Although we have tested everything herein and found the following tips
to be of excellent advice, these tips are not endorsed by Christie Inc.
and are provided for your assistance "at your own risk".
For the calibration process, you will need a set of standard allen wrenches, a multimeter, flat head screwdriver, a phillips head screwdriver and a 15/32 wrench (for removable brain versions).
Turn the power off to the AW3.
Remove the top platter motor speed control card.
Insert test probes into pins 12 and 14 of the motor speed card connector.
Turn the power on to the AW3.
Set the feed control arm to full throttle (100 degrees) and hold in place.
Read the resistance across pins 12 and 14. Set the resistance to 25K ohm by turning the appropriate LED intensity adjustment potentiometer. Note: clockwise will decrease resistance, counter-clockwise will increase resistance.
Repeat the steps above for the lower two decks. Note: turn off the power to the AW3 before removing test probes.
Set the feed control arm to 20 degrees and adjust the LOW platter speed on the apropriate motor control card so that the platter turns 1/4 turn per 15 seconds. If you cannot get your platter to spin slow enough with the LOW pot turned all the way down, the led assembly probably needs to be replaced.
Set the feed control arm to full throttle (100 degrees) and adjust the HIGH platter speed on the appropriate motor control card so that the platter turns between 5 3/4 to 6 revolutions per 15 second intervals.
Verify the platter does NOT have a "punch" in speed when slowly moving the feed arm from 0 degrees to full throttle. If it does, the LOW adjustment is set too low. This is crucial to keep longer prints from getting thrown.
Repeat for the other platters.
Removable brain prodedure
Note: explosion drawings follow the descriptions for reference.
Remove the brain.
Remove the platter deck, being careful not to pull the two thrust washers and thrust bearing off of the platter axle shaft (#16, 17, 18).
Remove the 4 screws securing the platter axle to the arm (#12).
Carefully remove the entire assembly (#12, 9, 8, 13) by pulling upward at an angle and take over to a well lit work bench.
The control arm spring (#8) is set typically two revolutions "too" tight. Sometimes one revulotion will be ideal, while other times it may take four unwinding revolutions depending on the age of the machine. Note: if this is an older machine and the spring is in less than ideal condition, you will need to replace them completely. The part number is #193877-001. Obviously, you will need three for every platter system.
To loosen the spring, the easiest method is to take a small allen wrench and work the curled end through the filter cam (#7) backwards, to lessen the backpull tension. If so desired, the filter cam (#7) can be removed, but at the expense of having to completely re-guess the setting. We do not recommend that method. Note: loosen/tighten the spring in half turn increents using the two flanges of the filter cam (#7) as stoppers.
Once loosened, insert a brain into the axle and hold level checking for a very slow pull of the feed arm from full throttle (100%) to full stop (0%). This will approximate the final "in platter" setting, although you will find it to be a little off. Adjust until the setting is approximate.
Reinstall the entire assembly (#12, 9, 8, 13) back into the arm by tilting downward at an angle. You will be able to hear and feel when the assembly is back in and seated properly.
Insert two of the original four screws that secure the platter axle to the arm (#12). They need not be tight at this point. They are only there to achieve proper alignment.
Insert a brain into the newly adjusted axle. Note: the platter need not be on. Hold the feed control arm at full throttle (100%) and then gently let go and time it's pull back to full stop (0%). It should take between 1 1/2 to 3 seconds to return all the way to full stop (0%). Note: 2 full seconds is ideal. There should NOT be a definite "snap" back to full stop (0%).
If all checks out, install the other two screws and tighten all four down securely and repeat the test in the paragraph above. Note: some platter arms are machined slightly different than others and you may find that the test works perfectly with the axle is not tightened down, but the arm "freezes" midpoint during it's travel when the screws ARE tightened down. Remove and retighten the spring (#8) one half revolution...or if possible, test to find out which screw causes the arm to freeze and don't tighten that one down fully.
Stationary brain procedure
Note: explosion drawings follow the descriptions for reference.
Remove the brain by first removing the screw that holds the half circle shaped dust shield in place. Note: this screw is located right behind the stationary guide bars (the two white stationary stripper rollers in the center of the brain).
Next, remove the feed control arm by unscrewing the screw at the back end of the feed control arm.
Finally, remove the actual brain plate assembly by removing the two mounting screws in the center of the round black base plate. The remainder of the brain can now be lifted straight up and off of the platter.
