SECTION 3 SET-UP ADJUSTMENTS
•When complete readjustment is necessary or a new picture tube is installed, carry out the following adjustments.
•Unless there are specific instructions to the contrary, carry out these adjustments with the rated power supply.
•Unless there are specific instructions to the contrary, set the controls and switches to the following settings :
Contrast | 80% [or remote control normal] |
Brightness | 50% |
Carry out the adjustments in the following order :
Note : Test equipment required.
1.Color bar/pattern generator.
2.Degausser.
3.Oscilloscope.
4.Digital multimeter.
Preparation:
1.In order to reduce the influence of geomagnetism on the set’s picture tube, face it in an easterly or westerly direction.
2.Switch on the set’s power and degauss with the degausser.
3-1. Beam Landing
1.Input an all white signal from the pattern generator. Set the Contrast and Brightness to normal.
2.Set the pattern generator raster signal to Red.
3.Move the deflection yoke forward and adjust with the purity control so that the Red is at the centre and the Blue and Green take up equally sized areas on each side of the screen. [See
4.Move the deflection yoke backwards and adjust so that the entire screen becomes Red. [See
5.Switch the raster signal to Blue, then to Green and verify the condition.
6.When the position of the deflection yoke has been determined, fasten the deflection yoke with the screws.
7.If the beam does not land correctly in all the corners, use a magnet to correct it. [See
Fig.
Purity
Fig.
GREEN
RED
BLUE
Fig.
Purity control corrects this area
ab
cd
Deflection yoke positioning corrects these areas
Disk magnets or rotatable disk magnets correct these areas
Caution : |
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High voltages are present on the Deflection yoke terminals |
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- take care when handling the Deflection yoke whilst carrying |
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out adjustments. | Disk Magnets |
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