very aware of all indicators provided in the AN/GRC-
193A.
16. REPLACEABLE AND REPAIRABLE ITEMS. Fuses, cables, and audio accessories can be
replaced by organizational maintenance and, in some instances, repaired. A problem
located in an H-l89 handset can probably be repaired, as can a problem in an H-140
headset; but a problem in an H-250 handset requires replacement. Figure 11 shows
interconnect cabling for the AN/GRC-193A. We notice that W1, W5, and W8 cables are
coaxial RF cables and can be checked with an ohmmeter. The W6, audio, and W3 power
cables can be checked easily with the ohmmeter. However, W2 and RT control cables
require careful checking, because the different connectors at each end are not
wired pin-for-pin (pin N at the AM-6545 of the W2 cable goes to pin T at the
AM-6879 end).
See Table 6, which has a list of pin assignments for W2 and RT
control cables.
25
Previous Page
