TM
11-6625-2709-40
Section Il. ALIGNMENT
j. Set the BEARING selector switch on the test set
to 300.
Alignment procedures for Radio Test Set
k. Unlock potentiometer R2 located behind test set
front panel.
12. The precision bearing alignment is given in
l. Alternately adjust the AMP. BAL. control on the
resolver test set and potentiometer R2 in the test set
Alignment of the COMPASS SIMULATOR in-
to obtain the least possible signal amplitude
alignment procedures are given for the OBS in-
References to the test equipment required are given
Note: As the null is approached, increase the vertical gain of the
m. Lock potentiometer R2 shaft.
3-8. Test Equipment Required for Alignment.
n. Disconnect the equipment and replace the test
set front panel.
ment required for alignment procedures.
3-9. Precision Bearing Alignment.
3-10. COMPASS SIMULATOR Indicator Alignment.
a. Remove the
test set front panel (para 3-3a).
3a).
b. A special cable is required for precision bearing
b. Connect the test set to a 27.5-volt dc power
details of this cable.
source, and a 115-volt, 400-Hz power source.
c. Set the power switch on the control unit to PWR.
and adjust the resolver test set. (Refer to TM 11-6625-
(All other controls and switches on the control unit
and test set may be in any position.)
101.
Caution: In the fallowing steps, remove the
d. Disconnect the MOD OUTPUT connector of the
vtvm power cord from ground to eliminate the
VOR modulator from the VAR connector of the
p o s s i b i l i t y of shorting across the external power
resolver test set.
source.
e. Connect the INPUT of the vacuum tube
d. Connect the vtvm between pins C and D of con-
voltmeter (vtvm) to the VOLTMETER connector on
nector P3 of the test set pendant cable.
the resolver test set.
e. With the compass simulator control, rotate the
f. Set the function switch on the resolver test set to
COMPASS SIMULATOR indicator for a null indica-
SET ORZ.
tion on the vtvm.
g. Adjust the INPUT LEVEL control on the
Note; A 360-degree rotation of the COMPASS SIMIULATOR in-
resolver test set for a 4.25-volt indication of the vtvm.
dicator will produce two nulls on the vtvm. To determine the cor-
rect null, measure the ac voltage between pins C and G of connector
P3. This ac voltage will be less than 26 volts ac when the correct
h. Remove the INPUT of the vtvm from
null is found.
OUTPUT connector on the resolver test set.
f. With the COMPASS SIMULATOR indicator set
to the correct null, perform the following procedure to
i. Set the IND TEST switch on the test set to RCVR
zero the COMPASS SIMULATOR indicator needle.
V/L.