RECEIVER AUDIO DISTORTION TEST. - TM-11-5820-401-34-30232

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

4-6. RECEIVER AUDIO POWER TEST. (CONT)

TEST PROCEDURE

Muted Audio Power Test

1. Connect MM-100E attenuated probe A to MK-1978/VRC SPKR jack; connect probe B to GND

jack. (See test setup diagram

2. Turn R-442/VRC VOLUME control fully clockwise.

STANDARD. MM-100E meter should indicate at least 17 volts,

3. If MM-100E meter indicates less than 17 volts, see troubleshooting chart 4-6.

Unmuted Audio Power Test

4. Change MK-1978/VRC AUDIO switch to UNMUTED setting,

5. Change MM-100E RANGE switch 10 volts.

STANDARD. MM-100E should indicate at least 7.75 volts.

6. If MM-100E meter indicates less than 7.75 volts, see troubleshooting chart 4-6.

Fixed Audio Power Test

7. Connect MM-100E attenuated probe A to MK-1978/VRC INTERCOM jack. (See test setup

diagram

8. Change MM-100 RANGE switch to 0.3 volts.

STANDARD. MM-100E should indicate at least 0.16 volts.

9. If MM-100E meter indicates less than 0.16 volts, see troubleshooting chart 4-6.

4-7. RECEIVER AUDIO DISTORTION TEST.

PURPOSE. This test checks the ability of the R-442/VRC

to minimize distortion. It is similar to the

Receiver Sensitivity Test (paragraph 4-3), except that now

a strong (20-v) rf level is used instead of

a weak (0.5-pv) one. The 20-v rf level is injected into the

R.442/VRC ANTENNA port. The audio

distortion, measured at the MUTED AUDIO output jack of

the MK-1978/VRC, should be less than 8

percent.

TEST EQUIPMENT AND MATERIALS

Power Supply PP-1104(*)/G

Test Set AN/GRM-114A

Rf Cable RG-58/U

Maintenance Kit MK-1978/VRC

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