TM 11-6110-211-15
c. Troubleshooting Chart--Continued
Probable cause
Corrective action
Symptom
Check dc resistances of power transformer
Shorted winding in power
No 26-volt ac at fixed field of motor of
T202 (para. 3-7). Replace defective
navigation indicator motor-generator.
transformer T202.
power transformer. Check and, if neces-
Shorted or open
(No output at terminal 11 of connector
sary, replace defective capacitor.
capacitor C204.
P201.)
lator TS-382/U, or equivalent) is required. The
3-6. Voltage and Resistance Measurements
signal source should be capable of supplying both
The voltages and resistances at the contacts of
in-phase and 180 out-of-phase signals, with re-
each transistor are shown in figures 3-1 and 3-2.
spect to the 115-volt ac supply, and should be iso-
lated from power ground for reversing purposes.
is connected in the circuit; figure 3-2 shows values
b. Test Requirements.
for the circuit when the transistor is removed from
(1) If a pilot's navigation indicator is un-
the circuit. Voltage measurements shown in fig-
available, the dummy loads listed in the
ures 3-1 and 3-2 are for AM-3209/ASN with a 0.1-
following chart may be substituted.
volt, 400-cps input applied to terminals 5 and 6
of connector P201 and 115 ac applied to terminals
Dc resistance
Connect between
7 and 12 of connector P201.
Replaces
(ohms) of
servoamplifier
dummy
(millihenrys)
pins
3-7. Additional Troubleshooting Data
The following chart lists the normal dc resist-
Fixed field of
135
31
11 and 12 . . .
motor.
ances of the transformer windings in the AM-
90
37
Control field of
13 and 12 . . .
3209/ASN
motor.
14 and 12 .
..
90
37
Control field of
Dc resistance
Transformer
Measure between wires
motor.
(ohms)
Generator field of
190
71
8 and 12 . . .
excitation.
Brn and orn . . . . . . . . 2, 500+ 500
T201 . . . . . .
500 75
Grn/pr and blk/brn . . . . . .
(2) Connect a jumper wire between terminals
500 75
Blk/orn and brn/orn . . . . . . ..
12024
Yel and grn _______________
A and J of the test terminal board (zero
12024
Grn and blu ______________
input signal). Voltages at the terminals
Brn/yel and brn/grn . . . . . . . . . .
304. 5
should be as indicated in the following
304. 5
Brn/grn and brn/blu . . . . . . . . .
chart:
489. 6
T202 . . . . . . Yel and orn . . . . . . . . . . . .
Orn and brn . . . . . . . . . . .
8. 53.4
156
Brn and grn . . . . . . . . . . . . .
Measure
between
terminals
indication
(volts ac)
3-8. Testing
D and I . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . .
0 to 0.9
E and I . . . . . . . . . . . . . . . . . . . . . . . .
0 to 0.9
G and I . . . . . . . . . . . . . . . . . . . . . . . . . . . .
19 to 31
Procedures for testing the AM-3209/ASN are
F and I . . . . . . . . . . . . . . . . . . . . . . . . . . .
19 to 31
given below. The test setup required to test the
amplifier is shown in figure 3-3.
(3) Remove the jumper wire between termi-
a. Signal Requirements. A variable 0- to 1-volt,
400-cps, single-phase signal source (Audio Oscil-
nals A and J.
3-3
