TM 55-4920-402-13&P
CHAPTER 3
AVIATION UNIT MAINTENANCE INSTRUCTIONS
Section I. PREPARATION FOR USE, STORAGE, AND SHIPMENT
3-1. Preparation for Use.
a. Upon receipt of the VIBREX, carefully open the
shipping container.
NOTE
Retain the shipping container. The VIBREX
may be damaged in shipping and, therefore,
must be returned through proper channels.
b. Open the Carrying Case and perform the following
check
(1) Check contents against packing slip.
(2) Check for obvious damage; i.e., dents, chips,
crocks, etc.
3-2. Preparation for Storage. Use the following
procedure when preparing the VIBREX for storage:
a. Place the Tester, Accelerometers, Magnetic
b. Place the Balancer, Strobex, and Gram Scale in
their proper compartments in the Carrying Case (fig. l-l).
c. Close Carrying Case.
3-3. Preparation for Shipment. Perform all steps in
paragraph 3-2 and the following
a. Place Carrying Case in shipping container.
b. Record missing or damaged components on the
appropriate forms.
c. Return VIBREX through proper channels.
3-3A. For general technical information on preparation
for storage and shipment, refer to TM 1-1500-204-23
(series). For regulatory requirement pertaining to equip-
ment placed in administrative storage, refer to AR 750-1.
Pickups, Brackets, and Cables in the top compartment of
the Carrying Case (fig. l-l).
Section II. OPERATIONAL CHECKOUT
NOTE
The VIBREX is performance checked and
calibrated prior to leaving the factory. How-
ever, the following procedures should be
performed to ensure that no damage to internal
components has occurred during shipment.
3-4. Test Preparation.
Perform the instructions in this
section prior to actual use of the VIBREX. Personnel
should become thoroughly familiar with the entire
procedure before attempting the test.
CAUTION
Extreme care should be exercised when using
the VIBREX test set. This unit contains
delicate electronic components and assemblies
which may be easily damaged if subjected to
physical abuse due to improper handling.
a. Test Requirements. Testing of the following
VIBREX items is required
(1) Balancer
(2) Strobex
(3) Magnetic Pickup 3030AN
(4) Accelerometer 4177B
(5) Associated cables
NOTE
Testing of the VIBREX requires 24 to 30 vdc
power source. This can be obtained from a
battery, aircraft source or portable DC power
supply of at least 3 amps minimum.
b. Test Setup. Refer to figure 3-1 for VIBREX test
setup.
CAUTION
Ensure all cabling is correctly installed and
equipment is connected to a stable 28 vdc
source.
3-5. Balancer Checkout. Testing of all functions of
the Balancer is accomplished by the Tester. If the follow-
ing performance checks are not within specifications,
perform paragraph 3-8 below to isolate if the Balancer
unit is at fault.
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