Film-Tech

Film-Tech
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Setting up the Projector
Projector Lamp Resistance
A.C. Operaiion
D.C. Operation
Controls
Soundor Silent Films
Lacing Fi[m Through the Projector
Focusingthe Projector Lamp
Lubrication
ServiceCuide
Care of Films
Suggestionson the Choice of Accessories
Hints on the Presentationof an Effective Show
OperatingSide of Projector
Control Panel
Projector Lamp
Top Panel
Front of Projector
Back of Projector
Baseof Proiector
Lacing Chart
'!!
18
19
GeBescope
INSTRUCTI
ON MANUAL
The object of this handbookis to'provide the user with a
generalideaof the operation,and
maintenanceof the C.B.E.Model
L.516 equipment,which has been designedwith a view to portability and simplicityof operation.
Nevertheless,modern sound-film reproducingequipment is
of necessitysomewhat complex, demandinga reasonableamount
of careful handlingand attention if a high standardof efficiency
is to be maintained.
The descriptionsin this manual have been kept as brief ancj
non-technica:l
as possible,and if the instructionsare followed
carefully,the equipmentwill give good resultsand little trouble.
Shouldany difficulty ariseor the userdesirefurther technical
information,pleasewrite direct to the addressbelow.
Purchasersof "GeBescopes"who experienceany difficulty
in manipulatingtheir projectorsshould,in the f,irstinstance,refer
the matter to the Dealer from whom they were obtalned. The
Dealer will, if the matter is one that should be handledby our
own engineers,.
at once arrangewith us for servicing.
All correspondence
concerningthe servicingof "CeBescopes"
should be addressedto:-
1 5 m m . S E R V I C ED E P A R T M E N T
G..B.EGIUIPMENTS
TIMITED
wooDcER RoAD,SHEPHERD'S
BUSH,
LONDON,'W.12
IMPORTANT.-ln any correspondence,
pleasequote serialnumber
of the unit or componentas this will minimisedelay.
| 1th Edition
,t
1,,
G.B.Filmlibrary
is ready to .rerueTou
HE G.B. Film Library is equippedto meet your every
16mm need with a fine assemblyof quality films in sound
or silent, black and white or colour.
More than 300 major features alone are already available
rncluding many fine British productions, with several, such as
HenryV,in Technicolor. Your choice of Artistes is served by over
100 stars of screenand stage. There are hundreds more fine films
from which to choose-documentaries,comedyand variety ' shorts,'
films on sport, travel, religious subjects, films specially made for
children. Then there is the special category of the G.B. Library
devoted to educational and general interest films-on biology,
natural history, geography, history, physical education andmany
other subjects.
All these films and the servicesof l6mm experts are at your
disposal. The G.B. Llbrary, built up over 15 years, is specially
designed to render a complete film service-to answer any
problem on film presentationand
help you to get the best from
16mm films.
The latest film catalogues will
describe how easily you may
obtain and enjoy 16mrn films
from the G.B. Library. Please
specify if you require Catalogues
of entertainment sound films
and/or of educationalsound and
silent films.
::$;
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- : "
Write to:
G.B. 16mm FILM LIBRARY,
Aintree Road, Perivale,
Middlesex.
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t N S T R U C T t O NFSO R E R E C T t O N O
, pERATtON
AND MAINTENANCE
SETTING
UP.
R e m o v et h e t o p c o v e r o f t h e p r o j e c t o r a n d r a i s e t h e s p o o l a r m s t o t h e r u n n i n g
p o s i t i o n . M a k e s u r e t h a t t h e s p o o l a r m c a t c h e se n g a g e . ( F i g . l . ) p l a c e a s p o o l
of the required capacity on the take-up spool arm for taking up the film. press
d o w n t h e s p o o l r e t a i n i n gc l i p . ( F i g . l . )
The projector is despatched with the valves and lamps in position. The
spool arms are releasedfor folding by pressing on the spool arm catches. The
take-up arm should be lowered first.
MAIN SUPPLY.
T h i s m a c h i n e i s d e s i g n e df o r o p e r a t i o n w i t h a l a m p r e s i s t a n c ef r o m a 2 O O / 2 5 0
,l,275
v o l t A . C . o r D . c . s u p p l y s u i t a b l e f o r a c o n s u m p t i o no f
w,atts. For loO/ll0
volt operation, a transformer is required for A.C. or a converter for D.C. for the
m o t o r a n d a m p l i fi e r s u p p l y .
P R OE
| C T O RL A M P R E S I S T A N C E( F
. is.3.)
THE LAMP RESISTANCE
HASA SPECIAL
VOLTACESELECTOR
FORTHE
V A R I O U SM A I N SV O L T A C E S
W, H I C H M U S TB ES E TB E F O RC
EO N N E C T I N C
UPTO THE MAIN SUPPLY.ALWAYSCHECKTHESUPPLY
VOLTACEBEFORE
A D J U S T I NTGH ET A P P I N CP L U C .
