TM 11-6625-2398-15-3
Step
Test equipment
Equipment under
Test
Performance
No.
control settings
test control settings
procedure
standard
Test lead to:
VIDEO switch
position
CHAL MON
ENABLE J4
P1-H
SUM XTAL
CUR J5
P1-B
ISLS INHIBIT J6
P1-L
DIFF XTAL CUR
RT FAULT J2
P1-G
LVPS MON J3
P1-E
CHAL MON
ENABLE J4
SUM XTAL
CUR J5
P1-B
J7
P1-A
d. Video switch to
d. Successively connect one multi-
d. Meter must indicate
positions indicated in
meter test lead to the active pins on
an open circuit for each
test procedure.
plug P1 (figure 6-20). Successively
test, except for the
connect the other multimeter lead
switch positions and
to J1 (rotating VIDEO switch S1
jacks requiring continuity
through all nine positions) and J2
to plug P1 in a, b and c
through J8 for each active pin.
above.
8-5. Insulation Resistance Tests on Cables
(1) When possible, connect the two test leads
to opposite ends of the cables to avoid shorting.
21A/U.
(2) To connect a test lead to a male pin of a
cable connector, adapt the alligator clip by connecting it
b. Test Connections Conditions.
Connect the
to a female pin of the correct size.
equipment as shown in figure 8-2 in accordance with the
directions in the steps of the procedure below. To
(3) To connect a test lead to a female pin of a
accomplish connection of the test leads from the LINE
cable connector, adapt the alligator clip by connecting it
and GROUND terminals of Ohmmeter ZM-21A/U to the
to a male pin of the correct size, or to a solid wire of the
pin contacts of the cable connectors, proceed as follows
correct size.
whenever applicable:
Step
Test equipment
Equipment under
Test
Performance
No.
control settings
test control settings
procedure
standard
1
ZM-21A/U
None
Warning:
Test leads of Ohmmeter ZM-21A/U are at potentials up to 500 volts when the ohmmeter hand crank is being rotated.
To avoid injury make all connections when the hand crank is not being rotated. DO NOT handle the test leads while
the crank is rotating.
Check insulation resistance of coaxial
cables W13, W14/W15(2), W16.
W21, W45 and W47 as follows:
a. Connect the LINE terminal of the
ohmmeter to the center contact of one
plug.
b. Connect the GROUND terminal of
the ohmmeter to the shell of a plug.
c. Wrap an uninsulated wire around
the outer covering of the cable and
connect the wire to the GUARD
terminal of the ohmmeter.
d. Rotate the hand crank of the
Meter reading of 100
ohmmeter at 160 (minimum) revolu-
megohms or higher
tions per minute (rpm) and read the
must be obtained.
insulation resistance on the meter.
2
Observe Warning in step 1 above.
Check insulation resistance of power
cable W32 (fig. 6-10) as follows:
a. Connect the LINE and GROUND
8-5
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