- 18 -
•
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
.................................. normal
Brightness .................................. normal
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 TV set’s power and degauss with a degausser.
(1) Adjustment of Correction Magnet for Y-Splitting Axis.
1.
Input a crosshatch signal from the pattern generator.
2.
Set the Picture control to minimum and confirm that the
Brightness control is set to normal.
3.
Position the neck assembly as indicated in Fig.3-2.
4.
Loosen the deflection yoke fixing screw.
5.
Move the deflection yoke as far forward as is possible.
6.
Adjust the upper and lower pin symmetrically by opening or
closing the Y-splitting axis correction magnets located on the
neck assembly. [See Fig 3-3]
7.
Return the deflection yoke to its original position and re-tighten
its fixing screw.
Carry out the adjustments in the following order :
3-1.
Beam Landing.
3-2.
Convergence.
3-3.
Focus.
3-4.
White Balance.
Note : Test equipment required.
1.
Color bar/pattern generator.
2.
Degausser.
3.
Oscilloscope.
4.
Digital multimeter.
Fig.3-1
(2) Landing
Note : Before carrying out the following adjustments adjust the
magnets as indicated [See Fig.3-4].
1.
Input a crosshatch signal from the signal generator.
2.
Rough-adjust the focus and horizontal convergence.
3.
Switch from the crosshatch pattern to an all-red pattern.
4.
Move the deflection yoke backwards and adjust with the purity
magnet so that the red is at the centre and it aligns
symmetrically [See Fig.3-5].
5.
Move the deflection yoke forward to the point where the entire
screen just becomes red [Mark its position].
6.
Move the deflection yoke further forward until the screen just
changes colour at the edges. [Mark its position]
7.
Position the deflection yoke between the two marks indicated
above.
8.
Input a crosshatch pattern from the pattern generator and rotate
the deflection yoke so that the horizontal lines are parallel with
the top and bottom of the screen.
9.
When the position of the deflection yoke has been determined,
fasten it with its fixing screw.
10. Switch the pattern generator to green then blue and confirm the
purity.
11. If the beam does not land correctly in all the corners of the
screen, use disk magnets to correct it. [Confirm the corner
landing forgreen and blue]
Caution :
High voltages are present on the Deflection yoke terminals - take care
when handling the Deflection yoke whilst carrying out
adjustments.
Y-splitting axis correction magnet
Fig.3-3
Fig.3-2
Neck assy
Align the edge
of the neck assy with
the edge of the G2 grid
on the G3 side.
G2
G1
G3
+
SECTION 3 SET-UP ADJUSTMENTS
3-1. Beam Landing
