1-57
The angles shown in these tables do not apply to systems using differentials, or to systems whose units
are incorrectly zeroed.
Table 1-2.—General Symptoms
Preliminary Actions: Be sure TR is not jammed physically. Turn TX slowly in one direction and
observe TR.
SYMPTOMS
TROUBLE
Overload Indicator lights Units hum at all TX settings One
unit overheats TR follows smoothly but reads wrong
Rotor circuit open or shorted. See
table 1-3.
Overload Indicator lights Units hum at all except two
opposite TX settings Both units overheat TR stays on one
reading half the time, then swings abruptly to the opposite
one. TR may oscillate or spin.
Stator circuit shorted. See table 1-4.
Overload Indicator lights Units hum on two opposite TX
settings Both units get warm TR turns smoothly on one
direction, then reverses
Stator circuit open. See table 1-5.
TR reads wrong or turns backward, follows TX smoothly
Unit interconnections wrong. Unit
not zeroed. See tables 1-6 and 1-7.
Table 1-3.—Open or Shorted Rotor
Preliminary Action: Set TX to 0° and turn rotor smoothly counterclockwise.
SYMPTOMS
TROUBLE
TR turns counterclockwise from 0º in a jerky or erratic
manner, and gets hot.
TX rotor open
TR turns counterclockwise from 0º or 180º in a jerky or
erratic manner. TX gets hot.
TR rotor open
TR turns counterclockwise from 90º or 270º, torque is about
normal, motor gets hot, and TX fuses blow.
TX rotor shorted
TR turns counterclockwise from 90° or 270°, torque is about
normal, TX gets hot, and TR fuses blow.
TR rotor shorted
