Description; Adjustments - Eiki ESL SERIES Service Manual

6-6 SOUND DRUM AND FLYWHEEL
A. Description
The sound drum and flywheel assembly's main function is to stabilize the film, allowing the
sound optics or magnetic head to read the sound tracks with a minimum of speed variations.
The sound drum, shaft, bearing and flywheel are precision machined and balanced to main-
tain a consistent linear film speed. Care should be used when disassembling or re-assembling
these precision parts.
The sound drum shaft (46) is seated in two precision ball bearings (48) which are sealed and
factory lubricated. The ball bearings are lightly press fitted into the sound hub casting (47).
The shaft is secured in place by a set collar (51 ). With the fiber washer in place, with no end
play in the sound drum shaft, it must rotate freely and not bind. Any binding or imperfec-
tions in the ball bearing will result in excessive wow & flutter. In the forward direction, the
sound drum shaft (46) is driven by the tension of the film. The flywheel is free to slip on the
sound drum shaft during the initial start up of the projector to prevent any possible film
damage. The flywheel brake mounted on the main interlocking bracket stops the rotation of
the flywheel instantly when the function switch is turned to "STOP" so that the film is not
scratched by the sound drum which intends to keep turning. During projection the brake is
off away from the flywheel. (Fig. #97)
B. Adjustments
The ball bearings are life time lubricated and lightly presses into the hub (47). The amount of
shaft (46) end play should not exceed 0.2mm and is determined by the set collar's (51) posi-
tion. Care should be taken not to bend the shaft or lubricate the bearings. (Bearings are
factory lubricated and should be replaced if defective). Defective or incorrect lubrication of
the bearings will result in excessive wow and flutter. The plate spring (54) tension may be
adjusted for minimum wow and flutter with the screw secured. Whenever removing the spring
and flywheel is necessary, care should be taken to avoid changing the plate spring's tension.
Fig. #96
Fig. #97
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