Sharp CX68KF5 Service Manual page 10

PURITY ADJUSTMENT
No. Adjustment point Adjustment Condition / Procedure
1 PURITY 1. Receive the GREEN -ONLY signal and set the
ADJUSTMENT beam current to 1.6mA with the contrast
control.
2. Degauss the CRT enough with the degaussing
coil.
Note: Follow the job instruction sheet to adjust
the magnetic field.
*BH = 0
*Bv = refer to the job intructions sheet.
Adjustable magnetic field is shown in page 7.
3. Maintain the purity magnet at the zero
magnetic field and keep the static convergence
roughly adjusted.
With P-Mag, adjust it to the center: rank A.
4. Observe the points a, b, as shown in Fig.4-1
through the microscope. Adjust the landings
to A rank requirement.
5. If the a/b balance is poor, compensate it to the
center "Rank AB".
6. Orient the raster rotation to 0 eastward.
7. Tighten up the deflection coil screws.
Tightening torque : 108 ± 20N (11 ± 2Kgf)
8. Make sure the CRT corners landing meet the
A rank requirements. If not, stick the magnet
sheet to correct it.
Note: Apply the adjustment after aging with the
beam current 1,600 ± 50µA or more for
30 minutes or more.
Note: Select the service mode, and press the
monocolour key of R/C for process, and
the monocolour screen (green) will be
selected.
* For the following colours press R/C RGB key
to change.
GREEN BLUE
ONLY ONLY
Single-colour
screen cleared
* Adjustment for uniformity is change to another
content. Please refer to the following page.
Waveform or others
a b
90 mm
Fig. 4-1
A
B
Fig. 4-2 Rank A (On the right of CRT)
A
B
Fig. 4-3 Rank A (On the left of CRT)
* C o n t i n u o s l y p r e s s t h e
monocolour key a second or
more, and the monocolour mode
will be selected without the
service mode.
Even with TEXT key or "R.G.Cy"
key, it can be directly switched to
RED
each monocolour screen.
ONLY
10-1
UNIFORMITY ADJUSTMENT
No. Adjustment point Adjustment Condition / Procedure
1 Uniformity Before adjustment begin, Horizontal magnetic
adjustment (To field=0G, Vertical magnetic field = Each
perform after destination adjustment magnetic field.
the purity and Make sure degauss it.
convergence
90 mm
adjustment) North Direction Red Uniformity
1. Horizontal mf = Set to monocolour screen Red
and adjust to +0.25G.
2. Pay attention to the edge of CRT, if the landing
is poor, adjust by attaching the compensation
magnet at the back of CRT. Refer to Fig.5.
A=B
South Direction Red Uniformity
1. Horizontal mf = Set to monocolour screen Red
and adjust to -0.25G.
2. Pay attention to the edge of CRT, if the landing
is poor, adjust by attaching the compensation
magnet at the back of CRT.
The same method is applied for adjustment of
monocolour screen Blue for blue uniformity, and
A=B
changing both the magnetic field for north and
south direction.
* During the pasting of compensation magent,
use the crosshatch pattern signal.
Make sure there is no blur or bend lines occur.
If the blur or bend lines are serious, adjust the
location of compensation magnet to make it
better.
Waveform or others
(CRT surface)
Miss landing
(CRT back)
Compensation magnet
Fig.5
10-2