Localizing Troubles-CONT. - TM-11-6625-667-450063

TM 11-6625-667-45/NAVSHIPS 0969-249-8010/NAVAIR 16-30APM123-2/TO 33A1-3-367-22

Probable trouble

Corrective measures

Symptom

a. Check waveform at A10TP4. If normal,

P1 and P3 pulses are not forming or

No pulse are present at test

encode enable IFF1 inoperative.

proceed with e below. If abnormal,

point A16TP1 (ISLS switch

proceed with b below.

ON or OFF) for all MODE

b. Check waveform at A4TP5. If normal,

switch positions.

proceed with c below. If abnormal,

check resistances at A5Q14 and A5Q15.

c. Check waveform at A4TP1. If normal,

proceed with d below. If abnormal,

check socket resistances at transistors

A4Q1 and A4Q2.

d. Check waveform at A4TP2. If normal,

proceed with e below. If abnormal,

oheck resistances at A4Q3 and A4Q4.

e. Replace delay-line module A6DL1.

Gate diode A5CR3---------------- Check diode A5CR3.

P1 pulse rnissing, but P2 and P3

pulses are present at test

point A16TP1.

a. P1 gate-------------------------

a. Check waveform at test point A5TP2.

During all modes, P1 and P2

If normal, check resistances at transis-

pulses are not present at test

point A16TP1, but P3 pulse is

tor A5Q12. If abnormal, proceed with

b below.

present.

b. MODE switch -------------------- b. Check resistance at transistor A5Q11. If

normal, check continuity of MODE

switch A15S5, section F.

a. P1 emitter follower-----

Check resistances of P1 emitter follower

During one mode,Pl and P2

b. MODE switch contacts.

associated with inoperative mode (mode

pulses are not present at test

point A16TP1 but P3 pulse is

1: A5Ql; mode 2: A5Q2; mode 3: A5Q3;

mode C: A5Q4; or test: A5Q5).

present.

a. P3 gate-------------------------

a. Check waveform at test point A5TP4.

P3 pulse not present at test

If abnormal proceed with b below. If

point A16TP1.

normal, proceed with c below.

b. Gate diode A5CR2---------------- b. Check resistances at transistors A5Q6 and

A5Q7.

c. P 3 emitter follower---------- c. Check resistance at transistor A5Q8. If

normal, replace gate diode A5CR2.

check waveform at A4TP3. If normal,

Encode line driver ISS1 or SLS de-

only P2 pulse is missing with

lay generator 1SS3.

ISLS switch a t ON and OFF

check resistances at transistors A4Q7 and

A4QS. If abnormal, check resistances at

at test point Al6TP1.

A5Q4 and A5Q5.

P2 modulator driver or diode ACR57- - Check resistances at transistors A5Q17 and

P2 pulse missing at test point

A16TP1 With ISLS switch at

A5Q18; if resistances are normal, check

at OFF, but is present when

A5CR7.

it is at ON.

Diode

A4CRl5----------------------Check

diode.

P2 pulse missing at test point

A16TP1 with ISLS switch at

ON, but is present when it is

at OFF.

Encoder enable IFF1 locked in

D E p u l s e m i s s i n g - - - - -Check waveform at A5TP3. If abnormal,

set state, P3 pulse present at

check resistances at A5Q9 and A5QI0. If

test point A16TP1.

normal, check resistances at transistors

A4Q3 and A4Q5.

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