,
,
,
]
',
As the lamp is rated at I lO
v o l t s a r e s i s t a n c ei s u s e d t o r e _
duce the voltage when using
the projector from a 2OO/25O
volt A.C. or D.C. supply. The
resistance is connected to the
four-pole socket in the back of
the projector case. Care must
be taken to see that the tapping
p l u g o n t h e r e s i s t a n c ep a n e l i s
screwed firnrly into the socket
marked with the voltage
nearest to the main supply. On
nc account must the resistance
be connected to tfre projector
with the tapping plug screwed
into the I lO volt socket when
using the projector on 2OO/25O
volts A.C. or D.C. lf required,
a transformer may be used instead of a resistance when
operating from 2OO/25O volts
A C only, to reduce the consumption from the mains from
I.275 watts to 750 watts.
TRANSVERTE
PR
I U G 1 F i s2. . )
This is situatedabovethe mainspiug on the control paneland must be kept
in positionwhen usingthe machineonzoo/250 volts A.c. or D.c. A transformer
or convertermust be used for a loo/l10 volt A.c. or D.c. supply respectively,
and is connectedto a four-poleplug which replacesthe existingtransverterplug.
The motor and amprifiercan onry work from 2oo/250 vorts A.c.
or D.c",
hence the necessityfor a step-up deviceas mentionedabove.
R E S I S T A N CPEL U G
rApptit6
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M A I N SC O N N E C T I O N S .
M A K E C E R T A I NB E F O R C
E ONNECTINC
TO THE MAINS THAT THE
L A M P R E S I S T A N CTEA P P I N CP L U CO R T R A N S F O R M EI S
R A D J U S T EF
DO R
T H E V O L T A C EO F T H E S U P P L YA N D T H A T A L L S W I T C H E S
ARE IN THE
"oFF"
POStTION.
Connect the socket on the mains lead to the three-pole plug on
the control
panel (Fig. 2); this should be made before connecting tp the
mains. As the
p i n s a r e s t a g g e r e d ,t h e m a i n s s o c k e t c a n o n l y b e i n s e r t e d
one way. connect the
other end of the lead to a convenient power plug. When using the projector
on
D . c . m a i n s e n s u r e t h a t t h e m a i n s p l u g i s c o n n e c t e dt h e r i g h t w a y r o u n d ,
other_
wise no sound will be obtained from the amplifier, in which case reverse
the
power plug or connections.
I
The mains lead is providedwith an earthingwire, which is connectedto the
three-polesocket so that the machine may be earthed. Where a power point
is fitted with a three-poleplug, connectthe wires, red and black to the mains,
and white to the earthing pin.
The pilot lamp lightsas soonas the main supplyis connectedto the machine.
voLT A.c. oPERATION.
2001250
Connectthe projectordirect to the mains,as above,and the lamp resistance
or transformerto the socket in the back of the projectorcase (Fig. 3). Make
sure that the resistanceor transformeris connectedto suit the supply voltage.
ro0ll,l0 votT A.c. oPERATION.
Connectthe projectordirect to the mains,removethe transverterplug and
c o n n e c ta n L . 5 1 6 1 O 0 / 1 1 0v o l t t r a n s f o r m e r .
The lamp resistanceor transformermust be connectedaccordingto the
supplyvoltage.
TAPPINC PLUC
OR TRANSFORMER
CAUTION.-THE LAMP RESISTANCE
T O T H E I I O V O L T S O C K E TW H E N U S I N C T H E
MUST NOT BECONNECTED
pRoJECTOR
FROM200/250voLTs A.c. oR D.c.
20ol250VOLT D.C,OPERATION.
connect as for 200/250 volt A.c. supply,usinga lamp resistance.
rool4,l0votT D.C.OPERATION.
Connectthe projectordirect to the mains,removethe transverterplug and
c o n n e c ta n L . 5 1 6 1 0 0 / l l 0 v o l t D ' C . c o n v e r t e r .T h e lamp resistancetapping
plug must be connectedto the I I O volt socket.
TAPPINCPLUC MUST NOT BE
CAUTION._THELAMP RESISTANCE
WHEN USINCTHE PROIECTOR
VOLT
SOCKET
llO
CoNNECTEDTO THE
FROM2O0/Z5OVOLTSA.C. OR D.C.
coNTROtS
MOTORswlTcH. (Fis.1.)
This is located on the front panel and is mechanically linked with the film
trip lever which switches off the mechanism. The mechanism can only be
started by the motor switch.
FltM TRIP LEVER.(Fis.1)
This is a safety device which switches off the mechanismand projector lamp
if the loop beneath the gate tightens up, due to incorrect lacing or damagedi'ilm.
