CHAPTER 3 DIRECT SUPPORT MAINTENANCE INSTRUCTIONS

11-5835-243-34/EE641-AA-MMl-010/E154

MTT/TO

31S3-4-110-1

CHAPTER 3

DIRECT SUPPORT MAINTENANCE INSTRUCTIONS

Section I. GENERAL

specific failure or unserviceable condition and

3-1. Scope

restoring the tape transport to a serviceable con-

This chapter provides maintenance instructions for

dition.

direct support level personnel. Direct support

maintenance is performed by those maintenance

3-2. Voltage Measurements

activities designated to support the using

Voltage, resistance, and continuity measurements

organization and emphasizes corrective main-

are made by direct support maintenance personnel

tenance at the equipment site. Corrective main-

for troubleshooting faults which cannot be resolved

tenance is performed on items which are identified

or repaired by means of the troubleshooting charts.

as faulty by organizational maintenance personnel,

Normally such faults are traceable to wiring or

but are beyond their capability to correct using the

chassis-mounted components. Generally, signal

maintenance resources authorized at the

voltages are at standard TTL logic levels and

organizational maintenance level. Direct support

measurements are made using an oscilloscope.

maintenance personnel also provide technical

Power supply voltages are measured with a

assistance to the using organization in all areas

multimeter.

which require skills and training that are beyond the

capabilities of the organizational maintenance

3-3. Waveforms

personnel. Direct support maintenance activities

All logic levels and waveforms are obtained at the

are described below.

test points located on the front edge of each card.

a. Visual inspection of components for evidence of

potential failure conditions such as lack of

3-4. Verification of Repair

cleanliness, improper seating of connectors, loose

After a fault has been isolated and corrected, the

hardware or other items, discoloration due to ex-

repair must be verified before returning the tape

cessive heat, and frayed cables or wiring. Correction

transport or magnetic tape cartridge to the using

of observed conditions will be accomplished as

organization. Perform the functional tests in

necessary at the time of observance by the main-

paragraphs 3-9 through 3-17 to verify the per-

tenance personnel authorized to perform the task.

formance of the tape transport, or paragraphs 3-18

b. Replacement of an unserviceable subassembly,

and 3-19 to verify the performance of the magnetic

module, or assembly with a known good

tape cartridge.

subassembly, module or assembly.

c. Performance of the repairs required to correct a

Section II. TOOLS AND EQUIPMENT

3-6. Repair Parts

3-5. Tools and Test Equipment

Tools and test equipment required to perform the

Repair parts authorized for use by direct support

maintenance procedures in this chapter are listed in

maintenance personnel for the tape transport and

magnetic tape cartridge are listed in the Repair

the Maintenance Allocation Chart (MAC) located in

Parts and Special Tools List (RPSTL), TM

TM 11-5805-681-12-1 and TM 11-5805-683-

12-1. Any tools or test equipment authorized for

11-5835-243-34P. Direct support maintenance

use at the organizational level are also authorized

personnel are also authorized to use repair parts

for use by direct support.

listed in TM 11-5835-243-20P.

3-1