TM 1-1520-265-23
WARNING
Electrical equipment shall not be operated in areas where combustible gases or vapors may be
present, unless the equipment is explosion-proof.
a.
If instrument is operated using AC power, use a grounded power cord.
b.
Turn power OFF before connecting or disconnecting transducer cable or power cable.
1.4.12.2
Ultrasonic Instrument Standardization. The ultrasonic instrument used in ultrasonic inspection procedures
described throughout this manual is listed in Table 1-7. Reference blocks, instrument settings, and standardization
instructions for the ultrasonic instrument are included in the individual ultrasonic inspection procedures. Because of
varied circumstances under which the inspections may be performed, instrument settings, as they are given in this
manual, should be considered typical. Slight adjustment to the settings may be necessary to achieve the desired CRT
presentation. Illustrations representing typical CRT presentation will, in most cases, include reference signals
representing initial pulse, transducer, and/or wedge echoes that have been moved off the scope to make room for
relevant indications. An effective ultrasonic inspection will depend largely upon the proper handling of the transducer;
therefore, the following steps are recommended:
a.
Clean ultrasonic transducer with a low-lint cloth, MIL-C-85043 or equivalent. Clean all contact surfaces when
using a wedge or delay block. Apply couplant to these contact surfaces and carefully tighten the assembly prior
to test.
NOTE
Scratches or similar surface blemishes remaining on the transducer or wedge may give false
indications.
b.
Use prescribed or equivalent couplant and in sufficient quantity to achieve proper coupling. The use of lubricants
containing graphite, silicones, and glycerines is prohibited.
c.
Apply adequate pressure to keep transducer in contact with part.
d.
Use moderate speed for transducer search pattern. If transducer movement is too fast, a flaw could be passed
over without a proper indication.
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