Convergence; Measuring Conditions; Convergence Measuring Gauge; Static Convergence - Nokia 445PRO Service Manual

7.7. Convergence

Reduce first the convergence error in the middle of the screen to minimum using static adjustments.
After the convergence is faultless in the middle of the tube, use dynamic adjustments to eliminate
the error in the edges of the tube.
Static adjustments affects the whole picture area:
-- Magnet ring set on the tube neck (horizontal + vertical)
Dynamic adjustments affects a part of the picture area:
-- Deflection yoke trimmers.

7.7.1. Measuring Conditions

Adjust convergence with 107.10/85.0 (NCE791) line frequency.
--
Make sure that focus is correctly set at the mid-point between the screen center and the edge of
--
the picture.
Use white crosshatch test pattern with circle.
--
Adjust to near the maximum and reduce
--
7.7.2. Convergence Measuring Gauge CM7AR
The use of the Klein CM7AR Convergence Gauge has been explained here but other types of
gauges can be used as well.
Check that the adjusting knobs (A & B) are set to zero.
- - Place the gauge on the line with marking Y up upwards when measuring horizontal line.
- - Place the gauge on the line with marking X up upwards when measuring vertical line.
- - If the line has convergence error, the line in the window seems to be broken.
- - Use knobs A and B to adjust the line continuous.
- - If the readings are on the opposite side of zero, the convergence error is A+B (e.g. 0.2 + 0.1
= 0.3).
- - If the readings are on the same side of zero, the convergence error is equal to A if A > B or
B if B > A

7.7.3. Static Convergence

The magnet rings has been set to the optimum in the factory. Readjustment is necessary only in
case the adjusting magnets have been accidentally moved.
Adjust G vertically in the middle between R and B with 6 pole magnet rings.
1
Adjust G horizontally in the middle between R and B with 6 pole magnet rings.
2
Adjust R and B vertically to the same position with G line with 4 pole magnet rings.
3
Adjust R and B horizontally to the same position with G line with 4 pole magnet rings.
4
Lock the rings with paint.
3
1
G
R
4
2
Rotating both rings together
1 3
B
until the background disappears.
B
Y
A
4 pole magnet rings
6 pole magnet rings
SMH
Sliding two ring tobs toward
or away from each other
2 4
445N
X
0.5 0
0.5 0 0.5
Blue
Red
Green
Purity magnet rings.
Do not adjust !
3 4
1 2
0.5
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