Digital Tester Functioning

TM 11-6625-2937-13

result in a variance in the tester calculated sum of the

4-3.

Digital Tester Functioning

output pin counts. This count variance can be quickly

The digital tester operates on the transition count

traced to the defective component through the use of the

concept and provides more than 700 unique logic

count readout provided on the tester. For a functional

patterns for output to the module under test. In this

description of the digital tester refer to TM 11-6625-2951-

system, each input pin of a module under test is driven

13.

by a logic pattern that differs in pulse repetition rate, duty

cycle and polarity. The program card controls the logic

4-4.

Analog Test Adapter Functioning

pattern of these stimulus signals. The module under test

is automatically exercised by up to 40 million test words

The analog test adapter is basically a breakout box that

which are applied at rates up to 4 million words per

is used at depot maintenance to gain access to module

second. These logic inputs result in an exact and

connector pins of an analog circuit card under test. It

repeatable number of logic transitions at each output pin

consists primarily of a power switch, signal generator

and at each internal node. Transition counts, which can

connectors, input power jacks, signal input switches,

be verified through fault simulator techniques provide an

power input ports and a circuit card connector. The

curate means of testing and troubleshooting a module

circuit card connector provides fan out to the 90 jacks on

under test Any fault on the digital assembly will

the panel of the analog test adapter (fig. 2-5). Controls

and monitor points are delineated in table 2-3.

4-13