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the screen for ease and accuracy in perforrning adjustrnents. It is preferable that the ad-
justments be rnade with the receiver in the location where it will be used. However, ad-
justments rnust be checked and readjusted if necessary, with the receiver in the final loca-
tion, position, and with the sarne light conditions under which it will be viewed. This is
necessary because of the affect of the earthrs rnagnetic field and other external rnagnetic
fields upon color purity and convergence. For exarnple, a color receiver that is properly
adjusted facing a particular direction, rnay reproduce faithful colors. If this receiver is
turned or ry1! to face in another directlon, purity and gyg.ry, rnay now be out of ad-
justrnent. The extent of the effect of rnoving the receiver after if is set up will vary from
set to set and location to location.
TIMITS OF PURITY AND CONVERGENCE
Perfect convergence norrnally cannot be obtained over the entire screen area. Picture
tube and deflection yoke developrnent of present-day design lirnit this condition, but it
should be understood that with careful and accurate adjustrnents, a very good convergence
covering at least 85% of the screen area can be achieved.
Good convergence in the four corners of the raster rnay not be obtained, but if..85% (plus or
rninus 5%l of. the total area is accurately converged, this is considered a norlTral, acceptable
condition.
The present-day color picture tube also lirnits color purity. I4rith careful and accurate
adjustments, good color purity can be achieved for each o{ the three fields with good black
and white reproduction. Very smalL areas of irnpurity at any of the four corners 6r sides
of the raster are considered acceptable.
BTACK AND WHlTE TR,ACKING
The black and white tracking adjustment is another irnportant consideration. If properly
rnade, the color set will produce black and white pictures within the norrnal useable range
of both lhe Contrast and Brightness controls. If the adjustrnent i" ir,Effii,TGtiE[T.-
ture wllI appear tinted and the color will vary at different Brightness and Contrast control
s etting s .
Cornplete TTBLACK AND WHITE TRACKING'| instructions are contained in the "COLOR
SET-UP ADJUSTMENTS" on page II.
DEATER AND CUSTO}TER INSTRUCTION
The Operating Instructions packed with the receiver should be reviewed with all those
who will operate and use a color television set. The expected perforrnance and lirnita-
tions of the color set should also be explained to the dealer or customer. This will help
thern rrunderstandrt their color receiver.
DEMAGNETIZING IHE COLOR PICTURE TUBE
Satisfactory purity and/or convergence of a color receiver rnay be difficult or irnpos-
sible to obtain if the metal parts of the picture tube or chassis have become magnetized.
Therefore, a dernagnetizing or degaussing procedure should be perforrned before making
the Color Set-Up Adjustrnents. Instructions on how to make a dernagnetizilrg coil are given
under "DEMAGNETIZING COIL" on page 49.
ANTENNA REQUIRTMENTS
The antenna requirernents for color reception are rnuch rrrore critical than for black and
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