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The sound drum shaft {5} is seated in two precision
ball bearings {3} which are sealed and factory
lubricated. The ball bearings are lightly presr fitted
into the sound hub casting {2}. The shaft is secured
in place by a set collar {6}. With rhe fiber washer
in placa, with no end play in the sound drum shaft,
it msst rotate freely and not bind- Any binding or
imperfections in the ball bearing will result in
excsssive wow & flutter. In the forward direction,
the sound drum shaft {5} is driven by the tension
of the film. The flywheel is free ro slip on the
sound drum shaft during the initial start up of the
proiector to prevent any possible film damage. In
the reverse direct'ron, the set collar {6} ls driven by
the reverse rubber roller, allowing the film to be
transported smoothly across the sound drum in the
r€yers€ direcrion. {Fig. #103, 104, 10S}
B. Adjustffents
The drive torque to the flywheel is determined by
the tension of the plate spring {8}. The normal
torgue should be between 2B -
25 grams. To
chesk this, use a gram scale and attach a string to
Fis. #to4
*_il
,r""=**r"
I
R€VERSE
ERACEET
L-J
leig. #toe the
flYwhe*l with
u I
I r
)rl
adhesive tape. With
SPRING scALE
I l.' -a | *^ +ir- ir +rrr ^-^
REVERSE RUBBER
RT}LLER
FORHAN9
Fis, #tge
20_zseniils-lil no film in the pro-
srwrrcH
tJ iftl
jector, switch to
.nsvenss*fr*Jll revers€ while hold-
ing the gram scale
attached to
the
string. To adjust
this torque, remoye
the plate
spring
and bend to obtain
the corre€t tenEion.
A badly formed
spring should be
replaced-
{
i
#
| *o," oJ,,r=
\
sELr
\
AoHEsrvE rAPE
)-_
|
I (Fis. +106)
Fis. #llE
L s
* 6 0 -
l_ 7
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