Purity And Convergence Procedure - Panasonic CT-27C8G Service Manual

11 Purity and convergence procedure
Adjustment is necessary only if the CRT or the deflection yoke Slide the deflection yoke back and forth on the neck of the
is replaced or if the setting was disturbed. The complete CRT until it produces a near white, uniform raster.
procedure consists of: VERTICAL RASTER SHIFT ADJUSTMENT
1. Vertical raster shift adjustment. Apply a green pattern with a horizontal line, adjust the
2. Initial static convergence. Deflection Yoke so that has no tilt, then secure it.
3. Setting the purity. Adjust center line of the pattern with the mechanical center
4. Final static convergence. of the CRT, this center is determined by two marks at the
side edges of the screen. To adjust the line, once the
vertical raster shift tabs are place at 3 o'clock to reduce its
magnetic field effect open the tabs the same angle from the
WHEN THE CRT OR THE YOKE IS REPLACED
For 2 piece assembly:
Position purity/convergence assembly as shown and center, until the center line of the pattern becomes a
tighten clamp snugly. Remove the hot-melt glue seal on straight line, centered with the marks of the CRT.
assembly and position like tabs of purity device together IMPORTANT NOTICE
at 12 о" clock to reduce its magnetic field effect. : | : : :
Rings come along with deflection yoke in one piece.
Open the
same angle
from center
Vertical raster shift tabs
R&B Convergence Ring Purity Rings Centered
R&B&G Convergence Е 5 Му Over G3/G4 Gap
= | (| es | ва
АШ
2 piece assembly
For models using 4 pairs of rings, place the yoke on the
CRT neck (do not tighten the clamp). Place the vertical
raster shift tabs at 3 o'clock (90% from the purity and
Vertical raster shift adjustment
convergence tabs.
INITIAL CENTER STATIC CONVERGENCE
- Connect a dot/cross hatch generator to the receiver and
наваб Convergence Ringe A
Hal di о"
tune in a signal. Observe misconvergence at center of the
screen only.
Adjust the R&B pole magnets; by separating tabs and
rotating to converge blue with red.
Adjust the R&B and R&B&G pole magnets: by separating
tabs and rotating to converge blue and red (magenta) with
green.
NOTE
Precise convergence at this point is not important.
PURITY ADJUSTMENT
When the receiver is in the serviceman mode for making
electronic adjustments, press the RECALL button on the
remote control to enter purity check. (See the service
adjustments electronic controls procedure).
Vertical Raster Shift Ring ЈА
Description of rings
R&B&G Convergence Rings 90°. - >
&— R&B Convergence Rings * г
У
Vertical Raster 79
Shift Rings
w Purity Rings "d
Operate the receiver for 60 minutes using the first purity
check field (white screen) to stabilize the CRT.
Fully degauss the receiver by using an external degaussing
Coil.
Press the RECALL button on the remote control again until
the purity check (green screen) appears.
Initial position of rings Loosen the deflection yoke clamp screw and move the
Turn the receiver ON. Operate the receiver for 60 minutes 22 yoke back as close to the purity magnet as
possible.
using the first purity check field (white screen) to stabilize
the CRT. Adjust the purity rings to set the vertical green raster
Fully degauss the receiver by using an external degaussing precisely at the center of the screen.
coil.
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