Alignment of 455-Kc If. Amplifier

o h m termination series unit. The

output end of this coaxial cable is

a BNC-type UG-88/U connector

(male).

(3) Since many jacks and plugs within

the tuning unit are rob-type minia-

ture c o a x i a 1 connectors, a type

47250 adapter (para 81) is required

f o r interconnecting the output of

t h e tuning unit 1 signal generator

t o input comector P4 of the if.

amplifier.

(4) Disconnect plug P4 (fig. 56 and 60)

from jack J3 on the if. step atten-

b. Allow the tuning unit, the main unit,

uator.

and the tuning unit 1 signal generator to

warm up for at least 1/2 hour before start-

(5) Connect plug P4 to the type 47250

ing alignment.

a d a p t e r . This step completes the

c. Set the front panel controls as follows:

procedure for injecting the 455-kc

output of the tuning unit 1 signal

g e n e r a t o r to the input of the if.

amplifier.

b. Vary the output control of the tuning

unit 1 signal generator so that an onscale

indication can be seen on the DECIBELS-

M I C R O V O L T S (panel meter) of the main

unit.

Note: As tuning unit 1 is brought into alignment,

decrease the tuning unit 1 signal generator output

and the tuning unit GAIN control (i f necessary) so

t h a t the pointer on the panel meter maintains an

onscale indication.

c. Reference to figure 56 shows that the

455-kc if. amplifier is mounted within the

85. Alignment of 455-Kc If. Amplifier

tuning unit in an inverted position. Adjust

(fig. 56)

t h e variable cores of T31, T32, T33, and

T34, in this sequence, for a maximum out-

a. Rotating the band switch to band 1 or

put indication on the panel meter.

3 energizes the 455-kc if. amplifier and

d. Adjust the variable cores at the tops

r e m o v e s operating power from the 1,600-

of T29, T31, T32, and T33, in this sequence,

kc if. amplifier. Set the frequency dial of

for maximum output.

the tuning unit 1 signal generator (such as

e. Repeat the procedures given in c and

signal generator, General Radio Co., type

d above for final peak adjustments.

1001-A standard) to 455 kc. Apply the un-

f. D i s c o n n e c t p l u g P 4 f r o m t h e t y p e

modulated output of the tuning unit 1 signal

47250 adapter and reconnect P4 to jack J3

generator to the input of the if. amplifier

on the if. step attenuator.

as follows:

(1) T e r m i n a t e t h e a t t e n u a t o r o u t p u t

86. Alignment of 1,600-Kc If. Amplifier

jack of the tuning unit 1 signal gen-

e r a t o r with the type 1000-P2 40-

a. Rotating the band switch to bands 2,

o h m s e r i es unit, which is an

4 , 5, or 6 energizes the 1,600-kc if. am-

accessory supplied with the tuning

p l i f i e r and removes operating power from

unit 1 signal generator.

the 455-kc if. amplifier. The test setup is

(2) C o n n e c t the type 874-R22 coaxial

similar to that described in para 85 except

c a b l e (an accessory of the tuning

for setting the frequency dial of the signal

unit 1 signal generator) to the 40-

generator to 1,600 kc.

193