Temperature Compensated Oscillator Frequency Adjustment

TM 11-5820-509-35

KILOCYCLES indicator to 7000 and set the rotary switch

switch on the antenna simulator to the 11.0 MHz

on the antenna simulator to the 7.0 MHz position.

position.

(11) Adjust A3L72 (fig. 3-96) for maximum rf

(19) Adjust A3L76 (fig. 3-105) for maximum rf

grid drive as indicated by the multimeter connected to

test point J104.

teat point J104.

(12) Repeat

step

(2)

except

set

c. Power Amplifier Bias Adjustments.

KILOCYCLES indicator to 8000 and set the rotary switch

NOTE

on the antenna simulator to the 8.0 MHz position.

Perform these adjustments only after

(13) Adjust A3L73 (fig. 3-96) for maximum rf

completing

the

alignment

grid cave as indicated by the multimeter connected to

procedures of step b above.

teat point J104.

(1) Connect the dc probe of the multimeter to

(14) Repeat

step

(2)

except

set

the following test jacks on Power Supply PP.

KILOCYCLES indicator to 9000 and set the rotary switch

3518/PRC-47 (A8A5).

on the antenna simulator to the 9.0 MHz position.

(a) At ABJ1 the correct reading is -32

(15) Adjust A3L74 (fig. 3-96) for maximum rf

1 volt; if not, adjust A5R4 as required.

grid drive as indicated by the multimeter connected to

(b) At A5J2 the correct reading is -110

test point J104.

13.3 volts; if not, adjust A5R3 as required.

(16) Repeat

step

(2)

except

set

KILOCYCLES indicator to 10000 and set the rotary

0.6 volts; if not, adjust A5R22 as required.

switch on the antenna simulator to the 10.0 MHz

(2) Return the XMTR PWR switch to OFF, the

position.

POWER-LIGHTS switch to POWER OFF, disconnect

(17) Adjust A3L76 (fig. 3-105) for maximum rf

the test equipment, and return the RT-671/PRC-47 to its

grid drive as indicated by the multimeter connected to

case using the procedures of paragraph 3-11 if no

test point J104.

further adjustments are required.

(18) Repeat

step

(2)

except

set

KILOCYCLES indicator to 11000 and set the rotary

Figure 3-110. Power Amplifier Grid Drive Adjustment, Test Equipment Setup.

3-28.

Temperature

Compensated

Oscillator

(2) Connect the primary power source to the

Frequency Adjustment (fig. 3-111)

POWER connector of RT-671/PRC-47.

NOTE

(3) Connect the frequency counter to test jack

Perform this adjustment only if Radio

A6J4 (fig. 3-99) of Radio Frequency Oscillator O-

Frequency Oscillator 0-1032/PRC-47

1032/PRC-47.

(A8A6) has been repaired or

(4) On the front panel of RT-671/PRC-47, set

replaced, or if this module is

the controls as follows:

suspected of generating an incorrect

(a) KILOCYCLES indicator to 2000.

output frequency.

(b) CW-FSK/VOICE switch to VOICE.

a. Preliminary Procedures.

(1) Remove the RT-671/PRC-47 from its

(d) XMTR PWR switch to OFF.

case using the procedures of paragraph 3-11.

(e) POWER-LIGHTS switch to POWER

3-129