Calibration

TM 11-6625-922-15

regulator assembly (A5), adjust R21 so that the voltage

0-volt levels coincide. Select R61 to provide a positive

peak of the sine wave that is in phase with the positive-

is +5.0 volts dc at pin Y.

going edge of the square wave.

c. Output Amplifier Level. Operate the TRANSMIT

(2) Operate

the

MODULATION

LEVEL DBM control fully clockwise. Connect a 600-

FREQUENCY HZ switch to 83 1/3 and connect the

ohm 1-percent resistors across the tip and ring

AN/USM-182 B-channel probe to pin S of A13. Follow

terminals of 'the BAL TRANSMIT jack. Use Voltmeter,

the procedure in (1) above for selecting R63.

Electronic ME30E/U, and adjust R9 on the output

amplifier and meter amplifier assembly (A12) to obtain a

(3) Operate

the

MODULATION

voltage of 2.45 volts ac at TP1. Adjust R36 on A12 to

FREQUENCY HZ switch to 250 and connect the

obtain a voltage of 0.775 volt across the 600-ohm

AN/USM-182 B-channel probe to pin K of A13. Follow

resistor at the BAL TRANSMIT jack. Operate % MOD-

the procedure in (1) above for selecting R65.

RECEIVE LEVELTRANSMIT LEVEL switch TRANSMIT

(4) Wrap and solder the selected resistors in

LEVEL. Adjust R16 on A12 to obtain a level reading of

place.

0 dbm on the dbm/% MODULATION meter.

e. Output Amplifier-Meter Amplifier Assembly A12.

d. Percent Modulation Calibration. Operate the %

Use card extender A19 to make components accessible.

MOD-RECEIVE LEVELITRANSMIT LEVEL switch to %

Operate RANGE (KHZ) switch to 50-600. Remove

MOD. Monitor the output signal at the BAL TRANSMIT

assembly A14 from TS-2669/GCM. Connect probe from

jack with oscilloscope AN/USM-182. Operate the %

AN/USM182 to TP3 on A12. Select R70 on A12 to

MON ADJ control to obtain a 50-percent modulated

obtain a dc voltage level on TP2 to 0 to +0.1 volt dc.

waveform on the AN/USM-182. Adjust R4 on Modulator

Wrap and solder R70 in place. Replace assembly A14

meter adjust assembly A20 to obtain a reading of 50-

in TS-2669/GCM.

percent on the dbm/% MODULATION meter.

f. Input Amplifier-Demodulator Assembly A6. Use

e. Sweep Drive Baseline. Operate SWEEP TIME

card extender A19 to make components accessible.

control counterclockwise (ccw) toward the 1 SEC

With no input signal connected to either RECEIVE jack,

position. Operate the SWEEP CALIBRATE switch to

connect probe from Oscilloscope AN/USM-182 to TP2

LOW CAL. On sweep drive assembly A16, monitor TP1

of A6. Select R40 to obtain +0.5 volt dc 0.2 volt at

with Oscilloscope AN/USM-182. Adjust R4 so that the

TP2. Wrap and solder R40.

voltage at TP1 does not vary around ground by more

than 2 millivolts when the SWEEP WIDTH control is

6-7. Calibration

operated from fully ccw to fully cw. Operate the

a. Initial Conditions. Allow at least a 20 minute

SWEEP CALIBRATE switch to SWEEP and monitor the

warmup time before any adjustments. Operate the front

triangular waveform at TP1 with the AN/USM-182.

panel controls as follows:

Adjust R51 on A16 so that the most positive excursion

Switch

Position

of the triangular waveform is at ground, and note the

RECEIVE IMPEDANCE

600

level of negative excursion. Operate the SWEEP

TRANSMIT IMPEDANCE

600

CALIBRATE switch to HIGH CAL. Adjust R52 on A16

REF RETURN-END TO

END TO END

so that the dc level at TP1 is the same as noted for the

END

most negative excursion of the triangular waveform 3

TRANSMIT FREQUENCY- TRANSMIT FREQUENCY

millivolts.

RECEIVE FREQUENCY

f. Vfo Frequency Calibration. The adjustments for

MODULATION FRE-

variable frequency oscillator assembly A2 are located by

QUENCY HZ

removing the bottom cover of the TS-2669/GCM.

COUNTING TIME

1 SEC

Connect Frequency. Meter AN/TSM-16 to connector

SWEEP-CARRIER-REF-

CARRIER

XA16 pin T.

ERENCE

(1) Operate SWEEP-CARRIER-REFERENCE

CARRIER FREQUENCY

Set for approximately 10

switch to CARRIER and CARRIER FREQUENCY

kHz.

control fully ccw. Adjust capacitor C7 on A2 to obtain a

OUTPUT LEVEL DBM

reading on the AN/TSM-16 of 200,000 Hz.

RECEIVE LEVEL DBM

(2) Operate SWEEP-CARRIER-REFERENCE

b. Power Supply Voltages. On +12- and -12-volt

switch

REFERENCE

and

REFERENCE

regulator assembly All, adjust R37 so that the voltage is

FREQUENCY control fully ccw. Adjust

+12.0 volts dc at pin Y; and adjust R34 so that the

voltage is -12.0 volts dc at pin D. On the +5-volt

6-3