NEC MultiSync V720 Service Manual page 30

7. Purity
(1) Receive signal 14(Cross hatch pattern).
(2) The CRT face should be facing east and degauss the entire unit by external degaussing coil.
(3) Make sure the single color purity.
If not, readjust CPC magnet and touch up using correction magnets.
8. Convergence
C : Convergence error of horizontal direction
H
C : Convergence error of vertical direction
V
C : Total direction of Convergence error
S
(Calculate by "
(1) Receive signal 14(Cross hatch pattern).
(2) Measure convergence error., If it is out of spec, adjust static convergence by 4-pole magnets and
6-pole magnets.
A Zone (A circle 232 mm in the center of the CRT face center)
B Zone (Areas outside of zone A within the rectangle of 310 mm
Safety with the list below.
C < 0 .3 5 m m
V
0 .3 5 m m < C
√
C ² + C ² "
H V
A
B
310mm
,
C C : Within 0.35 mm
H V
C : No rule
S
< 0 .4 0 m m C a lc u la te C
V
W ith in 0 .5 0 m m → O K
C
V
232mm
C < 0 .3 5 m m
H
O K
a n d ju d g e
S
27
C
H
×
232 mm)
0 .3 5 m m < C < 0 .4 0 m m
H
C a lc u la te C a n d ju d g e
S
W ith in 0 .5 0 m m → O K
N e e d to to u c h u p