B&K 1076, Инструкция по эксплуатации, Страница: 48 / 64

SERVICE ADJUSTMENTS
The following section will deal with the method of adjusting the various
auxiliary controls contained in the Television Analyst. Locations of these
controls can be found by raising the cover. A tube and control layout diagram
is located on the inside of this cover.
THE SYNC LEVEL control R-121, is adjusted in the following manner.
An oscilloscope is connected from pin 2 to ground of V-4A the R.F. modulator.
R-121 is adjusted for .35 volts peak to peak of sync signal. This is done with
the video gain control turned to minimum.
COLOR OSCILLATOR adjust. Capacitor C-114 is preset at the factory
and will probably not require adjustment throughout the life of the instrument.
This applies even when V-4 is replaced. If re-adjustment of this control is
necessary, it must be adjusted to set the frequency of the crystal oscillator
to 3.563795 me to an accuracy of .001 percent.
SYNC LEVEL CALIBRATE. This control determines the calibration of
the sync amplitude output control and is adjusted in the following manner.
With an oscilloscope connected to the sync output jack and the sync amplitude
control set to either -50 or +50 resistor R-215 is adjusted for 50 volts peak
to peak of sync information on the oscilloscope.
HO RIZO NT AL OSCILLATOR adjustments. There are three adjustments
required to properly set the horizontal oscillator. They are the horizontal
frequency fine, the horizontal frequency coarse and L-201 the ringing coil.
To adjust proceed as follows. Short out L-201 with a jumper lead. Set
horizontal frequency fine which is the front panel control to #5 on· the cali­
brated dial. Adjust R-211 the coarse horizontal frequency adjustment so that
the oscillator is running at exactly 15,750 cycles. A convenient method to
do this is to superimpose on a television receiver a picture from a TV station
and the picture from the Television Analyst. This can be most easily accom­
plished by having the TV receiver tuned to one channel and the Television
Analyst tuned to the adjacent channel. By adjustment of the R.F. Attenuator
the picture from the Television Analyst can be seen to float by. When the
horizontal frequency coarse control is properly adjusted the picture will be
standing straight up and thus floating by either to the right or to the left.
When this has been accomplished, remove the short across L-201 and adjust
it so that again the picture stands straight up and just floats by. This
completes the Horizontal Oscillator adjustments.
LINEARITY SIZE AND CENTERING. The adjustment for these con­
trols are described on page . . under "How to Set Up the Television Analyst."
THE VERTICAL SIZE, VERTICAL LINEARITY, HORIZONTAL SIZE
AND HORIZONTAL DRIVE controls are adjusted to provide the best possible
vertical and horizontal linearity. The Horizontal Drive control is best adjusted
by starting with the trimmer turned four full turns open from its normally
closed position. Advance the Horizontal Drive screw down until a drive bar
appears and then back off until it just disappears. This will provide the best
conditions for Horizontal Linearity.
LEAKAGE CONTINUITY TEST. Calibration is accomplished by placing
a 10 megohm resistor between the two leakage continuity jacks and rotating
the calibrate control on the front panel to the Leakage Continuity position.
R-218 the leakage continuity calibrate control inside the chassis is then ad­
justed so that the neon lamp just lights.
4.5 me OSCILLATOR adjustment. The frequency of the 4.5 me oscillator
must be adjusted with the Off-Audio-Tone switch in the "Audio" position.
If an accurate 4.5 me standard oscillator is available, then the two are brought
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