SHARP 21HFV1A
Service Manual

2. PURITY ADJUSTMENT

No. 1

Adjustment point PURITY ADJ.

Adjustment procedure/conditions 1. Receive the GREEN-ONLY signal. Adjust the beam current to ~700 µA . 2. Degauss the CRT enough with the degausing coil. Note: Follow the Job Instruction Sheet to adjust the magnetic field. Vertical Bv: +0.030 mT (0.30 gauss) Horizontal Bh: +0.020 mT (0.20 gauss) (Reference: page 3-6) Maintain the purity magnet at the zero magnetic field and keep the static convergence roughly adjusted. Observe the points a, b,as shown in Fig. 1-1 through the microscope. Adjust the landings to A rank requirement. Orient the raster rotation to 0 eastward. Tighten up the deflection coil screws. Tightening torque: 108 ± 20 N (11 ± 2 kgf) 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 700 µA. Note: Set to service mode by remote controller then press factory process R/C RGB key to change to RGB mono colour mode. For the following colours press R/C RGB(Hex 7E) key to change.

Waveform and others

a

b

3.

30mm

Fig. 1-1

30mm

4.

A

5. 6. 7.

B A=B
Fig. 1-2

Rank "A" (on the right of the CRT)

*

A

GREEN ONLY

BLUE ONLY Signal-colour screen cleared

RED ONLY

B A=B

Fig. 1-3

Rank "A" (on the left of the CRT)
* Press R/C RGB key for 1 second in NORMAL MODE, the colour will change to RGB mono colour mode.

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