Sharp 14GT15, Service Manual

Page: 12 / 54

12
14GT15
14GT20
PURITY ADJUSTMENT
No. Adjusting point Adjusting procedure/conditions Waveform and others
PURITY ADJ. 1. Receive the GREEN-ONLY signal. Adjust the
beam current to about 500
µ
A.
2. Maintain the purity magnet at the zero magnetic
field and keep the static convergence roughly
adjusted.
3. Observe the points a, b as shown in Fig. 4-1
through the microscope. Adjust the landing to the
A rank requirements.
4. Orient the raster rotation to 0 eastward.
5. Tighten up the deflection coil screws.
»
Tightening torque: 108
±
20 N (11
±
2 kgf)
6. Make sure the CRT corners landing meet the A
rank requirements. If not, stick the magnet sheet
to correct it.
Note: This adjustment must be done after
warming up the unit for 30 minutes or
longer with a beam current over 500
µ
A.
1
a
b
A
B
A
B
A = B
A = B
Rank "A"
(on the right of the CRT)
Rank "A"
(on the left of the CRT)
Fig. 4-1
Fig. 4-2
Fig. 4-3