Automatic Positioner Functions

cuit. As the rear wafer of S1203

b. When the MANUAL FREQUENCY

rotates from 0 to 9, the front wafer

TENS control is turned from 22 to 23, the

detent supplies a momentary

following sequence occurs:

ground to relay K1201 through con-

(1) The ground circuit to the 10.0-

tact B of S1203, which causes the

mc automatic positioner relay

10.0-mc automatic positioner to

K1201 is completed through con-

recycle.

tacts A and 22 of the 10.0-mc seek-

(3) TENTHS switch S708 controls the

ing switch contacts S1201, contacts

9 and 10 of CHAN SEL selector

.l-mc automatic positioner in the

switch contacts S705A, contacts

same manner as the UNITS switch

22, 32, and F of TENS switch S706,

controls the 1.0-mc automatic

and contacts 20 and 21 of CHAN

positioner. Relay K1203 is kept

SEL selector switch S705A. All

energized by the ground circuit

other contacts of S1201, except

through contacts A and .6 of switch

contacts 23 and 33, are also

S1204 and contacts .6 and 12 of S708

grounded through similar circuits

until the .1-mc seeking switch de-

not shown on the simplified

tent reached the .6 position.

schematic.

(2) Relay K1201 energizes and causes

86. Automatic Positioner Functions

the 10.0-mc automatic positioner

a. The 18-position, 10.0-mc automatic

to operate as described in para-

positioner controls the rotation of the

graph 83 b. Switch S1201, ganged to

tuning shaft within the uhf injection sys-

the 10.0-mc automatic positioner,

tem subunit. When the tuning shaft turns,

rotates counterclockwise until the

it changes the positions of the crystal and

rotor contact reaches contact 23.

coil switches, S201 and S202 (fig. 6), the

Although contact 33 (180 from

variable capacitors and the tuning coils t

contact 23) is also ungrounded,

tune the radio set to the selected frequency.

relay K1201 is kept energized dur-

The 10.0-mc automatic positioner tunes the

ing that phase of the cycle by the

uhf injection system from 200 to 370 mc in

ground circuit through phasing and

10.0-mc steps.

blanking switch contacts 7 and 17 of

b. The 10-position, 1.0-mc automatic

of S1202 and contacts C and F of the

positioner controls the rotation of one of

TENS switch. Similarly, if the

the tuning shafts within the first if. ampli-

TENS control S706 were set to 33,

fier subunit. This tuning shaft is coupled to

the 10.0-mc seeking-switch detent

second oscillator crystal switches S301

would not stop at position 23. Dur-

and S302 and tuning coil L310 (fig. 9). When

ing that phase of the 10.0-mc seek-

it turns, the tuning shaft changes the posi-

ing-switch cycle, the ground cir-

tions of the crystal switches and the tuning

cuit to relay K1201 would be

coil to tune the output of the second oscil-

completed through contacts 2 and

lator from 17.0 to 26.0 mc in 1.0-mc steps.

17 of S1202 and contacts G and F

c. The 10-position, 0.1-mc automatic

of S706 front.

positioner controls the rotation of the

C. When UNITS switch S707 is turned to

tuning shaft within the second if. subunit.

8, the sequence described in (1) and (2)

This tuning shaft is coupled to third oscil-

below occurs :

lator crystal selector switches S401 and

(1) The ground circuit to the 1.0-mc

S402 (fig. 10), and the tuning coils within

automatic positioner relay K1202

bandpass filters Z401, Z402, and Z403

is completed through contacts A

(fig. 10). When the shaft turns, the output

and 8 of S1203 and 8 and 12 of S707.

of the third oscillator, V401B, and the

(2) Switch S1203 is ganged to the 1.0-

bandpass filters Z401, Z402, and Z403 is

mc automatic positioner and ro-

changed from 3.0 to 3.9 mc in 0.1-m

tates until the detent reached

steps.

position 8 and opens the ground cir-