o.
Frequency Adjust Rheostat (Precise Sets Only).
ARMY TM 9-6115-464-12
AIR FORCE TO 35C2-3-445-1
NAVY NAVFAC P-8-624-12
(1) Removal.
(a) Tag and disconnect electrical leads to frequency adjust rheostat.
(b) Loosen setscrew in control knob (62, Figure 4-38, sheet 2 of 3), then remove knob from rheostat
shaft.
(c) Remove nut (63), washer (64) and keyed washer (66) to remove rheostat (65) from panel.
(2) Cleaning and Inspection.
(a) Clean rheostat with filtered compressed air and a soft bristle brush or wipe with a clean, lint-free
cloth lightly moistened with an approved solvent.
(b) Visually inspect rheostat for cracked casing, corrosion, stripped or other wise damaged threads,
and evidence of shorting or other damage.
(3) Testing.
(a)
(b)
(c)
(d)
(e)
Connect an ohmmeter across outer terminals of rheostat. Ohmmeter should indicate 500 ohms
resistance.
Rotate rheostat shaft counterclockwise as far as it will go.
Connect ohmmeter between center terminal and either outer terminal. Ohmmeter should indicate
0 ohms resistance.
Slowly, at an even rate, rotate the rheostat shaft clockwise as far as it will go. Ohmmeter should in-
crease at an even rate from 0 to 500 ohms.
If ohmmeter indication changes erratically or is not 500 ohms when the rotation is completed,
the rheostat is defective and shall be replaced.
(4) Installation.
(a) Install rheostat (65, Figure 4-38, sheet 2 of 3) on panel and secure with keyed washer (66),
washer (64), and nut (63).
(b) Install control knob (62) on rheostat shaft and secure with setscrew.
(c) Connect electrical leads to frequency adjust rheostat.
p.
Voltage Adjust Rheostat.
(1) Removal.
(a)
(b)
(c)
Tag and disconnect electrical leads to voltage adjust rheostat.
Loosen setscrew in control knob (67, Figure 4-38, sheet 2 of 3) and remove knob from rheostat
shaft.
Remove nut (68) to remove rheostat (69).
(2) Cleaning and Inspection.
(a) Clean voltage adjust rheostat with filtered compressed air and a soft bristle brush or wipe with
a clean, lint-free cloth lightly moistened with an approved solvent.
(b) visually inspect rheostat for cracked casing, corrosion, stripped or othetwise damaged threads,
and evidence of shorting or other damage.
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