JVC DT-V1710CG Service Manual page 62

HORIZONTAL/VERTICAL IMAGE POSITION, IMAGE AMPLITUDE AND IMAGE DISTORTION ADJUSTMENTS (NTSC/PAL UNDERSCAN 4:3 MODE)
Measuring Instruments
Card (Slot)
Test Points
Adjustment Points
Note:
•
Perform the following adjustments after completing
the Reference Mode (NTSL/PAL overscan 4:3 mode)
adjustments.
(1) Apply the NTSC mono-scope signal to INPUT C (Terminal
VIDEO1 on the NTSC/PAL Video Input Card).
(2) Set the CONTRAST and BRIGHT potentiometers on the
front panel to the center click positions.
(3) Press the UNDER SCAN button on the front panel to set
the scanning size to underscanning.
(4) Adjust DB04 in the Service Menu to set the vertical position
of the image at the center of the CRT screen.
(5) Adjust DB02 to set the vertical amplitude of the image to
233mm.
(6) Apply the NTSC crosshatch signal to INPUT C.
(7) Adjust DB11 to set the sizes of the rectangles at the center
of the image and those at the left and right ends to be
identical.
(8) Adjust DB12 to set the sizes of the rectangles at the center
of the image and those at the top and bottom to be identical.
(9) Ensure that the center position is not deviated. If it is, adjust
DB04 again.
(10) Adjust DB11, DB12 and DB04 repeatedly until the center
position and vertical linearity are optimized.
(11) Adjust DB09 to optimize the trapezoidal distortion (observe
the second vertical lines from the left and right edges as the
reference).
(12) Adjust DB08 to optimize the parallelogram distortion
(observe the second vertical lines from the left and right
edges as the reference).
(13) Adjust DB10 to optimize the horizontal arc distortion.
(14) Adjust DB05 so that the second vertical lines from the left
and right edges are linear.
(15) If there is an extreme corner S-shape distortion, adjust DB07
to optimize it (this adjustment is usually unnecessary).
(16) If there is an extreme corner W-shape distortion, adjust DB06
to optimize it (this adjustment is usually unnecessary).
(17) Apply the NTSC mono-scope signal to INPUT C.
(18) Ensure that the vertical amplitude of the image is 233mm. If
it is not, adjust DB02 again.
(19) Adjust DB03 so that the horizontal position of the image
comes at the center of the CRT screen.
(20) Adjust DB01 to set the horizontal amplitude of the image to
311mm.
(21) Vary the adjustment signal and adjustment data, and re-
perform adjustments in steps 1 to 20 above (see Table 15).
1-62 (No. 52152)
Signal generator (Mono-scope signal, Crosshatch signal)
NTSC/PAL Video Input Card (Slot 2)
D*01 (Horizontal Size), D*02 (Vertical Size), D*03 (Horizontal Position), D*04 (Vertical Position),
D*05 (Side Pin Distortion), D*06 (Corner Distortion (W)), D*07 (Corner Distortion (S)), D*08
(Parallelogram Distortion), D*09 (Trapezoidal Distortion), D*10 (Horizontal Arc Distortion), D*11
(Vertical Linearity (S Correction)), D*12
(Vertical Linearity (C Correction)) [Service Menu]
Screen size
Scanning size (100%)
90 80
311mm
Make these lines linear.
Adjustment Adjustment
Step No. signal
1 NTSC
2 PAL
Table 15
90
80
80 90
233mm
Adjustment
Data
DB
DD