TM 55-4920-429-13
4-32. ILCA DRIVE. These tests insure that valve command, SUM 1/SUM 2, and feedback circuits for
pitch, roll, and yaw ILCA function as required. (See FO-8 for connector pin patterns.)
a. Connect the digital multimeter, set to read dc volts, across pins J3-A(+) and J l-C. Set the HYDR
VALVE switch to OPEN. The digital multimeter shall read +23 to +29 volts.
b. Set the HYDR VALVE switch to CLOSE. The digital multimeter shall read -1 to +1 volt.
c. Disconnect the digital multimeter.
d. Set the METER SOURCE switch to ILCA DRIVE.
e. Connect a variable ac power supply to the receptacle pins listed below. Connect a digital mul-
timeter, set to measure ac volts, across the output of the power supply. Adjust the power supply to 10 “
volts. The dmm shall read +9.65 to +10.35 for each test connection and position of the MONITOR
SELECT switch.
AC SUPPLY
MONITOR
SELECT
LINE
NEUTRAL
PITCH/ROLL/YAW
FDBK
J1-N
J1-M
PITCH
SUM 2
J1-L
J1-M
PITCH
SUM 1
J1-m
J1-k
ROLL
SUM 2
J1-j
J1-k
ROLL
SUM 1
J1-LL
J1-KK
YAW
SUM 2
J1-BB
J1-KK
YAW
SUM 1
f. Disconnect the ac power supply and digital multimeter.
g. Test the pitch servo loop as follows: (See fig. 4-2.)
(1) Connect a decade resistor, set to 2,000 ohms, across pins J1-JJ and J1-PP.
(2) Set the MONITOR SELECT switch to PITCH.
(3) Connect a jumper across pins J1-W and J1-X. For each combination of switch settings, the
dmm shall read as listed below.
ILCA DRIVE
MONITOR SELECT
DMM
PITCH SWITCH
DRIVE/FDBK
READING
0
SELF FDBK
-0.500 To +0.500
MAX EXT
HI DRIVE
+6.00 To +14.00
85% EXT
HI DRIVE
+4.162 To +5.297
85% EXT
0
85% RETR
RTN DRIVE
HI DRIVE
HI DRIVE
+0.237 To +0.302
-0.500 To +0.500
-4.162 To -5.297
85% RETR
RTN DRIVE
-0.237 To -0.302
MAX RETR
HI DRIVE
-6.00 To -14.00
4-16
