Section II TROUBLESHOOTING - TM-11-5820-401-34-30246

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

Section II TROUBLESHOOTING

Page

Para

Subject

GeneraI. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... . . . . . . . .. . . . . .. . . . . . 4-11

4-31

Gross Troubleshooting Preliminary instructions . . . . . ......... . . . . . . . . . . . . . .4-12

....

4-33

T r o u b l e s h o o t i n g Flow Charts . . . . . . . . . . . . . ........ . . . . . .. . . . . 4 - 1 3

4-33

No Audio Troubleshooting ........... . . . . . . . . . . . . . ................ . . . . . . 4-13

4-58

A4000 Assembly Troubleshooting . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

4-68

AI000 Assembly Troubleshoot in. . . . . . . . . . . . . . . . . . . . ............... . . . . . . . . . . . . . . . .4-13

4-76

A2000, A3000 Assembly Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

4-85

Squelch Test Failure Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

Audio Power Test Failure Troubleshooting. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . 4 - 1 3

4-87

4-94

Audio Distortion Test Failure Troubleshooting . . .. . . . . . . . . . . . . . 4-13

4-101

Audio Response Test Failure (Normal Mode) Troubleshooting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-13

4-105

. . . 4-13

Audio ResponseTest Failure (Normal Mode)Troubleshooting . . . . . . . . . . . . . . . . .. . . . . . . . . . . .

4-107

SelectivityTest Failure Troubleshooting.......... . . . . . .. . . . . . . . ... . . . . . . . . . . . . . .4-13

GENERAL.

4-11.

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 responseto specific perfor-

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

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

performance degradation troubleshooting. Both kinds of troubleshooting in this section are basedon

the use of Test Set AN/GRM-114A and Maintenance Kit MK-1978/VRC.

GROSS FAILURE TROUBLESHOOTING

Gross failure troubleshooting is generated by failureof the VOLUME control test, the first of the

performance tests in section I of this chapter. Failure of the VOLUME control test indicates that no

audio at all is available at the receiver's loudspeaker jack. This implies a total failure of some module

or component resulting in complete loss of signal.Therefore, the gross troubleshooting charts are

designed to help you locate the failed module or component, with the assumption that the failed part

does not operate at all.

This assumption differs from the approach taken in performance degradation troubleshooting, which

assumes that a module or component may be responsible for slight defect symptoms because the part

may be only partially operational.

PERFORMANCE DEGRADATION TROUBLESHOOTING

When the receiver produces audio output, but the signal fails to meet certain standards, the receiver's

performance is considered degraded. Degraded performance can result in weak audio, limited

reception range, distortion, and many other problems.

4-30