Vertical-Tilt Wedge Adjustment; Horizontal-Tilt Wedge Adjustment; Unusual Tilt Case; Improving Crt Corner Purity - Zenith B25A10Z Service Manuallines

VERTICAL-TILT WEDGE ADJUSTMENT

The vertical lines at 6 and 12 o'clock are converged 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

The vertical lines at 3 o'clock and 9 o'clock are converged
by horizontally tilting the yoke and inserting a wedge.
Adjust first at 4 or 8 o'clock, whichever has the larger
space, until the wedge is firmly seated between the CRT
glass and yoke coils. Then, insert the 3rd wedge in the
remaining horizontal tilt position until it is firmly seated
between the CRT glass and yoke coils. Convergence at
3 and 9 o'clock should be maintained during this
operation.
When the 3 wedges are firmly installed and positioned
for acceptable convergence, lock the wedges in place by
applying a 2.5 inches long strip of tape 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 instances where the picture tube
and yoke will require vertical tilt in the opposite (up)
direction to obtain convergence. In such cases, insert
the vertical tilt wedge at the bottom (6 o'clock) position.
Follow through on the horizontal tilt adjustment by using
the 2 and 10 o'clock positions and secure each wedge
with a piece of tape, as described above.
6 Pole Magnets
2 Pole Magnets
4 Pole Magnets
CM151
SERVICE ADJUSTMENTS (continued)
X
Clamp and Screw

IMPROVING CRT CORNER PURITY

CRTs that display corner purity problems even after
following the 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. Fully degauss the CRT before installing
correction magnets.

MODIFICATION

1. Place the magnet on the CRT funnel as shown in the
figure displayed below, in the quadrant exhibiting
impurity.
2. Rotate the magnet in place to the position shown
for best purity.
3. Place a piece of 1/2" by 2" long Fiberglass tape over
the magnet to hold it in place.
4. Degauss the CRT once magnet is in place to insure
that the magnet is not over the internal magnet
shield.
NOTE: 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.
3-5
2" To 3"
MAGNET
CA - SERVICING