The control arm spring (#8) is set typically two revolutions "too" tight. Sometimes one revulotion will be ideal, while other times it may take four unwinding revolutions depending on the age of the machine. Note: if this is an older machine and the spring is in less than ideal condition, you will need to replace them completely. The part number is #193877-001. Obviously, you will need three for every platter system.
To loosen the spring, the easiest method is to take a small allen wrench and work the curled end through the filter cam (#7) backwards, to lessen the backpull tension. If so desired, the filter cam (#7) can be removed, but at the expense of having to completely re-guess the setting. We do not recommend that method. Note: loosen/tighten the spring in half turn increents using the two flanges of the filter cam (#7) as stoppers.
Once loosened, reattatch the feed control arm and hold the feed control arm at full throttle (100%) and then gently let go and time it's pull back to full stop (0%). It should take between 1 1/2 to 3 seconds to return all the way to full stop (0%). Note: 2 full seconds is ideal. There should NOT be a definite "snap" back to full stop (0%).
If all checks out, remove the feed control arm, reinstall the brain plate, reinstall the feed control arm and reinstall the dust shield...in that order.
For some reason, these are always too close to each other (#2, 3). When they are "too" close, they will collect dirt and redeposit them at splices, tug against the pull of the projector causing DTS digital to wow or drop out, and in extreme cases scratch the film!
The procedure is the same for either removable or stationary brains.
Remove the dust shield holding the stationary guide bars. Loosen the two screws securing the stationary guide bars to the dust shield. While partially inserting a finger or pen between them...spreading them away from each other as far as possible, tighten them down.
Reinstall the dust shield.
Now, with film running verify ONLY the sprockets are touching the stationary guide bars. Some brains (depending on vintage) will ride "low" and scratch the non-soundtrack edge of the picture, assuming the soundtrack is up on the platter (projected right side). If this is the case, remove the three brain roller shafts and place a small, thin washer under each roller shaft. Reinstall the rollers and run more film to verify the correct height of the rollers to the stationary guide bars. If necessary, repeat intalling a second small washer. Note: typically one washer will do, however we have on occasion needed to place two below the shaft for proper alignment.
We are referring to the spring in the center brain roller (#10). We do not adjust this at all. We have found the back tension from the brain to be too great regardless of the amount of grease on the spring and can stretch one side of the film if any of the rollers are slightly off line with each other. Our solution is to remove it completely. Allowing the center brain roller to spin freely works perfectly as long as the platter to projector distance is no greater than about 15 feet. Should this distance be greater, a ceiling mounted "helper" roller halfway during it's travel is always our preferred solution. Note: a "helper" take up roller will not be necessary.
At the top and bottom of the slide bar (#3) you will notice some form of screw. The newer ones have allen heads. If yours does not have allen heads, we highly recommend a trip to the local hardware store and the originals be replaced.
Loosen the lower screw slightly and don't worry about it for now. Loosen the upper screw and adjust the bar as high as it will go. Run film on to the top platter. Slowly adjust the bar downward until the film just barely touches the take up platter as it stands straight up and no lower. In essence, the bar should be as high as possible with the film laying flat and smooth on the take up platter.
Run film on to the middle platter. Verify the film lays flat and smooth on the take up deck. If not, lower the bar slightly so that it does, but no further.
Repeat the above paragraph for the lower platter.
Don't forget to go back and tighten the lower screw once you are satisfied with the alignment.
Diagonal scratches typically come from this adjustment being "too low" and the film scrapes along the edge of the platter deck while it takes up...the end result being diagonal scratches! Note: these type of scratches can also happen from loading or unloading a film with the adjustable roller on the make up table being too low also! Make sure all film handlers watch this carefully.
Does your theater use film clamps? If so then the actual surfaces of your platters are probably pretty scuffed up. The action of angling the film clamps downward into the deck in order to try and get the clamps under the film almost always scratches the surface of the platter. These scratches typically have rough spots where tiny bits of aluminum stick up from the surface, causing the film to snag on them and the end result is a thrown print. Plus, with the polyestar prints in use today, a smooth platter will sling the film off center, and sometimes off the edge. The purpose of buffing is to "roughen" up the decks and make "grooves" in them, just like grooves help keep a car on the road when wet. An added benefit of this is the "shiny" and "like new" appearance of the decks.
