IF DISCRIMINATOR A4200 ALINEMENT. - TM-11-5820-401-34-30465

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

TUNER A1000 ALINEMENT. (CONT)

5-18.

65-MHz Test

25.

Set R-442/VRC MC-TUNE-KC control to 65.00 MHz.

26.

Adjust AN/URM-103 RF TUNING control to 65.00 MHz. Check on frequency counter.

27.

Set AN/URM-103 LO RF UV control for zero-rf output.

28.

Note reading on ME-30(*)/U.

29.

While observing ME-30(*)W, increase rf output level of AN/URM-103 by turning LO RF UV

control until ME-30(*)/U drops to one-half of step 28 reading.

30. Adjust C1101 (14), C1201 (15), and C1301 (16) for lowest possible ME-30(*)/U reading and

minimum noise from speaker. (See test setup diagram

Mixer Adjustment

31. Set R-442/VRC MC-TUNE-KC control to 52.00 MHz.

32. Adjust AN/URM-103 RF TUNING control to 52.00 MHz. Check on frequency counter.

33. Set AN/URM-103 LO RF UV control for zero-rf output.

34. Note reading on ME-30(*)/U.

35. While observing ME-30(*)/U, increase rf output level of AN/URM-103 by turning LO RF UV

control until ME-30(*)/U drops to one-half of step 34 reading.

36. Set ME-30(*)/U to 1-volt scale.

37. Adjust C1404 (17) for lowest possible ME-30(*)/U reading. (See test setup diagram

NOTE

The ME-30(*)/U reading can also decrease if C1404 is turned in or out too far. The first

sharp decrease in the ME-30(*)/U reading will indicate the correct C1404 adjustment.

5-19. IF DISCRIMINATOR A4200 ALINEMENT.

PURPOSE. This procedure enables the discriminator to provide maximum separation of the audio

signal from the rf carrier. Adjusting for zero vdc at TP4003 ensures that T4206 and T4207 are con-

ducting equally around the carrier frequency. Adjusting for maximum ac at TP4007 ensures that the

discriminator is tuned exactly to the 11.5-MHz center frequency.

TEST EQUIPMENT AND MATERIALS

Signal Generator AN/URM-103

Matching Unit CN-901/U

Frequency Counter AN/USM-207

T-Connector UG-274/U

Power Supply PP-1104(*)/G

Loudspeaker LS-454/U

Test Cable No. 1

Voltmeter ME-30(*)/U

Multimeter ME-26(*)/U

TEST SETUP. Connect the equipment as shown in test setup diagram

R-442/VRC bottom cover. (See paragraph 2-7.)

5-101