RCA Victor TRK-12, Руководство пользователя

Страница: 21 / 29

PAGE 2 7 4 - C
TRK9, TRK90, TRKI2, TRKI20
Electric Tuning Mechanism
W hen a station button is pushed in, it completes the 24-
volt circuit through the corresponding station*setting contact
and one-half of the brass selector disc, which is connected to
one side of the m otor field coil. This energizes the motor,
and the rotor is pulled forward, engaging with the gear train
th at drives the tuning condenser and selector disc. T he con-
denser and disc rotate until the insulation line comes under
the particular station'setting contact, and the m otor circuit,
is broken.
W hen the electric tuning mechanism is in action, the
motor-supply voltage is fed into a diode rectifier circuit which
applies a high bias to the first'audio amplifier. This prevents
audio amplification and. makes the set quiet or “ mute” while
the mechanism is operating.
T h e brass selector disc is fastened to the rear shaft of the
tuning condenser by means of two set-screws. W hen the
condenser is at maximum (plates fully m eshed) the. insula'
tion line should be horizontal, with the operating'end at the
left (viewed from rear). T he brass is beveled ?tt this end.
T he selector disc should be set so th at the contact'tip
plungers in the station'setting contacts project not more than
1/16'in. from the body of the contacts.
LUBRICATION
M otor bearings and gear bearings; use light machine oil.
G ear faces; use “ Pure Oil No. 611” or petroleum jelly.
Dial-Indicator pulleys and rails; use “ Castordag” o r petrO'
leum jelly.
Selector disc; apply th in film of petroleum jelly.
LUBRICATE GEARS
WITH PETROLEUM
JELLT. USE LIGHT
MACHINE OIL ON
GEAR BEARINGS.
GEAR-MESH
ADJUSTMENT STUD
(SET FOR MINIMUM
BACK-LASH AND
FREEDOM FROM
BINDING BY ROTATING
STUD)
R O L L E R .3 2 0 0 6 -
ELECTROLYTIC (A-CV
6 0 MPO.,32086 (50-60^.)
R E M O V E S P R I N G WHEI
M O T O R IS O P E R A T E D
IN V E R T IC A L POSITIO I*
MOTOR t 3 2 0 9 S ( 5 0 - 6 0 - 0
ROTOR IS PULLED FORWARD
WHEN MOTOR IS ENERGIZED
AND THE ROLLER ENGAGES
THE DISC.
DAMPER . 3 2 0 9 3 -
KNOB SHAFT
KNOB SHAFT
PULLE-Y, 31271
KNO0 SHAFT DRIVE GEAR
’ANO HUB, 312 3 9
LUBRICATE KNOB SHAFT
BEARINGS WITH
PETROLEUM JELLY
USE LIGHT MACHINE OIL-
AT MOTOR BEARINGS
PUSH BUTTON
ADJUSTER. PINS'
PILOT LI6HT
Color of Lead Color of Lead
Station To Station-Setting Station
To Station-Setting
Button Contact Button
Contact
No. 1 . No. 6 . ................... ..
Red
No. 2 .
No. 7 . .
No. 3 . No. 8 .
No. 4 .
No. 9 .•
No. 5 . ...................... Green
Figure 21— D etail o f Tuning M otor D rive
Figure 22—Electric Tuning A djustm ents
Adjustm ents for Electric Tuning
W ith power turned off, disconnect the antenna transmission
line and ground connection, turn fidelity control to radio
(3rd radio position — 6th position from. fulTcounter-clock'
wise). Remove the back from the cabinet and reconnect the
antenna transmission line and ground connection. T h e two
interlock switches on the side panels should not be touched
and care should be taken not to press on them when making
the push'button set'up. T h en turn on power, set range
selector to “ A ,” allow a few moments w arm 'up period and
proceed as follows:
1. Make a list of the desired nine stations, arranged in order
from low to high frequencies.
2. T u rn on power'volume control, turn range selector to
“ A ” band, and allow a few minutes for warming up.
3. Press down the “dial'tuning” (rig h t'h an d ) button.
4. Manually tune in the first station on the list.
5. H old down the “ dial'tuning” button and press down sta'
tion button No. 1 (left-hand1). Both buttons will stay
down. Move station adjuster contact pin N o. 1 to the
insulating line on the disc at rear of gang. W hen the
pin is correctly centered on the insulating line, the central
dial lamp will go o u t completely.
6. Press down any other button in order to release the dial'
tuning button and station button N o. \ , T une to some
other section on the dial, and then press down station
button N o. 1 again; the electric tuning mechanism will
function to tune in the first station, and the central dial
lamp will stay on.
7. Repeat this process for the remaining stations;
Figure 23— Components o f S ta tio n S ettin g Contact
Figure 24— D ial Mechanism