TM 55-4920-429-13
(4) Remove the jumper wire.
NOTE
l
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-W and J1-X. Voltage shall be 180°
out of phase with respect to the 115-volt ac source at J1-B.
(a) Set the PITCH 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 0.8602 to 1.0940 vat.
(6) Connect a variable ac power supply to receptacle pinJ1-W and J1-X. Voltage must be in
phase with respect to the 115 volt ac source at J1-B.
(a) Set the PITCH 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 0.8602 to 1.0940 vat.
(7) Disconnect the external power supply and decade resistor.
h. Test the roll servo loop as follows: (See fig. 4-2.)
(1) Connect a decade resistor, set to 2,000 ohms, across receptacle pins J1-NN and J1-MM.
(2) Set the MONITOR SELECT switch to ROLL.
(3) Connect a jumper across pins J1-s and J1-t. For each combination of switch settings, the dmm
shall read as listed below.
MONITOR SELECT
DMM
ROLL SWITCH
DRIVE/FDBK
READING
0
SELF FDBK
-0.500 To +0.500
MAX EXT
HI DRIVE
+8.00 To +14.00
85% EXT
HI DRIVE
+5.41 To +6.89
85% EXT
RTN DRIVE
+0.308 To +0.392
0
HI DRIVE
-0.500 To +0.500
85% RETR
85% RETR
MAX RETR
HI DRIVE
RTN DRIVE
HI DRIVE
-5.41 To -6.89
-0.308 To -0.392
-8.00 To -14.00
4-18
