TROUBLESHOOTING PROCEDURES

TM 11-5820-918-13

WARNING

In the performance of some maintenance procedures, it is necessary to

have the equipment energized and dust covers removed. Extreme care

must be exercised in making internal measurements or adjustments since

potentially lethal voltages are present.

5-7.

CORRECTIVE

MAINTENANCE

5-8. The corrective maintenance data provided in this section consists of trouble-

shooting procedures and adjustment procedures. Parts requiring removal during rel-

evant adjustment operations are described and illustrated as necessary. The recom-

mended maintenance approach for the TCS-4B transmitter is repair by replacement

of assemblies. Faulty assemblies are returned to the depot for repair to a part level.

5-9. TROUBLESHOOTING PROCEDURES. Table 5-3 provides a basic guide for

troubleshooting the transmitter. The table is not intended to be all inclusive but

rather to provide indications of what unit or assembly is defective. One approach

to fault isolation is to derive all possible information from the function or malfunction

of operating controls and indicators and then, through systematic analysis of test

and measurement data, along with the troubleshooting guides, localize a fault to a

module or assembly. The malfunction is verified and corrected by replacing the faulty

assembly with a known good assembly. The performance test, paragraph 5-20, plus

figures 5-5, 5-6, and 5-7 and schematics provide the measurement data that can be

used for fault isolation.

NOTE

In order to perform troubleshooting and adjustment procedures, individual

units must be removed from rack, and top access cover must be withdrawn,

being careful to first disconnect interconnecting cables.

Table 5-2.

Preventive Maintenance Schedule

Procedure

Schedule

At installation and /or

1. Check frequency standard and adjust if necessary

per procedure given in paragraph 5-15,

after equipment has

been moved; there-

after as needed to

correct for drift.

Check battery condition by performing self-test

At beginning of each

(refer to paragraph 3-7, step p); if necessary

shift

change batteries according to paragraph 2-17.

The primary AC power should be on when

performing this test.

Check antenna RF output power efficiencies by

At beginning and end

switching power output FWD/REFL switch from

of each shift.

FWD to REFL . Note meter readings for diplexed

and non-diplexed modes. Refer to paragraph

3-8, step c.

5-2