the upper spring. Place all components on a clean,
a. Inspect the bobbin assembly for loose or dam-
lint free cloth.
aged terminals, loose or broken weld connections,
or damaged threads. Inspect the coil carefully for
h. Using non-magnetic tweezers, carefully remove
damaged insulation or broken windings.
the sleeve from the bobbin assembly and place on a
clean. lint-free cloth.
b. Using a microscope (10 power), inspect the sur-
face of the magnet, and the bore of the magnet sleeve
i. Cable assembly can be removed from cover by
for cracks, nicks, scratches, or foreign particles.
loosening set screw on underside of cover.
c. Inspect the bearing surface of the magnet sleeve
for evidence of rubbing, binding, or excessive fric-
transducer except cable assembly, as follows:
tion. Replace magnet assembly or magnet sleeve with
new parts even if very slight defects are noted.
d. Inspect the cable assembly connector for loose
Do not ultrasonically clean the bobbin assem-
pins, and the case for damaged threads.
bly, or the coil insulation will be damaged.
1-86. COMPONENT TESTING. Individual component
a. Flush sleeve and the bore of the bobbin assem-
testing is not required. All system testing is covered
bly with Freon, and bake for one hour at 600oF. Re-
in paragraphs 1-66 through 1-69.
move from oven and immediately place in a dry area.
1-87. REPLACEMENT OF PARTS. All parts which
b. Using dry nitrogen, blow any lint from the sleeve
do not meet the inspection requirements of paragraph
and bore of the bobbin assembly.
1-85 should be replaced with new parts. Any time
replacement of parts is indicated, all new parts should
NOTE
be cleaned and processed as described in para-
graph 1-84.
It is recommended that the magnet assembly
be demagnetized before cleaning to prevent
1-88. LUBRICATION. Lubrication is not required.
attraction of foreign particles.
1-89. REASSEMBLY. Reassemble the transducer as
c. Spray the magnet assembly with Freon TMC for
follows :
approximately 30 seconds.
d. Ultrasonically clean the magnet assembly in
Reassembly should be performed in a dry at-
Freon TMC for 5 minutes.
mosphere using non-magnetic tweezers. Do
not touch internal parts with hands. If parts
e. Remove magnet assembly from ultrasonic cleaner
have been in contact with the skin, clean the
and spray with Freon TMC for approximately 30
parts as described in paragraph 1-84 before
seconds.
reassembly.
f. Ultrasonically clean the magnet assembly in
a. Place sleeve in bobbin assembly bore.
methyl alcohol for 5 minutes.
b. Place upper compression spring in the sleeve,
g. Vacuum bake the magnet assembly for a mini-
then place the magnet assembly in the sleeve. Insert
mum of 15 minutes at 140F at one millimeter of
the lower compression spring in the sleeve.
pressure.
c. Place bobbin assembly in case, being very care-
h. Bake the magnet in a 500F oven for 8 hours
ful not to allow the springs, magnet assembly, or
minimum.
sleeve to fall out of place. Place case assembly on
torque plate and carefully screw the bobbin into the
i. Ultrasonically clean the case, springs, and gas-
case, using the spanner wrench. Torque to approxi-
ket in Freon for 5 minutes.
mately 15 inch-pounds.
1-85. INSPECTION. Inspect the parts of the vibra-
d. If replacement of the cable assembly is re-
tion transducer as follows:
quired, perform the following:
1-39
