TM 55-4920-429-13
(4) Remove the jumper wire.
l
l
NOTE
When a test includes a requirement that an ac voltage be in-phase
or out-of-phase, oscilloscope channel A must be connected across
the digital multimeter. Oscilloscope channel B must be connected
to the ac source and the oscilloscope externally triggered from the
ac source.
The minus sign (-) before an ac voltage indicates out-of-phase.
(5) Connect a variable ac power supply to receptacle pins J1-s and J1-t. Voltage shall be 180° out
of phase with respect to the 115 volt ac source at J l-B.
(a) Set ROLL switch to MAX EXT.
(b) Adjust the power supply for .0000 on the dmm.
(c) Connect an external digital multimeter, set to measure ac volts, to the output of the ac power
supply. The voltage shall be 1.113 to 1.417 volts ac.
(6) Connect a variable ac power supply receptacle pins J1-s and J1-t. Applied voltage shall be in
phase with respect to the 115 volt ac source at J1-B.
(a) Set the ROLL switch to MAX RETR.
(b) Adjust the power supply for .0000 on the dmm.
(c) Connect an external digital multimeter, set to measure ac volts, to the output of the ac power
supply. The voltage shall be 1.113 to 1.417 volt ac.
(7) Disconnect external voltage source and decade resistor.
i. Test the yaw servo loop as follows: (See fig. 4-2.)
(1) Connect a decade resistor, set to 2,000 ohms, across receptacle pins J1-HH and J1-v.
(2) Set the MONITOR SELECT switch to YAW.
(3) Connect a jumper across pins J1-FF and J1-GG. For each combination of switch settings, the
dmm shall read as listed below.
MONITOR SELECT
DMM
YAW SWITCH
DRIVE/FDBK
READING
0
SELF FDBK
+0.500 To +0.500
MAX EXT
HI DRIVE
+12.0 To +14.0
85% EXT
HI DRIVE
+8.34 To+ 10.62
85% EXT
RTN DRIVE
+0.480 To +0.600
0
HI DRIVE
-0.500 To +0.500
85% RETR
HI DRIVE
-8.34 To -10.62
85% RETR
RTN DRIVE
-0.480 To -0.600
MAX RETR
HI DRIVE
-12.0 To -14.0
4-19
