Chapter 4. Direct Support and General Support Maintenance Instructions

TM 55-4920-325-14&P

CHAPTER

DIRECT

SUPPORT

AND

GENERAL

SUPPORT

MAINTENANCE

INSTRUCTIONS

S e c t i o n I. PREPARATION FOR MAINTENANCE, STORAGE,

AND RESHIPMENT

4-1. Preparation for Maintenance.

4-2. Preparation for Storage.

a. If test set is packed, unpack in accordance

Prepare the test set for storage in accordance

with paragraph 3-1.

with paragraph 3-3.

b. Inspect the test set in accordance with

4-3. Preparation for Reshipment.

paragraph 3-2.

Prepare the test set for reshipment in ac-

Make certain proper size fuse is installed

cordance with paragraph 3-4.

in the test set prior to operation.

Section Il. CHECKOUT AND ANALYSIS

e. Rotate Capacitance RANGE SELECTOR

4-4. Checkout Instructions.

switch (7) to X3, X10 and X50, stopping at each

The following instructions are used to de-

position. Check that CAPACITANCE INDICATOR

termine whether the test set meets minimum per-

(6) pointers do not shift from zero. If pointers shift

formance standards. Figures 4-1 through 4-8 illus-

from zero, refer to paragraph 4-23 for adjustment

trate test setup configurations and are referenced

of STRAY BAL ADJ potentiometer R120.

at appropriate points in the checkout instructions.

f. Set FUNCTION SELECTOR switch (25) to

These instructions are performed in sequence to

C A P IND HIGH CAL. CAPACITANCE lNDl-

provide complete and rapid checkout of the test

CATOR (6) shall read exact value stamped on

set,

STANDARD CAPACITOR MMF nameplate (24).

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

Refer to paragraph 2-6f for calibration if CAPAC-

to OFF and connect 115 volts, 400 Hz input power

ITANCE INDICATOR (6) reading and STANDARD

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

CAPACITOR MMF nameplate (24) value are not

paragraph 2-4c).

identical.

WARNING

g. Set FUNCTION SELECTOR switch (25) to

TEST IND PROBE SET, Capacitance RANGE SE-

Do not operate ungrounded test set.

LECTOR switch (7) to X3 and PROBE MMF range

b. Connect ground lead from test set

selector switches (28) and (29) to OFF. Release

GROUND terminal (5) to suitable ground.

PROBE 25-250 MMF control lock (26) and rotate

PROBE 25-250 MMF control (27) through entire

c. Set test set Power ON/OFF switch (2) to

range. Check that CAPACITANCE INDICATOR

ON. Check that Power ON indicator (3) lights,

(6) reads from 25 to 250 pF as PROBE 25-250

and allow five minutes for test set to warm up.

MMF control (27) is rotated from maximum coun-

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

terclockwise to maximum clockwise.

Capacitance RANGE SELECTOR switch (7) to Xl

h. Set Capacitance RANGE SELECTOR

and FUNCTION SELECTOR switch (25) to CAP

switch (7) to X1 and rotate PROBE 25-250 MMF

IND ZERO CAL. CAPACITANCE INDICATOR (6)

control (27) until CAPACITANCE INDICATOR (6)

shall read 0 pF. Refer to paragraph 2-6f for cal-

reads 30 pF and set PROBE 25-250 MMF control

ibration if CAPACITANCE INDICATOR does not

lock (26). Set PROBE MMF range selector switch

read exactly zero.

4-1