Figure 3-1. Meter, Modulation ME-57A/U, controls, indicators, and connectors.

TM 11-6625-2629-14&P

Figure 3-1. Meter, Modulation ME-57A/U, controls, indicators, and connectors.

Section II. OPERATION UNDER USUAL CONDITIONS

CAUTION

to the range containing the input signal

frequency.

Insure that the DEVIATION RANGE

f. Set the FREQUENCY MC dial to the ap-

KC switch is in the 1000 TUNE position

proximate frequency of the expected signal; use

b e f o r e energizing the equipment or

the TUNING knob.

damage to the DEVIATION meter may

result .

3-4. Operating Procedure

3-3. Preliminary Starting Procedures and Initial

NOTE

Adjustments

If an abnormal indication is obtained

during the operating procedure, refer to

Before power is applied to the modulation meter,

the troubleshooting chart Table 4-3.

perform preliminary operations listed below.

Operate the equipment as follows:

u. Check the line voltage selector switch and be

a. Check the controls to be sure that they are

sure that it is set to the correct liner voltage. Be

set as required by the preliminary starting

sure that the proper fuses are in use. Use a 2-

ampere fuse for 115-volt operation, and a 1.

b. Set the POWER switch to the ON position

ampere fuse for 230-volt operation.

b. Plug the modulation meter into the power.

and allow 30 minutes for warmup.

source.

c. Measure deviation from either side of the

c. Set the TUNE-FINE TUNE switch to the

resting frequency as follows:

TUNE position.

(1) Connect an unmodulated carrier to the

d. Set the DEVIATION RANGE KC switch to

INPUT connector of the modulation meter.

the 1000 TUNE range.

(2) Rotate the TUNING knob until the

e. Set the FREQUENCY RANGE MC switch

CARRIER SHIFT meter indicates zero.

3-2