JVC AV-48WP34/AHA Service Manual page 40

AV-48WP30
FOCUS & BEAM SPOT ADJUSTMENT
Measuring
Item
instrument
FOCUS & Signal
BEAM SPOT generator
adjustment
Similar
adhesive
(Securing
adhesive)
DEFLECTION
YOKE
LENS FOCUS
SCREW
4 POLE
MAGNET
PROJECTION UNIT & LENS ASS'Y
( CRT adjustment location )
CRT FOCUS adjustment point
34
Test point Adjustment part
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 magnet
2 pole magnet
CENTERING
[Projection unit
MAGNET
(CRT neck)]
R FOCUS VR
G FOCUS VR
B FOCUS VR
[FOCUS PACK]
2 POLE
MAGNET
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 : When making 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. Check for absence of
difference in the peripheral focus. If the peripheral focus is
poor, slightly shift the center focus to obtain overall balanced
focus.
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 : When making 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 neck to minimize expansion
of the dots.
14. Receive a crosshatch signal.
15. Adjust the overall screen focus.
16. In the same manner, adjust for the green and blue single color.
focus.
17. Secure the 4 and 2 pole magnets with similar adhesive.
! CRT FOCUS
18. Receive a crosshatch signal.
19. Makes a red single color.
NOTE : When making 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.
20. Adjust the R FOCUS VR for optimum focus at the position
indicated in the figure.
21. In the same manner, adjust for the green and blue single color
focus.
22. After adjustment, return the SCREEN VRs to their original
positions.
NOTE : When moving screen VR, always return to original.
No. 51914
Description