Section VI. ELECTRONIC INTERFACE ASSEMBLY TROUBLESHOOTING

TM 9-1270-212-14&P

Section VI. ELECTRONIC INTERFACE ASSEMBLY TROUBLESHOOTING

NOTE

4-19. General.

If all suggested corrective action procedures and

This section provides troubleshooting procedures for the

all circuit card tests do not correct abnormal

EIA by using the test set. The tests are performed on the

indications, check the EIA wiring (see foldout

bench or in the helicopter with the EIA disconnected from

FO-4 or FO-5). To check the wiring, use a

the helicopter and other HSS LRU connectors. Individual

separate multimeter.

tests of the buffer amplifiers and the plug-in circuit cards

follow the EIA checkout procedures.

4-21. Troubleshooting Buffer Amplifier Modules A1

4-20. EIA Checkout Procedures.

Through A8.

NOTE

Modules Al through A8 are identical. Test each module

by the following procedure:

Where the procedures for checking out an EIA

used in XMl28 differ from those for an EIA

a. Perform the test-set preliminary procedures

used in XMl36, these differences are spelled

(paragraph 4-13).

out in detail in the test table in this paragraph.

Refer to figure B-10, foldouts FO-4 and FO-5,

b. Connect the module to be tested to the J10 BUFFER

and the identification plate on the EIA to

AMPL jack on the test set.

determine which EIA is being tested.

a. Perform the test-set preliminary procedures

c. Set the POWER switch to ON-60 HZ if a 60-Hz

(paragraph 4-13).

power source is used or to 0N-400 HZ if a 400-Hz power

source is used.

b. Connect PI and P2 of test cable W2 to J1 and J2 of

the test set.

d. Set the multimeter range switch to 10 and the

function switch to AC V.

c. Connect the other connectors of test cable W2 to the

EIA as follows:

e. Perform the tests in table 4-6. If a failure occurs, the

buffer amplifier is defective and should be replaced.

P3 to Jl

4-22. Troubleshooting Sequencer Card A9.

P4 to J2

a. Perform the test-set preliminary procedures

P6 to J4

(paragraph 4-13).

P5 to J3.

b. Connect card A9 to the J7 SEQUENCER CARD

receptacle on the test set.

d. Set the POWER switch to ON-60 HZ if a 60-Hz

power source is used or to ON-400 HZ if a 400-Hz power

c. Set the POWER switch to ON-60 HZ if a 60-Hz

source is used.

power source is used and to ON-400 HZ if a 400-Hz power

source is used.

e. Set the multimeter range switch to 100 and the

function switch to DC V.

d. Perform the tests in table 4-7. If any of the tests fail,

sequencer card A9 is defective and should be replaced.

f. Perform the procedures in table 4-5.

NOTE

Where reference is made in the table to "card

Al 0 or Al 5," check card Al 0 if the EIA is

from XMl28 and card Al 5 if the EIA is from

XM136.

4-25