JVC AV-56WP30, Service Manual

Page: 34 / 122

No. 52007
AV-56WP30
34
FOCUS & BEAM SPOT ADJUSTMENT
Item
Measuring
instrument
Test point Ad justment part Description
FOCUS &
BEAM SPOT
adjustment Signal
generator
Similar
adhesive
(Securing
adhesive)
G Def. Yoke (DY)
R Def. Yoke (DY)
B Def. Yoke (DY)
[Projection unit]
R LENS FOCUS
screw
G LENS FOCUS
screw
B LENS FOCUS
screw
[Projection unit
(LENS ASS’Y)]
R SCREEN VR
G SCREEN VR
B SCREEN VR
[FOCUS PACK]
4 pole magn et
2 pole magn et
[Projection unit
(CRT neck)]
R FOCUS VR
G FOCUS VR
B FOCUS VR
[FOCUS PACK]
1. Receive a cross-hatch signal.
2. Press the ASPECT and select the FULL mode.
3. If the picture tilted, adjust the R, G and B DY position to mark
straight horizontal line.
!
LENS FOCUS
4. Makes a red single color.
NOTE : W hen mak ing a single color, It squeezes SCREEN VR in
each one, or it does a lid to the lens in of the adjustment
color and it makes it single color.
5. By turning the LENS FOCUS screw (in LENS ASS’Y), for
optimum focus at the screen center. Chec k for absence of
differenc e in the peripheral focus. If the peripheral focus is
poor, slightly s hift the c enter foc us to obtain overall balanced
foc us.
6. In the same manner, produce green and blue single color and
adjust their respective focus.
7. After adjustment, it fixes a screw.
NOTE : There is not a difference in the focus in the top and the
bottom, on either side, in the diagonal.
When the difference of the focus is big, it removes a main
lens, and it puts a washer between the main lens and the
coupler and it adjusts it.
!
BEAM SPOT
8. Receive a dot pattern signal.
9. Makes a red single color.
NOTE : W hen mak ing a single color, It squeezes SCREEN VR in
each one, or it does a lid to the lens in of the adjustment
color and it makes it single color.
10. Turn the R FOCUS VR to set the dot diameter to about
φ
30mm.
11. Turn the 4 pole magnet of the projection unit CRT neck and to
where the dots at the screen center are nearly circular.
12. Return the R FOCUS VR to its original position (just focus).
13. Turn the 2 pole magnet of the CRT nec k to minimize expansion
of the dots.
14. In the s ame manner, adjust for the green and blue single color
foc us.
15. Secure the 4 and 2 pole magnets with similar adhesive.
! CRT FOCUS
16. Receive a cross hatch signal.
17. Makes a red single color.
NOTE : W hen mak ing a single color, It squeezes SCREEN VR in
each one, or it does a lid to the lens in of the adjustment
color and it makes it single color.
18. Adjust the R FOCUS VR for optimum focus at the position
indic ated in the figure.
19. In the s ame manner, adjust for the green and blue single color
foc us.
20. After adjustment, return the SCREEN VRs to their original
positions.
NOTE : When moving screen VR, always return to original.
CRT FOCUS adjustment point
PROJECTION UNIT & LENS ASS’Y
(CRT adjustment location)
LENS FOCUS
SCREW
CENTERING
MAGNET
4 POLE
MAGNET
2 POLE
MAGNET
DEFLECTION
YOKE