Line Current Adjustment (TT-537/G)

TM 11-5815-206-12/ TO 31W4-2PGC1-61

until the page printer begins to print errors. Note

(circuit that is connected to terminals 3

the dial position at that point.

and 4). The value of current in the send

(3) Turn the ARMATURE dial clockwise

c i r c u i t (circuit that is connected to ter-

S lowly until the page printer resumes printing

minals 1 and 2) must be adjusted by the

correctly. Continue turning the dial clockwise until

operator at the distant end of that circuit.

the page printer again begins to print errors. Note

d. Receive-Only Operation (A, fig. 2-8). Turn

the dial position at that point.

the LINE INCREASE knob clockwise slowly until

(4) Set and lock the ARMATURE dial

the pointer indicates 60 ma on the meter scale.

m i d w a y between the two readings ((2) and (3)

2-18. Line Current Adjustment (TT-537/G)

above).

After the signal line connections are made and the

b. RANGE Dial Preliminary Adjustment.

c o m p u t e r is energized to provide a continuous

CAUTION

marking condition on the line, adjust the LINE

Never change the position of the RANGE

until

the

potentiometer

INCREASE

dial while the page printer is idle.

MILLIAMPERES meter indicates 20 ma.

(1) Loosen the RANGE dial lock and turn the

2-19. Line Current Adjustment (TT-698(*)/TG)

R A N G E dial counterclockwise slowly until the

page printer begins to print errors. Note the dial

the

TT-698(*)/TG

the

line

current

position at that point.

established by the input circuit resistance of the

(2) Turn the RANGE dial clockwise slowly

receiver module. The line current is approximately

until the page printer resumes printing correctly.

100 micro-amperes. The LINE INCREASE control

Continue turning the dial clockwise until it again

is used on TT-698(*)/TG, low level units to adjust

begins to print errors. Note the dial position.

the selector magnet current to an optimum value.

( 3 ) Set and lock the RANGE dial midway

W i t h either a continuous mark test signal or

between the two readings (1) and (2) above.

A1TB1, terminals 1 and 2 jumpered to terminals 4

c. A R M A T U R E D i a l F i n a l A d j u s t m e n t . T h i s

and 5 and the keyboard stopped, adjust the LINE

adjustment is identical with the ARMATURE dial

INCREASE potentiometer until the DC

preliminary adjustment (a above) except that it is

MILLIAMPERES meter indicates exactly 20mA.

p e r f o r m e d after t h e R A N G E d i a l p r e l i m i n a r y

2-20. ARMATURE and RANGE Dials Adjust-

adjustment (b above) and that step in a(1) above is

ment

omitted.

(fig. 3-1)

d . RANGE Dial Final Adjustment. T h i s a d -

NOTE

justment i s i d e n t i c a l w i t h t h e R A N G E d i a l

Be sure the line current is of the proper

preliminary adjustment (b above) except that it is

value (para 2-17) before this adjustment is

p e r f o r m e d after the ARMATURE dial final a d -

made. On the TT-698(*)/TG, insure the

justment.

selector magnet current is set at the op-

2-21. Installation Final Test

timum value (para 2-19).

After installation, perform a complete operational

The ARMATURE and RANGE dials, as shown in

test of the teletypewriter before beginning the

figure 3-1, are associated with the page printer

transmission of official traffic.

portion of the teletypewriter. Continuous reception

a. Make the checks listed in the equipment

of test signals (usually alternate R and Y signals,

performance check list, as described in paragraph

transmitted from the distant station) is necessary

4-8.

for adjustment of these dials. Arrange to have

b. Have the distant operator transmit a test

these signals transmitted from the distant station

message and observe the typewritten copy. The

and adjust the dials as described in a through d

c o n v e n t i o n a l test message is as follows: "THE

below.

QUICK BROWN FOX JUMPED OVER THE

a. ARMATURE Dial Preliminary Adjustment.

LAZY DOG's BACK 123456789 -$!"( )"/-.;?,.".

(1) L o o s e n t h e R A N G E d i a l l o c k , s e t t h e

c. Transmit the same test message to the

RANGE dial at 65, and tighten the dial lock.

d i s t a n t station for a performance test of the

( 2 ) Loosen the ARMATURE dial lock and

equipment at the distant station.

turn the ARMATURE dial counterclockwise slowly

2-12