Rf Chart

Signal

Possible

trouble

Connection to

frequency

(kc)

---------

V9 second if. amplifier grid, pin 1

Defective V9. open R72 or R73: or shorted

455

C145, C147.

V8 first if. amplifier plate, pin 5 ----- ----- -

Defective or misaligned T31 network; open

455

R69, R71, R88, or K89, feedthru capacitor

C142, or coupling capacitor C144: shorted

C137, C139, or C143.

V8 first if. amplifier grid, pin 1. --------------

Defective V8: open R65 or R66; shorted

455

C130, C131, C135, or C136.

If. interstate transformer T29, terminal 4

Defective T29; open R42, R43, R44, R64, or

455

(fig. 62).

C133; shorted C129, C133.

V2 mixer plate, pin 1 - - - - - - ------ --------

455

Defective if. input selector (fig. 59), cable

assembly W1, or if. step attenuator AT1

(fig. 60); open connection between jack J3

and mating plug P4; shorted termination

CP3 on 455-kc if. amplifier (fig. 62);

or open R62 at input to interstate trans-

former T29.

Input jack J4 on if. output selector (fig. 63).

1,600

If 455-kc test at input jack J5 on if. output

selector checked out satisfactorily, trouble

Disconnect plug P5 from mating jack J4 and

is localized to if. output selector itself.

inject signal from external signal generator.

Isolate trouble by referring to trouble-

shooting chart (para 67) for tuning unit 1.

Defective or misaligned T28 network or ter-

1,600

V7 fourth if. amplifier plate, pin 5 -----------

mination CP2; open or shorted B+ feed-

Caution: Reconnect plug P5 to mating jack

thru capacitor C90; open R23, shorted C124;

J4 on if. output selector before starting this

or trouble in contact 2, 4, 5, or 6 (depend-

test.

ing on band in use) and wiper (W) of MEGA-

CYCLES band switch S1 (rear).

V7 fourth if. amplifier grid, pin 1 - - - - - - - - - -

Defective V7; open R58 or R59: or shorted

1,600

C119, C122.

V6 third if. amplifier grid, pin 5 - - - - - - - - - - -

Defective or misaligned T27 network; open

1,600

R57: or shorted C117.

Defective V6; open R55 or R56; or shorted

1,600

V6 third if. amplifier grid, pin 1 -------------

C113, C115.

V5 second if. amplifier plate, pin 5 - - - - - - - - -

Defective or misaligned T25 network; open

1,600

R54; or shorted C111.

Defective V5; open R49, R52, or R53; or

1,600

V5 second if. amplifier grid, pin 1 -----------

shorted C104, feedthru capacitor C105, or

bypass capacitors C107 or C108.

V4 first if. amplifier plate, pin 5 - - - - - - - - - - -

Defective or misaligned T25 network; open

1,600

R51; or shorted C99 or C101.

- - - - - - -----

Defective V4; open R47 or R48; or shorted

1,600

V4 first if. amplifier grid, pin 1

C96 or C97.

Defective T24; open C93 or R46; open or

If. interstate transformer T24 at ungrounded

1,600

shorted feedthru capacitor C91; shorted

terminal of primary winding.

bypass capacitors C92 or C94.

V2 mixer plate, pin 1 ------ ------ ------ ---

If 455-kc test at mixer plate checked out

1,600

satisfactorily, trouble is localized to relay

K1 or interstate transformer within if. in-

put selector (fig. 59); or to selector relay

K5 within if. step attenuator AT1 (fig. 60);

open connection between jack J2 on if.

step attenuator and mating plug P3 (fig.

60); detective termination CP1 on 1,600-

kc if. amplifier (fig. 61); or open R45 at

input to interstage transformer T24.

c. Rf Chart (fig. 57 and 58). After com-

the chart below. Use the tuning unit 1 sig-

nal generator (para 65) with 400-cps mod-

pletion of the tests listed in b above shows

that the trouble is not in the if. output se-

ulation. Check each of the six bands and

lector, the 455- or 1,600-kc if. amplifier,

each of the six turret tuner segments (fig.

t h e if. step attenuator, or the if. input

58) by rotating the MEGACYCLES switch,

p o s i t i o n by position, to correspond with

s e l e c t o r , proceed with the tests listed in

156