Horizontal - Tilt Wedge Adjustment; Improving Crt Corner Purity; Unusual Tilt Case - Hitachi 27CX22B 501 Service Manual

SERVICING
VERTICAL-TILT - WEDGE ADJUSTMENT
Converge the vertical lines at 6 and 12 o'clock by
vertically tilting the yoke and inserting a wedge at the top
of the yoke until it is firmly seated between the CRT glass
and the horizontal coils.
HORIZONTAL - TILT WEDGE ADJUSTMENT
Converge the vertical line at 3 o'clock and 9 o'clock by
horizontally tilting the yoke and inserting a wedge.
First, at 4 or 8 o'clock, whichever has a larger space,
insert a second wedge until it is firmly seated between the
CRT glass and yoke coils. Then insert the third wedge in
the remaining horizontal tilt position until firmly seated
between the CRT glass and yoke coils. Convergence at 3
and 9 o'clock should be maintained during this operation.
When the three wedges are firmly installed for acceptable
convergence, lock the wedges in place by applying a strip
of tape (2.5" long) across the tabs of each wedge, firmly
against the CRT glass. The CRT glass surface should be
clean and free of dust and other foreign material,
UNUSUAL TILT CASE
There may be some cases of picture tube and yoke that
require vertical tilt in the opposite (or up) direction to
obtain convergence. In such cases, insert the vertical tilt
wedge at the bottom (or 6 o'clock) position. Follow
through the horizontal tilt adjustment by using the 2 and
10 o'clock position and secure each wedge with a piece of
tape as described above.
TT
LClamp and Screw
L-
I6 Pole Magnets
2 Pole Magnets
-4 Pole Magnets
IMPROVING CRT CORNER PURITY
CRTs that display corner purity problems even after
following service procedures can be modified with a
picture correction kit (P/N 949-50). The purity can be
improved by placing a picture correction magnet
(included in the kit) on the CRT funnel. Refer to the
following modification steps and illustration to place the
magnet properly.
MODIFICATION
1. Place the magnet on the CRT funnel (as shown) in the
quadrant exhibiting impurity.
2. Rotate the magnet in place to the position shown for
best purity.
3. Place a piece of l/2" x 2" Fiberglass tape over the
magnet to hold it in place.
4. Degauss the CRT once the magnet is in place to insure
that the magnet is not over the internal magnet shield.
If the magnet is placed over the internal magnet shield,
any apparent purity correction will disappear after
degaussing. Reposition the correction magnet off the
internal shield and degauss again.
To 3"
9