Sectionalization

TM 11-6625-667-451 NAVAIR 16-30APM123-2/TO 33A1-367-22

5.1-6. Sectionalization Tests

meter internal battery directly across the test

leads, the comparatively high current (50 ma or

NOTE

more may damage the transistor under test. As a

See para 5.1-6.1 when using

general rule, the RX1 range of any ohmmeter

AN/TPM-25A.

should not be used when testing low-power trans-

a. General. Sectionalization tests are per

istors. Do not use an ohmmeter to check in

formed to sectionalize a fault to a module or sub-

tegrated circuits.

assembly. Two sectionalization test charts are

(3) Use of test points. Each module is

provided. The fit uses Radar Test Set

provided with test jacks to facilitate connection

AN/UPM-98A or AN/UPM-98B and the second

of test equipment. These test jacks should be

uses Radar Test Set AN/UPM-137A. Uses of the

used as directed during troubleshooting to avoid

sectionalization test charts is described in c

needless disassembly of the equipment. The test

below.

points are indicated on schematic diagrams and

b. Test Setup. A test setup is provided for

physical locations of test points are shown in

each type of test (fig. 5.1-2 and 5.1-7). In-

figure 5.1-1. Test point designator numerals for

structions for making primary power connections

each module are identified by standard RETMA

are in TM 11-6625-667-12. During the sec-

color code as shown in the chart below. Black is

tionalization tests, the required test setup is

always aground test point.

referred to and test conditions noted. Reference

should be made to figure 5.1-1 for location of

Color

Test point designator numberal

specified internal test points. Test steps must be

Brown

performed in the order given for proper equip

ment connections and conditions. General in-

Orange

Yellow

structions are provided in the charts for using the

Green

test equipment. These instructions should be

Blue

supplemented with the instruction manual ap-

Violet

plicable to the specific test equipment used.

Gray

Before proceeding with a test setup, remove the

White

(4) Use of extender card. Measurements to

unit from its case to expose test points and ad-

be made at points other than at the test jacks

justment controls as follows:

provided require the use of the extender board

(1) Unlatch and remove the test set cover.

(fig. 5.1-1). To use the extender card, the

(2) Release two screws on each side, top, and

equipment power must first be turned off. Then,

bottom of front panel with a screwdriver.

remove the circuit card that is to be tested from

(3) Lift the test set from the case.

(4) Place the unit carefully on a clean area of

its receptacle. Remove the extender card and

the workbench. Position it for convenient access

insert it in the receptacle. The module is then

inserted in the receptacle of the extender card.

to both the rear section and the front panel.

The power should then be turned on to resume

R e m o v e module retainer by removing the

testing.

securing screws.

c. Use of charts. The sectionalization test

CAUTION

charts ( d and e below) are step by step test

Be sure that no metal objects

procedures. Each step should be followed in the

(screwdrivers, pliers, etc) come in

order given for effective fault isolation. The

contact with the printed circuit board

Procedure column refers to the applicable test

while power is applied. A short circuit

setup and provides instructions for adjusting the

of the wiring could damage the solid

equipment for a measurement. The Normol in-

state circuit elements mounted on the

dication column specifies the results that should

board.

be observed. If in any step the result is not

CAUTION

n o r m a l , refer to paragraph 5.1-7 for the

Be sure that the module is properly

troubleshooting procedure necessary to localize

installed. The reversal of the module

the trouble.

could result in damage to the circuit

elements.

5.1-6

Change 5