Specifications

7-2
Cat. No. 670 Video Board 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 one horizontal trace across the screen, and adequate vertical
gain (approximately 2
µ
sec/div. horizontal, 1 V/div. vertical). With digital film
threaded and running in the projector, observe the video waveform. (See figure
below).
7.3 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
Figure 7- 1.
The best focus is achieved when the scope has minimum brightness.