5.925 MHz Oscillator Detector Output Amplitude Adjustment

TM 11-6625-467-34

b. Using the module extender board, extend

c. Pull the shaft of interlock switch S12 to the

3.975-/5.925-MHz oscillator circuit card HV4 above

override position.

the card cage.

d. S e t t h e P O W E R S E L E C T O R s w i t c h t o

c. Connect power to the equipment and set the

NORMAL.

POWER switch to ON.

e . Set the CIRCUIT SELECTOR switches to

d. Pull the shaft of interlock switch S12 to the

6103.

override position.

f. Connect the vhf signal generator to J12 (coax-

e. S e t t h e P O W E R S E L E C T O R s w i t c h t o

ial connector near transmit audio module plug-in,

NORMAL,

figure 3-2) and set the output level to 100 millivolts.

f. Set the CIRCUIT SELECTOR switches to

g. Push the PRESS TO TEST button and adjust

0189.

the AN/GRM-50 frequency control (approximately

g. Connect the AN/URM-145 (RF voltmeter) to

5 0 0 kHz) for a peak reading on the TEST METER.

the 3 MC jack on the front panel of the test set and

NOTE

adjust the LOW FREQ AMPL control for 29 milli-

Obtain a convenient on-scale TEST

volts on the AN/URM-145.

METER reading by adjusting the 500 KC

h. Push the PRESS TO TEST button and adjust

FILTER control on the front panel of the

R9 on the circuit card for a reading of 100 percent on

test set.

the TEST METER.

i. Remove the module extender board, and re-

h. Set the CIRCUIT SELECTOR switches to

place the 3.975-/5.925-MHz oscillator card in the

2003.

card cage.

i. Push the PRESS TO TEST button and set the

500 KC FILTER control for a reading of 47 percent

3-27. 5.925 MHz Oscillator Detector Output

on the TEST METER reading.

Amplitude Adjustment

j. Set the CIRCUIT SELECTOR switches to

Perform the following procedures to adjust the

2103.

k. Push the PRESS TO TEST button and adjust

5.925-MHz oscillator detector output amplitude:

a. Remove the test set from the case.

trimmer capacitors C9 and C10 on the load/500-kHz

b. Using the module extender card, extend

filter circuit card HV7 for a peak reading on the

3.975-/5.925-MHz oscillator circuit card HV4 above

TEST METER.

l. Push the PRESS TO TEST button and adjust

the card cage.

c. Connect power to the equipment and set the

R32 (use access hole in the front panel, figure 3-2)

for a reading of 80 percent on the TEST METER.

POWER switch to ON.

d. Pull the shaft of interlock switch S12 to the

m. Disconnect the vhf signal generator from J12.

override position.

3-29. 500-kHz Discriminator Adjustment

e. S e t t h e P O W E R S E L E C T O R s w i t c h t o

(fig. 3-29)

NORMAL.

T h e procedure f o r adjusting the discriminator

f. Set the CIRCUIT SELECTOR switches to

0299.

center frequency is presented in a below. The pro-

g. Connect the AN/URM-145 to the 5 MC jack on

cedure for adjusting the discriminator output level

the front panel of the test set and adjust the LOW

is presented in b below. Perform the two procedures

FREQ AMPL control for 29 millivolts on the AN/

in sequence. Before performing the procedures, in-

URM-145.

sure that the 500-kHz fm oscillator frequency is ad-

h. Push the PRESS TO TEST button and adjust

justed properly (para 3-24):

a. Distriminator Center Frequency Adjustment.

R20 on the circuit card for a reading of 100 percent

on the TEST METER.

(1) Remove the test set from the case.

i. Remove the module extender board and re-

(2) Using the module extender board, extend

place the 3.975-5.925-MHz oscillator circuit in the

the audio amplifier/detector circuit card HU7 above

card cage.

the card cage.

(3) Connect the equipment as shown in figure

3-29. (Do not connect wires shown by dashed lines.)

3-28. 500-kHz Bandpass Filter Adjustment

(4) Connect power to the equipment and set

the POWER switch to ON.

Perform the following procedures to adjust the 500-

kHz bandpass filter:

( 5 ) Set the POWER SELECTOR switch to

NORMAL.

a. Remove the test set from the case.

( 6 ) Set the CIRCUIT SELECTOR switches to

b. Connect power to the equipment and set the

3215.

POWER switch to ON.

3-46