Emerson Keystone Figure 637, Руководство по обслуживанию

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Emerson Radio
6) Rotate the BRIGH TN ESS control to the max­
imum counter-clockwise position and then ad­
just slowly clockwise until light is just visible
on the screen. Rotate in reverse direction un­
til light just vanishes.
7) Adjust the C O N TR A ST control until a pic­
ture appears on the screen and desired con­
trast is attained.
A further reduction in the
BRIGH TN ESS control setting may improve
the apparent contrast of the picture.
8) If the picture moves vertically or horizontally,
make the adjustment indicated in steps 9 and/
or 10.
9) Adjust the V E R T IC A L H O LD control until
the picture stops moving up or down. Proper
operating setting of this control is in the cen­
ter of the range over which the picture remains
stationary.
10) Adjust the H O R IZ O N T A L H O LD control
until picture stops moving from side to side.
11) Readjust the C O N TR A ST control until the
desired picture intensity is obtained. It may
be necessary o readjust the BRIGH TN ESS
control slightly at the same time for optimum
brilliance.
12) After the receiver has been operating for some
time, it may be necessary to readjust the T U N ­
ING control slightly for best picture quality.
b. CHAN GIN G ST A T IO N DU RIN G O P E R A ­
T IO N :
1) Set the SELECTOR control to the proper
channel number.
2) Readjust the T U N IN G control if necessary to
obtain best picture quality.
3) Readjust the C O N T R A ST control slowly un­
til the desired picture quality is obtained.
4) Readjust V O L U M E to suitable level.
5) Readjust B R IG H TN ESS control for desired
brilliancy.
c. CHECKING O P E R A T IO N : The use of auto­
matic frequency control in the sync circuits of
the receiver makes readjustments of the V E R ­
T IC A L H O LD and H O R IZ O N T A L H O LD
controls infrequent provided the control set­
tings for proper operation are not disturbed.
Figures 3-2 through 3-9 indicate correct and
incorrect adjustment of the various controls.
Proper operation may be obtained by operation
of the associated control.
Section 4.
C I R C U I T D E S C R I P T I O N
1. GENERAL— Chassis 120110B and 120113B are
basically alike; the latter is modified to accommodate
a 12-inch kinescope and contains some changes in the
high-voltage power supply circuits. Both chassis con­
tain twenty-three tubes including the kinescope and
low-voltage rectifiers. The chassis use the intercarrier
method of sound reception, with the 4.5 me. audio i-f
produced by heterodyning the video and audio carriers
at the output of the video detector. The various stages
of the receivers are indicated in the block diagram, fig­
ure 4-1.
9552 95
Figure 4-1— Block Diagram, Chassis 120110B, 120113B
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