Component Engineering STRD-30S User manual

Copyright ©Component Engineering, All Rights Reserved
STRD-30S
Digital /Analog Sound Reader
for Simplex Projectors

1
STRD-30S
Analog and digital sound pre-amps
Digital/Analog Sound Reader for Simplex Projectors
Installation Instructions
The following installation instructions assume that all
conventional sound track reading elements have been removed
from the sound head. These include the exciter lamp and its
socket assembly, the slit lens with its mounting bracket, and the
entire photocell assembly. The sound drum (rotary stabilizer) and
its ball bearings must also be removed temporarily.
NOTE: The analog and digital sound pre-amps and their optics
are shipped already installed in the dual lens mount. This
assembly has been pre-aligned in a standard Simplex 5 Star
sound head. You are strongly urged to leave it as a unit so that
when you are ready to do the final alignment of the sound head,
focus and azimuth will be very close to their final positions.

2
Position the locator plate
Install the adaptor block
Optical pieces properly aligned
As you begin the installation please refer to the drawings on the
left. The first part to install is the locator plate. This is a 3/16"
(4.7mm) thick flat aluminum piece in which there is a large
hole....just the size of the drum shaft ball bearings. Attached to
the plate is a standoff post used to support the LED assembly
Position the locator plate’s large hole over the sound drum’s
ball bearing seat and hold in place with three 8-32 X 1/2" screws
through the holes on the right side of the plate.
Do not tighten these screws.
This is a good time to also loosely install the adapter block.
Look at the locator plate you just put in, and in the tongue-like
piece on the left you will see two holes into which the dowels
from the adapter block are to be inserted. They are supposed to
be snug, so you may have to proceed slowly. The four mounting
holes in the adapter block will now be over the tapped holes
originally used to mount the slit lens holder in the casting. Install
the four 8-32 X 1/2" screws but do not tighten.
The reason for all this loose mounting is so that we can get all of
the optical pieces properly aligned exactly on radius with
reference to the center line of the sound drum. You are going to
use the outboard sound drum bearing to accurately position the
locator plate, and then all the other parts will automatically be
aligned. You can do this either with a loose bearing, or, as is
usually the case, with the bearing still on the shaft. The idea is to
slide the bearing through the large hole in the locator plate and
part way into the bearing seat. With the bearing partly in the plate
and partly in the bearing seat, the plate will be positioned exactly
on center with respect to the sound drum. Now you can tighten
the three screws which hold the plate, the four screws in the
adapter block, and finish reinstalling the sound drum and
flywheel.

3
LED assembly
Dual lens/pre-amp assembly
Rear of the LED assembly
The LED assembly can now be mounted to the top of the
standoff post by means of three 4-40 Flat Head screws. The
Lateral Guide can also be reinstalled.
The dual lens/pre-amp assembly should now be carefully eased
onto the dowel pins in the adapter block and bolted in place. It is
a good idea to have the digital video cable already plugged onto
the digital pre-amp circuit board before you mount this assembly.
Wiring
Connect both of the LED’s to the outputs of the LS-30 power
supply chassis. The small terminal strips at the rear of the LED
assembly can be unplugged by pushing away from you. Note that
no polarity is indicated. This is because the LED’s may come
with either polarity and you will have to determine the correct
connection by trial and error. It is safe to do this because the
output of the LS-30 power supplies is clamped at a voltage too
low to damage the LED’s. The recommended wire size is #18
AWG.

4
Analog pre-amp
The analog pre-amp is powered by the 12 Volt bipolar supply in
the LS-30 and three conductor 22 Gauge wire is perfectly
adequate for this purpose.
The analog audio output from the pre-amp should be two
shielded pairs, one for each channel. They can be individual
cables, or two pairs in one jacket. Normal audio wire such as you
would use for any other purpose is ideal.
All of the terminal strips on the analog pre-amp can be unplugged
at the pre-amp.
The video output cable from the digital pre-amp in the sound
head to the Dolby DA-10 or DA-20 is harder to deal with because
it is so stiff and heavy. The cables are shipped with both ends
terminated in their respective connectors. The smaller connector
(the sound head end) can be gotten through 3/4" conduit, but care
must be taken if there are many bends and particularly when
going through any conduit fittings. The connector is polarized
and will plug onto the video pre-amp only one way.
Digital pre-amp

5
Adjustment of the two light sources
Adjust the analog LED
Alignment
Preliminary:
Because you are dealing with two soundtracks, and because you
are starting from scratch, you will have to go back and forth
between the two media while you get everything optimized.
Mostly, this means the adjustment of the two light sources.
The good news is that as already mentioned, the two optical
assemblies have been preset so that you have a beginning point.
Their focus and azimuth may not be exactly correct for your
sound head, but they will be close enough to get you started.
Loosen the clamp screw of both of the copper LED mounts until
they can be moved easily, but will stay where you put them when
you let go. It is easier to grab both of the mounts when doing the
analog LED (which is the inner one), and so it is best to do it
first.
Analog:
Adjust the analog LED by eye until it looks as though it is
opposite the lower lens. In the cinema processor, turn both the
level and high frequency adjustments all the way down so that
both channels will be essentially identical. Thread a loop of
Dolby Cat. No. 97 (a very convenient method is to make a loop
of 1/2 Cat. No. 97, and 1/2 “Buzz Track”) and look at it on your
oscilloscope just as you would for a normal “A” Chain setup.

