Section Ill. TROUBLESHOOTING

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

MTT/TO

31S3-4-110-1

Section Ill. TROUBLESHOOTING

through A5. Use the circuit card schematic

3-7. Introduction

diagrams, signal interconnecting list, and in-

This section contains the direct support fault

terconnecting wiring diagrams, figures FO-2

isolation procedures required to identify and correct

through FO-11 for signal tracing. In addition,

a tape transport or magnetic tape cartridge

selected waveforms and timing information is

malfunction. Fault isolation by direct support

illustrated in figures 2-4 and 2-5. Table 3-3 lists

maintenance personnel is based on a series of

operating voltages for the power amplifier circuit

functional tests using the Magnetic Tape Transport

card assembly A9.

Test Set TS-4002/UYH-5 (hereafter called the

exerciser). Some of the tests also use the Magnetic

3-9. Tape Transport Test Setup

Tape Test Cartridge TW-433/UYH-5 (hereafter

a. Connect tape transport to exerciser shown in

called the skew tape cartridge), while others require

figure 3-1.

only a standard tape cartridge.

b. Install a standard tape cartridge in the tape

3-8. Fault Isolation

transport and lock in place. Be sure write protect

detent is not in PROT position.

Isolation to a replaceable component is ac-

c. Refer to TM 11-6625-3024-14 for exerciser

complished by using the troubleshooting charts

operating instructions. Set exerciser controls as

(tables 3-2 and 3-4) in conjunction with the test

follows:

procedures located in paragraphs 3-9 through 3-19.

POWER ON/OFF

These tests are arranged in a logical order of func-

SYSTEM

tions and must be performed in the sequence in

Depress PROCESSOR

Verify STOP indi-

which they appear. If the tape transport or cartridge

RESET

cater is ON.

fails a test, stop testing immediately and refer to the

(located on connector

If not, depress

appropriate troubleshooting chart for the repair

panel)

RESET again.

procedure. When the repair has been accomplished,

SELECT 1

repeat the entire test to verify the repair. In some

POWER ON/OFF

cases it may be necessary to trace signals with an

TRANSPORT

oscilloscope or multimeter in order to isolate a fault.

An extender card is provided in the IL Accessories

Set for accessing the test points on circuit cards Al

3-2