Mode 4 Module A1 Troubleshooting

TM 11-6625-667-45

e. Mode 4 M o d u l e A 1 T r o u b l e s h o o t i n g .

NOTE

Refer to figure 5.1-3 for socket voltages and resistances and figure 5.1-8 for wave-

forms.

Trouble symptom

Probable trouble

Corrective measures

a. Adjustment.

a. Refer to procedure in paragraph

Receiver sensitivity ab-

normal; not within -9

5.1-13.

b. Transistor A1Q6.

b. Check socket resistances.

0.5 dbm.

Check waveform at test point

M14 challenge shaper A1SS6

Challenge video pulses

A1TP6. If normal, check socket

(36) not present.

(AlM11) or transistor

A1Q4.

resistances of A1Q4. If ab-

normal, check socket waveforms

of A1M11.

a. Refer to procedure in paragraph

a. Adjustment.

Challenge video pulse width

5.1-14.

abnormal.

b. Check integrated socket wave-

b. M4 challenge shaper A1SS6

forms at A1M1l.

(A1M1l).

Transistor, A1Q6 or M4 challenge

Check socket wavafonns.

Challenge video pulse

shaper A1SS6.

spacing abnormal.

Integrated circuit A1M8B or

Check socket waveforms.

ISLS pulse missing;

pulse train nomnal.

A1M9, or transistor A1Q3.

a. Adjustment.

a. Adjust control A1R28.

ISLS pulse spacing

b. Check socket waveforms.

b. Transistor A1Q3.

abnormal.

c. Refer to procedure in paragraph

Second reply pulse decode a . Adjustment.

5.1-14.

spacing abnormal.

b. Second decode pulse shaper

b. Check socket waveforms.

A1SS2 (A1M3).

a. Adjustment

a. Refer to pmxedum in pamgraph

Third reply pulse decode

5.1-14.

spacing abnormal.

b. Third decode pulse shaper

b. Check socket waveforms.

AlSS1 (A1M2).

f . Mode 4 Module A2 Troubleshooting.

NOTE

Refer to figure 5.1-4 for socket voltages and resistances and figure 5.1-9 for wave-

forms.

Item

Trouble symptom

Probable trouble

No.

Corrective measures

a. Counter A2FF1 to A2FF7

a. Check socket waveforms.

Reply reject count is

improper for direct and

(A1M1 to A1M6).

b. Time-decoded video delay

b. Check wavefomns at test points

radiation operation.

at A2TP1 and A2TP2

A2SS1 (A2Q1/Q2) or time-

respectively. If abnormal,

decoded video delay A2SS2

perform adjustment in para-

(A2M17).

graph 5.1-13. If still ab-

normal, check socket wave-

forms.

Reply reject count is

Decode video sensing gate

improper for direct

A2M14A, video sensor enablle

Check socket waveforms.

operation only.

A2FF15 (M14C), 16-count reset

gate A2M15A or A2M15B,

or gate A2M18B.

Same as 2 above

Double-reply reject in-

Same as 2 above.

operative; 16-count opera-

tion normal.

Counter reset abnormal.

PRF counter A2FF8 to A2FF14

Check socket waveforms

(A2M17 to A2M8) or gates

A2M16A and B.

5.1-13

Change 1