You will need sandpaper (120 and 220 grits) in 8 1/2 x 11" sheets. One sheet per deck. Note: lower cost contractor boxes of these are typically available at Home Depot type hardware stores. Also needed is a sanding sponge (9x1") also available from the same outlets. Finally, I prefer "ValueChoice" wipers (available from larger paper suppliers) as they are extremely plush, thick and durable versions of paper towels. Regular paper towels will not work sufficiently for this purpose.
Note: do not buff the platters while film is in operation as the flakes will damage the print being run. Also, remove all film from the other two decks and place away from the platter to be buffed. Remove your platter dust covers from the area as well. If you have a projector mounted cleaner, remove it too.
Remove the brain from the platter deck to be buffed.
Attach the make up table and start the platter "loading" at full throttle.
Take a sheet of the 120 grit 8 1/2 x 11" sandpaper and wrap it around the 9x1" sanding sponge. (Note: although the measurements are 1/2 inch difference, we find they line up nicely. Some trimming of the sanding sponge may be necessary, as it should not extend beyond the sandpaper.) With the platter running, start at the center of the platter, applying light pressure, SLOWLY start moving outward to the edge of the platter. Remember, apply LIGHT pressure. The idea is to take off the glaze and smooth out the protruding rough spots. Do not try to remove the deep scratches, you don't want to sand "through" the deck! Take your time. A good pace will typically take a solid minute or so.
Wipe the platter off with the ValueChoice or similar disposable wiper.
Repeat the above procedure with the 220 grit.
Wipe the platter off with the ValueChoice or similar disposable wiper. Note: you may need to go through several "cleanings" of the platter decks before all the shavings are wiped off. We do not recommend using any kind of liquid cleaner on the surface of the platter as it will promote glazing of the surface, defeating the purpose of the buffing.
Repeat these procedures for the other two platter decks.
Now aren't they shiny and like new?
BASIC POINTS TO REMEMBER
*Always run the soundtrack edge of the film UP on the platter. Most damage to platter-run prints happens due to running the soundtrack edge down, against the platter surface. Running the film soundtrack edge UP keeps the potential abrasiveness to a slightly misaligned platter down to an absolute minimum and also stops "faulting" of the print. Running UP keeps the emulsion side away from the brain in the event of dragging and keeps the emulsion away from the platter surface on takeup...eliminating the possibility of colored diagonal scratches. It will also feed smoother into the brain on payout.
*Always run the emulsion side of the film on as many of the rollers as possible. So long as the rollers are spinning, there is no worry...and even if one were to seize up, they are beveled inward and would still not scratch the film. In short, don't be afraid of running the emulsion on them. The base side of the film carries the dust and dirt. That dirt gets deposited on the rollers. The dirt on the rollers gets redeposited on the film. It is a never ending process. By running the emulsion on as many rollers as possible, this is drastically cut down, and prints will stay cleaner, longer. An added benefit is the lack of having to twist and turn the film back and fourth in that "old style" approach.
The following descriptions are assuming the platters are at a slightly turned angle with the closest platter leg "parallel" to the side of the lamphouse. The proper direction of the film should be as follows:
Left side platters (on non-operator side of projector).
Thread the film through the brain and toward the platter tree, twisting
the film so that the soundtrack is against the tree. Follow the threading
pattern down to the lower roller and on the way back up, twist the film
so the soundtrack is again, against the tree (or away from the screen).
Keep the soundtrack AWAY from the screen all the way TO and FROM the projector.
(Bypass the projector at this point.) Upon returning to the platter,
you will once again notice the soundtrack will be towards the tree.
Continue threading with the soundtrack towards the tree all the way to
the take up platter. Now return to the projector and thread it, being
careful not to allow any film to touch the floor. (Note: a
clothespin nearby is handy for this.)
Right side platters (on operator side of projector).
Thread the film through the brain and toward the platter tree, twisting
the film so that the soundtrack is against the tree. Follow the threading
pattern down to the lower roller and on the way back up, twist the film
so the soundtrack is away from the tree (or towards from the screen).
Keep the soundtrack TOWARDS the screen all the way TO and FROM the projector.
(Bypass the projector at this point.) Upon returning to the platter,
you will once again notice the soundtrack will be away from the tree.
Continue threading where the soundtrack turns towards the tree all the
way to the take up platter. Now return to the projector and thread
it, being careful not to allow any film to touch the floor. (Note:
a clothespin nearby is handy for this.)
If there are any further questions or comments, double check our site
(www.film-tech.com)
for recent additions or email us directly. We will try and do
our best to help.