Alignment. - TM-55-4920-325-14-P0071

TM 55-4920-325-14&P

u. Place the following cables and accessories

WARNING

into the storage compartment of transit case as-

Do not operate ungrounded test set.

sembly (52):

b. Connect ground lead to test set GROUND

(1) Main cable assembly.

terminal (5) and to suitable ground.

(2) Twelve (12) adapter cable assembies.

Set Power ON/OFF switch (2) to ON and

check that Power ON indicator lights; allow five

(3) Seven BNC connector assemblies.

minutes for test set to warm up.

(4) Ground lead assembly.

d. Set CAP-RES CHECK switch (13) to CAP,

and FUNCTION SELECTOR switch (25) to CAP

(5) Test lead assembly.

IND ZERO CAL.

(6) Indicator test cable.

Rotate Capacitance RANGE SELECTOR

(7) Two break-in cables.

switch (7) through X1, X3, X10 and X50, stopping

at each position. Use an insulated screwdriver to

(8) Five tee connectors.

adjust potentiometer R120 (16, figure 4-13) slowly

v. Perform complete checkout procedure

while switching back and forth through all four

(see paragraph 4-4) to verify operation of the test

positions.

set.

f. Lock potentiometer R120 in that position

w. Close lid of transit case assembly (52) and

which produces a minimum shift of CAPAC-

secure two snap locks.

ITANCE INDICATOR (6, figure 2-1) subdial point-

er, without regard to actual reading.

4-23. Alignment.

g. If subdial pointer of CAPACITANCE lNDl-

The following procedure is used to align

CATOR (6) is off zero when minimum shift is

STRAY BAL ADJ potentiometer R120 to minimize

achieved, adjust Capacitance ZERO ADJUST con-

the effect of stray capacitance on capacitance in-

trol (9) (see paragraph 2-8f.

dicator readings.

a. Set Power ON/OFF switch (2, figure 2-1)

to OFF and connect 115 volts, 400 Hz input power

to test set 115V 400 CPS connector (4).

4-27