Emerson Keystone Figure 637, Service Manual

Page: 11 / 37

Emerson Radio
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STEP
C O N T R O L SYM BOL A D J U S T M E N T
1
Vertical
Size
R-96
Affects bottom section of
raster and overall size. A d ­
just to fill the mask verti­
cally (height).
2
Vertical
Linearity
R-100
Affects top section of ras­
ter and overall size.
Adjust
for best linearity.
3
Horizontal
Drive
R-80
Controls signal to horizon­
tal output V -19. Adjust for
best linearity.
4
Horizontal
Linearity
L-7
Affects linearity of left and
center sections of raster. Ad­
just
in conjunction with
R-80, for best linearity.
5
Horizontal
Size
L-6 Adjust to fill the mask
horizontally (width).
6
Horizontal*
Centering
R-103
Adjust to center raster hor­
izontally.
7 Focus R-55 Controls current through fo­
cus coil L-10. Adjust for
sharpest line detail.
too close to the deflection yoke as the range of
adjustment of the FOCUS control (R 55) will
be limited.
To center the raster for models provided with
a “ wobble plate” and focus levers, proceed as fol­
lows ( See figure 5 -2 ):
1) Adjust the focus lever to make the focus coil
concentric with the neck of the kinescope.
Loosen the three mounting nuts (B l, B2, B3)
slightly, if required.
2) Loosen the single wobble-plate mounting screw
(A ) and slide the plate vertically or horizontal­
ly, by means of the lever, to approximately cen­
ter the raster. Tighten the mounting screw.
3) Readjust focus coil lever, if required, to ex­
actly center the raster in the mask. Both hori­
zontal and vertical adjustments are made si­
multaneously. Tighten the mounting nuts (B l,
B2, B3) after positioning.
4) Note that normally only the vernier adjust­
ment (focus coil lever) is required, unless the
kinescope has been replaced. The wobble-
plate lever has been initially positioned at the
factory and usually will not require readjust­
ment.
c. ION T R A P : Adjust the position of the ion trap
as outlined in Section II.
5. ELECTRICAL DEFLECTION ADJUSTMENTS
— The electrical adjustment controls are located at
the rear o f the chassis. For access to the adjustment
controls, remove the cabinet back.
Use an adapter
line-cord to complete the a-c. power connections, with
the back removed.
Before proceeding with adjustment of the rear
controls, tune in a test pattern and set the front panel
controls for the best picture, as outlined in Section III.
Complete the adjustments of the deflection yoke and
focus coil before setting the electrical controls. Adjust
the controls in the order indicated.
a. A D JU STM E N T C O N T R O L S E T T IN G S :
(Table I I I).
Figure 5-2— Focus Coil Adjustments, Mechanical Centering
b. EM -PM FOCUS CO IL: For models not provid­
ed with a “ wobble plate,” adjust the upper screw
( C l ) of the focus coil to center the raster ver-
, tically. Slight variation of the two side screws
(C2, C3) may be required to complete the adjust­
ment. The focus coil should not be positioned
Figure 5-1— Deflection Yoke and Focus Coil Adjustments,
Combined Mechanical and Electrical Centering
a. D E FLE C TIO N Y O K E : If the raster lines are
not horizontal, loosen the center wingnut ( A l )
and rotate the yoke coil assembly to correct the
condition. Tighten the wingnut firmly.
The position of the assembly along the axis of the
kinescope is fixed by the two outer wingnuts (B l,
B2). The yoke should be positioned approxi­
mately at the center of the slots.
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Scanned by mbear2k - Jan 20121/17