Technical Support Document 033 - 5/97

STARLITE 55 FILTER TRANSPORT ADJUSTMENT

This sheet documents several checks and adjustments for the Starlite 55 Filter Transport. The first item covered is the adjustment of the Filter and Shutter Motor Slip Clutch assemblies, while the second covers the adjustment of the Filter and Shutter motor drive gear engagement into the filter blade gear teeth.

Both of these adjustments must be correctly set for the Starlite colorhead to perform to it's full potential. If an adjustment is incorrect, any of the following problems may result:

The nylon (plastic) gears used in the Starlite 55 Colorhead are mounted on "Slip-Clutch" assemblies to prevent skipping and grinding teeth on the filter blades. These Slip-Clutches are adjusted so that the motor can supply sufficient power to turn the filter blade, but not so tight as to allow the teeth to skip.

There is potential for damage to some of the Filter Transport's components if these adjustments are not set correctly. Particularly, if a Slip-Clutch is adjusted too tightly, the drive belt on that motor will tend to wear out much more quickly than normal. If the Slip-Clutch is very tight, the motor's gearbox may become stripped. As a rule, it is better to have adjustments that are too loose than too tight.

Following are the sections outlining the adjustment of the Starlite Filter Transport's Slip-Clutch assemblies and the adjustment of the Filter/Shutter motor Drive Gear engagement.

I. MOTOR GEAR SLIP-CLUTCH CHECKOUT AND ADJUSTMENT

It is completely normal for these gears to slip as the shaft turns. Below is a drawing of a motor gear. The parts that should be able to slip, and those that are not, are also labeled.

Regarding the above picture, please note the following:

(1) The Arbor assembly (and all the parts that are on it) is pressed onto the end of the shaft. If the arbor at any time slips in its grip on the end of the motor shaft, it should be either replaced or pulled off and glued so that it no longer slips. This kind of slippage is caused by the slip clutch being adjusted too tightly. To decrease the amount of torque required for the slip clutch to slip in the proper way, turn the brass "Slip Torque Adjustment Nut" away from the gear so that it takes pressure away from the spring.

(2) All slippage should occur between the black plastic arbor assembly and the steel washers on either side of the drive gear itself. The gear will also slip within the washers; this is normal. If the Nylon Drive Gear skips teeth on the edge of the filter blade, two things may be done to stop this from happening. First, the Slip Clutch torque may be reduced by loosening the brass nut, as described under paragraph (1), above, or the Drive gear's engagement to the filter blade teeth can be adjusted.

To Check Adjustment:

The adjustment of any Filter Motor or shutter motor Slip-Clutch should be loose enough so that the gear will spin without back-driving the motor itself. In other words, if you manually move any of the Filter blades or Shutter blade, the white gear should rotate, but the Motor Shaft must not.

• To loosen the Slip-Clutch: Rotate the brass Slip Clutch Torque Adjustment Nut so that it moves away from the Drive Gear, releasing pressure on the spring. Remember that it is better to have the Slip-Clutch adjusted loosely than too tightly. After the adjustment has been made, you may wish to secure it in place with a dab of nail polish. DO NOT use "Crazy Glue," "Zap-a-Gap," or any other "super-glue" adhesive.
  
• To tighten the Slip-Clutch: Rotate the brass Slip Clutch Torque Adjustment Nut towards the gear, so that it exerts more pressure on the spring. Generally, you should never adjust the Slip Clutch to a tighter setting unless the Drive Gear is found to be free-spinning with no drive power. When properly adjusted, the Drive Gear on the Shutter motor may feel very loose, almost free-spinning. However, since it takes very little power to move the Starlite's Filters and Shutter Blade, a very loose setting is correct.

II. GEAR ENGAGEMENT ADJUSTMENT

The Starlite Colorhead utilizes four gear motors for the purpose of driving it's three filters and the shutter. Each of these motors has an output gear that drives against the edge of a filter blade, which has teeth to match this gear. The amount by which the gears mesh with the edges of the filter blades affects the performance of each filter's movement. If the gear is pressed too tightly against the edge of it's filter, the computer driving the motor will have trouble positioning the gear in the accurate manner required for closed-loop operation. If the gear is too loose, it may skip on the teeth of the filter blade, causing minor stripping of the gear's teeth.

Before any adjustments are made, first check each motor's present adjustment by moving it's gear back and forth, into, then away from, the edge of the filter blade, as shown here:

There should be a very small amount of free play in the direction of the arrow shown in this drawing. If there is no free play here, the gear is adjusted too tightly.

If, on the other hand, when the filter blade is rotated by hand, the gear's teeth skip on the teeth of the filter blade, the gear is too loose.

If an adjustment is needed, proceed with the following procedure:

This adjustment is done via the small white plastic screws in the Motor Gear Positioning Plate. This plate, and these screws, are pictured below:

These screws control the amount of looseness that exists between each motor drive gear and its filter blade gear teeth. Each blade should be able to be rotated, without any teeth skipping. If there is skipping, adjust the corresponding screw to the point where the skipping just stops. Do not over-tighten these screws, since this will cause binding, and the colorhead will have difficulty in positioning the filters. These screws are very sensitive, and even very small adjustments can make large changes in the operation of each gear.

By adjusting the slip clutch and the gear engagement properly, the operation of the filter drive motors can be made to work very reliably. It may take awhile to get these adjustments right, but the time is well spent, since it will greatly increase the service life of the motors and gears.

If you have any questions or problems with any of the items discussed in this document, please feel free to contact the offices of ZBE, Inc., at the phone, fax, address or e-mail below.