SELF-TEST BLOCK DIAGRAM DISCUSSION

T.O. 31W2-2GSC24-2

TM 11-5805-688-14-1

NAVELEX 0967-LP-545-3010

The card address applied as tens address signals TA1

5-578. SELF-TEST BLOCK DIAGRAM DISCUSSION.

and TA0 and units address signals UA0 through UA3 is a

number between 1 and 21 that responds to card

5-579. All of the diagnostic circuits on the cards in the

locations 1 through 21 in the MULTIPLEXER (upper)

multiplexer set are set to their error state when the SELF

card row or in the DEMULTIPLEXER (lower) card row in

TEST switch on the front panel is set to the on (up)

the multiplexer set.

position. This causes all the diagnostic error inputs to

the display card that are normally in the no-error state to

5-577. The lamp display decoder logic circuit generates

become low-level error signals during the self-test mode.

an enable signal that lights the appropriate indicator on

Therefore, the primary diagnostic circuits on the display

the front panel associated with a given error signal.

card now detect a faulty card diagnostic circuit by the

When multiplexer loss-of- timing signal MLOT- is applied

absence of an error condition on a given input. Each

to the decoder logic, the circuit generates signal LMTIM

diagnostic input to the display card in the self-test mode

to the front panel to light the LOSS OF MUX TIMING

is processed in the same priority order as that listed in

indicator.

When demultiplexer loss-of-timing signal

table 5-6.

DLOT- is applied to the decoder logic, the circuit

generates signal LDTIM that lights the LOSS OF

5-580. When a diagnostic circuit malfunction on a card

DEMUX TIMING indicator. All other error indications are

is determined, the FAULT LOCATION display on the

processed from the 3-bit address select signals applied

front panel of the multiplexer set shows a number

from the system priority encoder to the decoder logic.

between 1 and 21 and the MULTIPLEXER CARD on

The decoder logic produces signal LMCRD, LDCRD, or

DEMULTIPLEXER CARD indicator is out to identify the

LMOOT that light the MULTIPLEXER CARD,

faulty card location. When the cards have no faulty

DEMULTIPLEXER CARD, or MULTIPLEXER OUT OF

diagnostic circuits, a self-test function is performed on

TOL indicator. Each time a card failure is decoded

the primary diagnostic circuits of the display card as

(LMCRD or LDCRD), and failure signal FAIL is

described in paragraph 5-584.

generated and routed to the ERD card for use as a re-

mote alarm. Multiplexer out of tolerance signal LMOOT

5-581. After the self-test function determines that all the

is also routed to the ERD card for use as a remote

diagnostic circuits on the cards are in a no-error

alarm. When the LAMP TEST switch on the front panel

condition, the secondary self-test diagnostic circuits test

is pressed, lamp test signal LT is applied to the decoder

the primary diagnostic circuits on the display card. When

logic, which causes all the front panel indicators to light.

a diagnostic circuit on the display card is determined to

When the equipment is in the self-test mode, an indicator

be faulty during the self-test function, the FAULT

enable signal from the self-test diagnostic logic causes

LOCATION display on the front panel shows 22 and the

the decoder logic to light all the front panel indicators

MULTIPLEXER CARD indicator goes out. When the

when all the diagnostic circuits are functioning properly.

circuits on the display card are determined to be in a no-

If a diagnostic circuit associated with a given front panel

error condition, the FAULT LOCATION display on the

indicator is malfunctioning during the self-test function,

front panel shows 00 and all indicators are lighted.

the decoder logic causes the associated front panel

indicator to go out.

5-582. The MUX OFF/DEMUX OFF/NORM switch on

the display card is set to the NORM position when the

multiplexer and demultiplexer are used in the multiplexer

set.

5-157