Section II. TROUBLESHOOTING, REPAIR, AND ADJUSTMENT

TM 11-6625-922-15

Sequence

No.

Item to be inspected

Procedure

References

af. DELAY METER RANGE MS

switch to .15 -.5.

ag. FINE DELAY MS switch to 1 (black).

ah. COARSE DELAY MS switch to 0.

ai. Operate DELAY ZERO ADJ

control to obtain DELAY meter

reading of 0 on black 0 - .5 MS

scale.

aj. DELAY METER RANGE MS

switch to 3 - 10.

ak. DELAY meter should read 1 MS

on black 0 - 10 MS scale.

Section II. TROUBLESHOOTING, REPAIR, AND ADJUSTMENT

based on symptoms which would be obtained while

4-5. General

performing the operational checks in the preventive

maintenance checks and services (paras 4-2, 4-3 and 4-

Replacement and repair of the major unit and

4). When an abnormal indication is obtained, locate the

subassemblies of this equipment are authorized for the

symptom in the troubleshooting chart and perform the

various categories of maintenance personnel as

corrective measure indicated. If the corrective measure

indicated in section II of the maintenance allocation

does not correct the trouble, refer the equipment to

chart (app C). The tools and test equipment required

higher category maintenance personnel.

are listed in section III of the maintenance allocation

chart. The troubleshooting information (para 4-6) is

4-6. Organizational Troubleshooting

Item No.

Symptom

Possible trouble

Corrective measure

POWER ON indicator fails

a. Failure of primary power source.

a. Restore primary power source to

to light.

operable condition, or obtain

new primary source.

b. Blown fuse.

b. Replace fuse (fig. 3-1).

c. Defective indicator lamp.

c. Replace indicator lamp (fig. 3-1).

d. Loose ac connection.

d. Secure all ac connections.

dbm/% MODULATION

a. Meter amplifier not operating.

a. Replace assembly A12.

meter shows no indication

b. Low-pass filter not operating.

b. Replace assembly A13.

(para 4-4 sequence 11 ).

c. Countdown logic not operating.

c. Replace assembly A10.

d. 2 MHz oscillator not operating.

d. Replace assembly A4.

e. Front panel control defective.

e. Refer to higher level of

maintenance

dbm/% MODULATION

a. Sweep drive circuitry defective.

a. Replace assembly A16.

meter shows no indication

b. Modulator or mixer circuit defective. b. Replace assembly A14 or A15.

(para 4-4 sequence 11o).

c. Vfo circuit defective.

c. Refer to higher category of

maintenance.

d. Front panel control defective.

d. Refer to higher category of

maintenance.

FREQUENCY display does

a. Time base or reset generating cir- a. Replace assembly A10.

not read at all or reads

cuits inoperative.

erratically (para 4-4,

b. Vfo circuits defective.

b. Refer to higher category of

sequence 11q).

maintenance

c. Display circuit defective.

c. Refer to higher category of

maintenance.

FREQUENCY display does

a. Modulator/mixer circuit defective.

a. Replace assembly A14.

not read 10000 (para 4-4,

b. Sweep drive circuitry defective.

b. Replace assembly A16.

sequence 11s).

FREQUENCY display does

a. Sweep drive circuitry defective.

a. Replace assembly A16.

not indicate frequency

b. Vfo circuitry defective.

b. Refer to higher category of

sweep (para 4-4, sequence

maintenance.

11aa).

4-4