Memorex MVT2137, Service Manual

Page: 36 / 72

ELECTRICAL ADJUSTMENTS
3. PURITY AND CONVERGENCE
ADJUSTMENTS
NOTE
1.
2.
3.
Turn the unit on and let it warm up for at least 30
minutes before performing the following adjustments.
Place the CRT surface facing east or west to reduce the
terrestrial magnetism.
Turn ON the unit and demagnetize with a Degauss Coil.
3-1: STATIC CONVERGENCE (ROUGH ADJUSTMENT)
1.
2.
3.
4.
5.
6.
7.
8.
Tighten the screw for the magnet. Refer to the adjusted
CRT for the position. (Refer to Fig. 3-1)
If the deflection yoke and magnet are in one body,
untighten the screw for the body.
Receive the green raster pattern from the color bar
generator.
Slide the deflection yoke until it touches the funnelside
of the CRT.
Adjust center of screen to green, with red and blue on
the sides, using the pair of purity magnets.
Switch the color bar generator from the green raster
pattern to the crosshatch pattern.
Combine red and blue of the 3 color crosshatch pattern
on the center of the screen by adjusting the pair of 4
pole magnets.
Combine red/blue (magenta) and green by adjusting the
pair of 6 pole magnets.
Adjust the crosshatch pattern to change to white by
repeating steps 6 and 7.
3-2: PURITY
NOTE
Adjust after performing adjustments in section 3-1.
1.
2.
3.
4.
5.
Receive the green raster pattern from the color bar
generator.
Adjust the pair of purity magnets to center the color on
the screen.
Adjust the pair of purity magnets so the color at the
ends are equally wide.
Move the deflection yoke backward (to neck side)
slowly, and stop it at the position when the whole screen
is green.
Confirm red and blue colors.
Adjust the slant of the deflection yoke while watching
the screen, then tighten the fixing screw.
DEFLECTION YOKE
DEFLECTION YOKE SCREW
MAGNET SCREW
6 POLE MAGNETS
4 POLE MAGNETS
PURITY MAGNETS
Fig. 3-1
3-3: STATIC CONVERGENCE
NOTE
Adjust after performing adjustments in section 3-2.
1.
2.
3.
Receive the crosshatch pattern from the color bar
generator.
Combine red and blue of the 3 color crosshatch pattern
on the center of the screen by adjusting the pair of 4
pole magnets.
Combine red/blue (magenta) and green by adjusting the
pair of 6 pole magnets.
3-4: DYNAMIC CONVERGENCE
NOTE
Adjust after performing adjustments in section 3-3.
1.
2.
Adjust the differences around the screen by movingthe
deflection yoke upward/downward and right/left.
(Refer to Fig. 3-2-a)
Insert three wedges between the deflection yoke and
CRT funnel to fix the deflection yoke.
(Refer to Fig. 3-2-b)
R G B
R
G
B
R G B
R
G
B
RIGHT/LEFT SLANT UPWARD/DOWNWARD SLANT
Fig. 3-2-a
WEDGE
WEDGE
WEDGE
WEDGE POSITION
Fig. 3-2-b
D3-5