Convergence Adjustment - Sharp 21F-PA18 Service Manual

3. CONVERGENCE ADJUSTMENT

No. Adjustment point
1 CONVERGENCE
ADJ.
( To be done
after the purity
adjustment.)
(No need if used
ITC CRT)
Adjustment procedure/conditions
1. Receive the "Crosshatch Pattern" signal.
2. Using the remote controller, call NORMAL mode.
Static convergence
1. Turn the 4-pole magnet to a proper opening an-
gle in order to superpose the blue and red col-
ours.
2. Turn the 6-pole magnet to a proper opening an-
gle in order to superpose the green colour over
the blue and red colours.
Dynamic convergence
1. Adjust the convergence on the fringes of the
screen in the following steps.
a) Fig. a: Drive the wedge at point "a" and swing
the deflection coil upward.
b) Fig. b: Drive the wedge at point "b" and "c" and
swing the deflection coil downward.
c) Fig. c: Drive the "c" wedge deeper and swing
the deflection coil rightward.
d) Fig. d: Drive the "b" wedge deeper and swing
the deflection coil leftward.
2. Fix all the wedges on the CRT and apply glass
tape over them.
3. Apply lacquer to the deflection yoke lock screw,
magnet unit (purity, 4-pole, 6-pole magnets) and
magnet unit lock screw.
Finally received the Red-only and Blue-only sig-
nals to make sure there is no other colours on the
screen.
4-pole magnet
Lacquer
Purity magnet
21F-PD250 / 21F-PT220 / 21F-PA18 / 21F-PA18(B)
6-pole magnet
CRT neck
20mm
3 – 16
Waveform and others
BGR
Fig. a
RGB
Fig. b
RGB
B
G
R
Fig. c
BGR
R
G
B
Fig. d
Wedge "a"
About
100Deg
Lacquer
Wedge
"b"
B
G
R
R
G
B
About
100Deg
Wedge
"c"