SHARP 20GT-16C
Service Manual

PURITY CONVERGENCE ADJUSTMENT

NO. Adjustment part Adjusting procedure conditions Waveform and others

PURITY ADJ. GREEN-ONLY Adjust 1 CONVERGENCE 1. Receive the "Crosshatch Pattern" signal. BGR

beam current to ~ 700 µA. ADJ. 2. Using the remote controller, call NORMAL
R 3. Maintain purity magnet at the zero magadjustment.) Static convergence

2. Degauss CRT enough with the degausing (To be done mode. B

coil. a b G after the purity

4. Observe the points a, b, as shown in Fig. 1-1 colours. Fig. 1-1 A rank requirement. angle in order to superpose the green colour
G

netic field and keep static convergence 1. Turn the 4-pole magnet to a proper opening roughly adjusted. angle in order to superpose the blue and red Fig. a
RGB through microscope. Adjust the landings R 5. Orient raster rotation to 0 eastward. over the blue and red colours.

2. Turn the 6-pole magnet to a proper opening

6. Tighten up the deflection coil screws. B

» Tightening torque: 108N ± 20 N Dynamic convergence

7. Make sure CRT corners landing meet screen in the following steps. Fig. b

(11kgf ± 2 kgf) 1. Adjust convergence on fringes of the A
B

A rank requirements. If not, stick magnet RGB a) Fig. a : Drive the wedge at point "a" and sheet to correct it. B swing the deflection coil upward. G Note:This adjustment must be done after b) Fig. b : Drive the wedge at point "b" and "c" R warming up unit for 30 minutes or and swing the deflection coil downward. longer with a beam current over 700 c) Fig. c : Drive the "c" wedge deeper and
A = B µA.

swing the deflection coil rightward. Fig. 1-2
R G

* For following colours press R/C RGB key to d) d : Drive the "b" wedge deeper and Fig. c
(on right of the CRT)

change. Rank "A" swing the deflection coil leftward. BGR 3. Apply lacquer to the deflection yoke lock screw,
A

2. Fix all wedges on the CRT and apply glass tape over them. B magnet unit (purity, 4-pole, 6-pole magnets) and magnet unit lock screw. Fig. d Green-only Blue-only Red-only

7
B on the screen.

Finally received the Red-only and Blue-only signals to make sure there is no other colours Wedge "a"
screen cleared
A = B

Signal-colour About 100°

4-pole magnet 6-pole magnet CRT neck Fig. 1-3

Lacquer

(on left of the CRT) Wedge

Rank "A"
"b" "c"

* Press R/C RGB key for 1 second in NORMAL MODE, the colLacquer our will change to RGB mono Purity magnet colour mode.

20mm

21GT-22

7-1 7-2