Mode 4 Challenge Video Adjustment

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

NOTE

f. S e t t h e A N / A P M - 2 7 0 ( V ) I S L S s w i t c h t o

ON and adjust the oscilloscope to observe the

Adjust the AN/UPM-137A oscilloscope

f i r s t five pulses. Adjust Control A1R29 until the

c o n t r o l s as necessary to observe signal.

spacing between the first and fifth pulses is

Pulse width

Test point

Adjust control

8 0..5 microseconds.

( sec)

0.3 0.01

A1R8

A1TP1

0.3 0.01

5.1-14.1 Mode 4 Challenge Video Adjustment

A1TP2

A1R11

0.3 0.01

A1TP3

A1R14

Using AN/UPM-137A

A1R17

A1TP4

0.7 0.01

A2TP1

A2R2

269 2

a. P e r f o r m p r o c e d u r e s g i v e n i n p a r a g r a p h s

A2TP2

A2R7

1 2 0.1

5 . 1 - 1 3 . 1 a through g.

A1R22

A1TP5

150 7.5

b. C o n n e c t c a b l e f r o m t e s t s e t P R O B E j a c k

5.1-14. Mode 4 Challenge Video Adjustment

to AN/APM-270(V) RF IN jack.

a. Perform the procedures given in

c. Connect

AN/UPM-137A

oscilloscope

paragaphs 5.1-13 a through g.

VERTICAL-CHAN A-VIDEO IN jack to

b. Disconnect the transponder test set

AN/APM-270(V) DET VIDEO jack.

PROBE jack cable from the modulator RF

d. A d j u s t A N / U P M - 1 3 7 A o s c i l l o s c o p e

OUT connector and connect the cable to the

controls as necessary until first pulse of pulse

AN/APM-270(V) RF IN jack.

train is observed.

c. C o n n e c t t h e o s c i l l o s c o p e C H A N N E L A

e. A d j u s t c o n t r o l A 1 R 3 2 u n t i l p u l s e w i d t h i s

cable to the AN/APM-270(V) DET VIDEO

0 . 5 0.2 5sec.

jack.

d. A d j u s t t h e o s c i l l o s c o p e s w e e p a n d d e l a y

f. S e t t e s t s e t I S L S s w i t c h t o O N a n d a d j u s t

c o n t r o l s until the first pulse of the pulse train is

A N / U P M - 1 3 7 A oscilloscope to observe first five

observed.

pulses. Adjust control A1R9 until spacing

e. Adjust control A1R32 until the pulse width

between first and fifth.pulses is 8 0.15 sec.

is 0.5 0.1 microsecond.

Section IV. GENERAL SUPPORT TESTING PROCEDURES

NOTE

See Section VI When Using

A N/ T P M-

2 5A

5.1-15. General

there is a problem in the 5-volt power

supply (Module A3).

These procedures describe tests for the trans-

5.1-16. Mode 4 Reply Decoder Tests

ponder test set mode 4 operation. They should

a. Test Equipment Required.

be performed after repair of module A1, A2, or

(1) Oscilloscope AN/USM-281A.

A3. Two test procedure are provided for both

(2) Modulator MD-796.

the Mode 4 Reply Decoder Tests and the Mode

(3) Test Facilities Set, Transponder Test

4 Challenge Video Tests. The first procedure

Set AN/APM-270(V).

uses conventional test equipment and the Radar

(4) Generator, Signal AN/URM-64A.

Test Set AN/UPM-98A or AN/UPM-98B. In

(5) Wattmeter AN/URM-98.

the second test procedure and Radar Test Set

b. Test Connections and Conditions.

AN/UPM-137A

the

only

piece

test

( 1 ) Apply power to the test equipment and

equipment used.

permit a 15-minute warmup period.

CAUTION

(2) Connect the equipment as shown in

When using the test set in Mode 4, if

f i g u r e 5.1-7, except connect the rf power test set.

the REJECT light does not come on

cable (through rf bolometer) to the modulator

momentarily before the ACCEPT light,

RF OUT connector.

5.1-22 Change 5