Lens Focus Adjustment - Hitachi C47-WD7000 Service Manual

SERVICE ADJUSTMENTS

2.11 LENS FOCUS ADJUSTMENT

Adjustment preparation
(1) The orientation of PTV set is arbitrary, west, east, north and south.
(2) Centering DY tilt should be adjusted.
(3)Electrical focus adjustment should have been completed.
(4)Drive VR location adjustment should have been completed.
(5) Red : 12 0'clok, Green : 1~2 0'clock)
(6) Receive the NTSC cross-hatch signal.
(7) Contrast control should be set Center and Brightness control should be set minimum.
Adjustment procedure
(1) Loosen the fixing screw or wing nut on the lens cylinder so that the lens cylinder can be turned.
(Be careful not to loosen too much)
After completing steps (4), (5), (6) below, tighten the fixing screws or wing nuts for each lens with a torque of
0.67N.m(7Kgf cm) ~ 1.18N.m(12Kgf cm).
(Do not turn the lens cylinder after having a screw and wing nuts tightened. Also do not tighten the screw too
much, otherwise the lens will be tilted too much or the screw will be broken).
Lens sass
(2) Apply covers to each colors of R, G and B lenses. and project a single color beam on the screen and adjust in
sequence. (The adjustment order of R, G and B is only an example.)
(3) If the lens adjustment knob is tuned clockwise viewed from the front, the color aberration change as follows.
Cross-Hatch
RED LENS
GREEN LENS
BLUE LENS
(NOTE1)
Fixing screw
TYPE 1
Short focus
Lens sass
Color aberration
Change of color aberration
Orange
Blue
Purple
39
(NOTE2)
Fixing Wing nuts
TYPE 2
Long focus
Scarlet
Red
Green