Section II TROUBLESHOOTING - TM-11-5820-401-34-30119

TM 11-5820-401-34-3/0967-LP-432-3060

RECEIVER SELECTIVITY TEST. (CONT)

3-10.

31. Turn AN/URM-103 LO RF UV control clockwise until display appears on AN/USM-207. Note

frequency displayed.

32. Adjust AN/URM-103 RF TUNING control for 29.59-MHz display on AN/USM-207.

33. Disconnect T-connector from AN/USM-207.

34. Reset AN/URM-103 LO RF UV control to level arrived at in step 23.

STANDARD. R-442/VRC CALL lamp should be off.

35.

If R-442/VRC CALL lamp is lit, see troubleshooting chart 3-6.

36.

Turn AN/URM-103 RF TUNING control slowly clockwise until R-442/VRC CALL lamp lights.

37.

Reattach T-connector to AN/USM-207.

38.

Turn AN/URM-103 LO RF UV control clockwise until display appears on AN/USM-207. Note

frequency displayed.

39. Subtract frequency noted in step 38 from frequency noted in step 31.

STANDARD. The difference between the two frequencies should be 80 kHz or less.

40. If difference between frequencies noted in steps 31 and 38 is more than 80 kHz, see

troubleshooting chart 3-6.

Section II TROUBLESHOOTING

Page

Para

Subject

3-33

General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 3-11

3-34

Gross Troubleshooting Preliminary lnstructions... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-12

3-36

Troubleshooting Flow Charts......... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-36

3-13

No Audio Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

3-54

SINAD Test Failure Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-61

Squelch Test Failure Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-63

Audio Distortion Test Failure Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

Audio Response Test Failure

Troubleshooting (Normal Mode) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-64

Selectivity Test Failure Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-65

A1000 Assembly Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-66

3-71

3-13

A2000, A3000 Assemblies Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

A4000 Assembly Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-77

A5000 Assembly Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-13

3-80

GENERAL.

3-11.

This section contains troubleshooting charts which will help you diagnose failures in the R-442/VRC

receiver. The troubleshooting charts are designed to isolate faults in response to specific

performance problems noted during performance testing in section I of this chapter.

There are two basic kinds of troubleshooting charts provided: gross failure troubleshooting and

performance degradation troubleshooting. Both kinds of troubleshooting are based on the use of

TMDE and Maintenance Kit MK-1978/VRC.

3-33