3-2
6.
Adjust the Ch 2 vertical trace position to move the trace off the screen. It is not
necessary to view this signal once triggering has been established.
Cat. No.670 Video Board (DA20 slot 12) Test Points:
VIDEO
TP1 (white)
The CCD video signal
VGND
TP2 (black)
Ground reference for Video signal
CLAMP
TP3 (green)
Horizontal Sync. to view Video scan.
TRACK
TP4 (brown)
Perforation rate - check for 96Hz
+15
TP5 (yellow)
+15V power supply rail
+5
TP6 (red)
+5V power supply rail
DGND
TP7 (black)
Digital ground reference
–15
TP8 (blue)
–15V power supply rail
Adjust the scope for 1 horizontal trace across the screen, and adequate vertical gain
(approx. 2 sec/div. horizontal, 1 V/div. vertical). With a Dolby Digital film threaded and
running in the projector, observe the video waveform. (see figure in Section 3.3).
3.3
Focus Adjustment
Cat. No.700 Digital Soundheads are factory adjusted and should not require adjustment
during installation. If the soundhead has become misadjusted, focusing may be
performed. Using the setup as above, adjust the objective lens/CCD assembly in the
reader head by loosening the 2mm hex socket set screw (located below the lens bore)
which holds the lens/CCD assembly in place, and moving the assembly back and forth.
There are two methods for moving the assembly. A flat blade screw driver inserted in the
oval slot above the lens can be twisted to slide the assembly. Alternately, if the CCD
circuit board cover is removed, the assembly can be moved back and forth with the
thumb and forefinger. The best focus is achieved when the scope pattern has minimum
brightness in the center of the trace. There will always be some light here; one is looking
for the most “focused looking” display, with minimum brightness inside the envelope.
This should correlate with minimum error rate. Re-tighten the lens holding screw.
Adjust for minimum brightness in center of image.
2.7 to 5 volts
