Reassembly Procedure for Six-Step Signal Attenuator AT702

the barrel assembly. Twist the de-

the machine screw (14) and bushing

fective fixed attenuator to free its

(15).

t w o lugs from the grooves in the

(9) I n s t a l l the assembled rear fixed

connecting tube (44).

fixed plate (3) so that its notched

groove accommodates connector

Caution: Fixed attenuator values

J 7 1 8 (13). Tighten the rear fixed

a r e marked on the rear locating

plate (3) to the sleeve spacers (53)

ring (47). Bc sure to replace the

with the three machine screws (1)

f i x e d attenuator in their proper

and lockwashers (2).

l o c a t i o n s . When replacing either

(10) P u l l the front and rear movable

locating ring (37 or 47), make sure

plates (11 and 20) against the front

that the flats in the center hole of

a n d rear fixed plates (3 and 52).

each locating ring align. The three

Hold the plates in this position, and

machine screws (35 or 45) will then

tighten the two setscrews (23) that

line up with the mating holes on the

secure the bridge (24) to the sleeve

connecting tube (44).

s p a c e r s (53).

b. Reassembly Procedure for Six-Step

(11) P u s h t h e a s s e m b l e d a t t e n u a t o r

Signal A t t e n u a t o r AT702 (fig. 90).

c l o s e d . Now tighten the two set-

(1) W o r k i n g from the rear of the at-

s c r e w s (48) that secure the guide

t e n u a t o r , assemble the barrel as-

(49) to the sleeve spacer. Be sure

sembly (34). Position the assembly

to engage the groove of the guide

s o that the markings on the rear

w i t h the rear locating ring (47).

locating ring (47) face the repair-

Check for smooth riding action

man.

without binding.

(2) P l a c e the assembled bridge (24)

(12) Hold the a s s e m b 1 e d attenuator

a g a i n s t the barrel assembly (34).

c l o s e d , and orient the roller (33)

O r i e n t the spring (32) and roller

s o that it makes contact simulta-

(33) as shown in figure 90.

n e o u s l y with two of the fixed at-

(3) Slide the bridge and barrel assem-

tenuators (38) through 43). Tighten

bly together on the two sleeve

t h e screw (30), and check to see

s p a c e r s (53) and attenuator shaft

that the roller is properly centered.

( 5 6 ) , respectively; orient them as

c. Replacement of Fixed20-DB Attenua-

shown in figure 90. Do not tighten

t o r AT701 (fig. 51-52). Fixed 20-db at-

t h e setscrews (23) at this point.

tenuator AT701 is in series with the output

(4) C o n n e c t the front movable plate

o f inpulse generator G701 (fig. 51) only

(20) to the connecting link rod (19);

when the front-panel calibration switch is

u s e the machine screw (17) and

in the SHUNT CAL position. A convenient

bushing (18).

method of checking the operation of fixed

(5) S l i d e the guide (49) on the third

20-db attenuator AT701 is to set the IM-

sleeve spacer (53) as shown in

P U L S E GENERATOR DB ABOVE 1V/

figure 90. The thicker ridge of the

MC ON-OFF switch ON and to set the cali-

guide should face the front of the

bration switch to the SHUNT CAL position.

attenuator. Do not tighten the set-

Set the impulse generator coarse and fine

s c r e w (48) at this point of reas-

output controls to a high setting, such as

sembly.

80. If the panel meter on the test set shows

(6) Engage the rear locating ring (47)

a pointer deflection, this is an indication

with the groove of the guide (49).

t h a t the impulse generator is producing

an output calibrating signal; then connect

(7) Install the rear movable plate (11)

on the attenuator shaft (56) and the

one of the series-calibrated antennas (such

two sleeve spacers (53) that engage

a s the loop, vertical, or discone antenna,

the bridge (24).

depending on the tuning unit used) to the

(8) Connect the rear movable plate (11)

IMPULSE OUTPUT jack on the main unit

to the connecting link rod (16); use

f r o n t panel. Use the green color-coded

185