6
Adjust the lateral guide roller
Analog focus and azimuth alignment
Adjust the lateral guide roller until you have agreement
between both the Cat. No. 97 and the “Buzz Track”. Adjust the
lateral position of the LED for maximum output from both
channels. The lateral guide position is important because it also
establishes the correct position for reading the digital track.
Move the LED in and out and vertically (rotationally) until you
have achieved the maximum output from both channels. Gently
tighten the clamp screw of the analog mount. Try not to overdo
the screw tightening so that the threads in the soft copper are not
deformed. There is a large area of contact between the copper
mount and the round stud on the support plate which means that
it takes only modest clamping pressure to firmly hold the
adjustment. (The other reason for this large contact area is that
there is very good heat transfer from the LED itself right on down
to the base casting of the sound head. This means extra long life
for the LED.)
Now is the time to do the rest of the analog focus and azimuth
alignment procedures. Before you do your final Dolby Tone
level adjustment, it is a good idea to run Dolby Cat. No.566
scanning beam illumination film. Touch up the in-and-out
adjustment of the LED if necessary. If you are sure that your
vertical, or rotational, adjustment is nearly correct, there is an
interesting method of optimizing it. Remove all film from the
projector and turn on the motor. Monitor the sound from the
reader and turn the gain up until you hear the slight microphonics
from the running projector. Tweak ever so carefully the vertical
position of the LED until the least sound is heard. This will be the
optimum position of the LED Lock the clamp screw, set your
Dolby Tone level and move on to the digital.

7
Screen snapshot of DRAS 10 software reading a loop of Dolby Digital test film
(note the recurring splice Error History).
Digital:
Connect your ’scope to Dolby’s digital processor (DA-10, DA-20, or CP500) according to their instructions, and start
running some digital film. The following are optional but highly recommended: A 486 class or better computer having a
high-speed (115kbs.) serial port and DRAS-10 software from Dolby. A nine conductor male to female cable with standard
9 pin “D” connectors that are wired pin to pin. It is possible to perform a good alignment using test film and an
oscilloscope, or it is possible to use test film and a computer running Dolby's DRAS-10 software.

8
Adjust the digital LED
Best of all, however, is to use both at the same time. The ’scope
will show you the real-time video of what the reader is “seeing”
on the soundtrack, while the computer will numerically display,
focus, azimuth, vertical jitter, lateral alignment and more. Taken
all together, proper alignment is quick, easy, and accurate. (If you
are running loops, try to make them fairly long so that the splice
doesn’t come around too often). The digital reader optics should
be close enough for you to find a ‘scope picture similar to this
illustration.
The first thing is to adjust the digital LED.You want the
brightest and most even light you can get. This will be indicated
on the ’scope screen by the flattest trace with the greatest
amplitude. Now that you have adjusted the analog LED, you
know the routine except that this time you will be working with
the outer LED only. Be careful not to loosen the analog LED
mount so that you won’t have to do all that work over again. A
large saw tooth surface in the trace means you must fine adjust
the rotational alignment of the LED.

9
CCD board lateral adjustment
Adjust focus and azimuth of digital optics
Loosen the CCD board lateral adjustment locking screws and
adjust the lateral position so that outer trace (perf) is off center by
1/5 major graticule to the left between goal posts. A correct
DRAS “lateral position” read out should be as close to zero as
possible. As you retighten the screws be careful not to walk the
board in the reader.
We are ready to adjust the focus and azimuth of the digital
optics. Because the optics have been preset, there is always the
chance that focus may be OK. Adjusting focus and azimuth are
similar for digital and analog. The reader clamp is loosened and
the reader is moved forward or back to adjust focus. When using
the ’scope a correct digital burst, the “Grass”, will be in good
focus and the center area will be somewhat darker, exhibiting
“hollowness”. Using DRAS you are looking for the highest
“focus” number. Expect to achieve high 60s to 70s with our
reader.

10
Azimuth adjustment is difficult when using only a ‘scope. Rotate
the reader to adjust for the flattest perf trace and the lowest error
rate on the processor display. Large azimuth errors are seen as a
tipping of the ‘scope sprocket hole trace. The axis will be the
center of the displayed perf trace. The DRAS azimuth number
you are looking for is as close to zero as possible. Retighten the
clamp screw when both focus and azimuth have been optimized.
Final:
As a final check run Dolby Cat. 69T and observe both digital and
analog levels and the digital error rate.
Analog:
You can go back and double-check the analog setup. Start as you
did before by checking lateral position. It should not have
changed, but if it has, it is OK to refine it. If you did refine it
make sure the Dolby Tone, equalization, scanning beam
illumination and lateral guide are still correct.
Digital:
The last step is to fine adjust the rotation of the digital LED to
minimize the unevenness of the sprocket hole trace. Now run a
piece of film with a good sound track and go sit in the theater and
“test” some really fine sound.