DETAILED CIRCUIT DISCUSSION - TM-11-5805-688-14-10249

T.O. 31W2-2GSC24-2

TM 11-5805-688-14-1

NAVELEX 0967-LP-545-3010

The sixth remote alarm relay (K6) is normally held open

The minor frame counts generated in the diagnostic

in an energized condition and provides a closed-loop

circuits are applied to a diagnostic comparator that also

condition when the power supply is shut down. The six

has the functional minor frame counts being applied.

remote alarm relays and their associated outputs are

When the circuits are in a no-error condition, the minor

listed below with associated functional descriptions.

frame counts should compare and produce an A=B

output from the comparator to the diagnostic flip-flop

Relay

circuit. The A=B output from the diagnostic comparator

Signal Output

Cause

No.

occurs at the time that end-of-scan signal DEOS2B- is

K1i

FAILC1/FAILC2

Card failure

applied to the diagnostic flip-flop. Therefore, each A=B

(FAIL) diagnostic

condition causes a high (no error) signal from the flip-

signal from display

flop. When an error is present and the A=B signal is not

card

generated, a low is applied to the K input of the flip-flop,

causing loss of minor frame error signal LOMFC- to be

OOTC1/OOTC2

Out-of-tolerance

generated.

(LMOOT)

diagnostic signal

from display card

5-550. DETAILED CIRCUIT DISCUSSION.

LERRC1/LERRC2

Link error rate

signal for link error

rate circuits on

5-551. Minor Frame Generation Circuits. Overhead

ERD card

data pulses DOD- are clocked into overhead shift

data bits from U35 are applied to the B inputs of minor

LOFBC1/LOFBC2

Demultiplexer loss-

frame comparator U37. The fifth bit input to pin 3 of U37

of-frame B (DLOF)

is on-line signal DOD- from inverter U44-6. When the

signal from FS

equipment is initially turned on, minor frame counter

card (a latched

U21, U36 produces a 5-bit minor frame count that is

condition)-

applied to the A inputs of U37. At this time, the two sets

of minor frame counts applied to U37 do not compare.

LOFAC1/LOFAC2

Loss of frame A

The output from U37 is an inhibit to AND gate U27-8 and

sync (DFS) signal

an enable to AND gate U27-6. Therefore, a given series

from FS card

of signals DEOS2B- and word count DW28 cause the

outputs from AND gate U27-6 to decrement up/down

PSFC1/PSFC2

Power supply fail

counter U20 until count zero is produced. Count zero is

(PSFR) error

applied to preset flip-flop U21-6. When U21-6 is preset,

signal from power

U21-7 goes low and presets counter U36. At this time,

supply

during word 28, the minor frame count in U35 is preset

into U36. This action synchronizes the minor frame

5-549. Diagnostic Circuits. The minor frame generation

count output from U36 to the minor frame count output

circuits that produce the minor frame counts are

from U35.

duplicated by the diagnostic circuits shown in figure 5-42.

Change 1 5-148