The film must not be in contact with this lever, otherwise it will trip as soon
as the machine is started. Reset the trip and restart the mechanism by moving
"on" position.
the motor switch to the
mechanism is started by the motor switch and stopped by
NOTE.-The
iifting the film trip lever. The mechanism cannot be started by the film trip
or stopped by the motor switch.
6
STltLPICTURE
CTUTCH
(Fis.1)
t1,J,:,:l_T::_i:y,be projectedby movingthe crutch
teverfrom right to
moigrfromthe."".r,r"ir-,La i,,"0."""';":i:;;;;
f?1,.;,
,InJ:^jl.::r.p"._,lle
b,tistering
oj:;'"''
sareto.prevent
nt
l,ll"::
"T'lil,lh:,
?i:rrl".
is
obscu
red,
rota
te in!'
l,.f,,ie' [,jiol" IF?J.
ir.,"i,rir]" rf",il";il;"
. To changefrom stiil to mlving pictures, depressthe smail reverbeneaththe
clutch lever and move to the rightl
FOCUS|NGKNOB. (Fis. 1)
The knob for focusingthe picture sharpry
on the screenis situatedon the
lens mount' When setting up the machine.
it is necessary
to approximatery
focus
the picture on the screenby pushingthe rens
to and fro with the fingers rvith
the focusingknob in-the."nir" positiln, so that
a final adjustmentcan be carried
out by rotatingthe focusingknob to the right
or left.
TAKE-UP
CIUTCH.(Fis.4)
The take-up clutch is fitted to the spoorshaft
on the rear arm. By rotating
the knurled ring the tensionon the film from the
take-upsprocketmay be varied
accordingto the size of the spoor and hub.
N;;il;
il";";;;"r;;;;
should be used for a r,600 foot spoorby scr"*inj
ro',r.," ring in a crockwise
direction. Lesstensionshourdbe appriedfor 600
"i-ra+oo foot spoors. rf neces_
sary,the tensionmay be alteredwhiist the machineis
runninj. Too much tension
may causefilm dam:ge.
, ,
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BEIT. (Fis.1)
TAKE-UP
This may'be replacedby disconnectingit at the joint and pushingthe new
belt through the right end of the slot in the panel,until it appearsthrough the
oppositeend. The belt may then be ioined by engagingthe hook and loop.
RACKING KNOB. (Fis. 1)
This control is placedat the top of the film channel. lf there is a black
divisionor framing line acrossthe top or bottom of the picture,rotate the racking
knob until the picture is correctlyframed.
VOLUME CONTROL. (Fis. 2)
The volume is controlledby the right hand knob mounted on the control
panel. To obtain best results do not increasethe volume of sound beyond that
necessaryfor comfort. A clockwise rotation increasesvolume and vice versa.
This control is not operativewhen using either a microphoneor gramophone
attachment,but shouldbe kept at zero to preventthe reproductionof the perforationswhen projectingsilent films..
TONE CONTROI. (Fis. 2)
The pitch of the sound may be variedaccordingto requirementsor acoustic
propertiesof the auditorium,by rotating the knob next to the volume control.
A clockwiserotationwill increasebrilliarrceand vice versa. A greatdeal depends
on the settingof the tone and volumecontrols,so that a certainamountof experiment is advisableto get the best possiblereproductionfrom the sound track.
SOCKET.(Fis.2)
SPEAKER
This is the four-polesocketon the control panel. lt will be noted that the
socketsare staggeredso that care should be taken when insertingspeakerplug
to locatethe pins correctly. The mains shouldbe disconnectedbefore inserting
or withdrawing the sPeakerPlug.
IAMP swtTCH. (Fis.2)
PROTECTOR
L
This is situated on the contro[ parreland is used for switching the lamp
on or off whilst the mechanismis running. The lamp cannot light whilst the
motor is stationary,unlessthere is a fault in the transformer,converteror transverter plug when using 100/l l0 volt mains. lf the lamp lights when the motor
is stationary,switch off immediatelyto preventblisteringthe film or lamp.
GRAMOPHONE fACK. (Fis. 2;
or microphoneattachmentof the correcttype may be plugged
A gramophone
into the iack on the control panel. Both attachmentsmust be fitteC with a
volume control.
--------
l N C H l N cK N OB . (F i e .2 )
The inching knob recessedin the rear of the projector
caseshould be rotated
clockwise to move the firm graduaily through
the projector to make sure that
the claw engageswith the perforationswhen racing
fiim in the machine. This
control is also used for showingstill pictures,one
at a time.
SOUND OR SITENTFII.MS.
tL
b
. o n t h e f r o n t p a n e rt h e r e i s a s m a i ls w i t c h m a r k e d , , s o u n d , , a n c , , s i r e n t , ,
(Fig. I ). By placingthe switch
in the appropriateposition,either type of .film
mqy be projected at the required speed. When
using sirent firms, it is
advisableto changethe flicker shutter. Normally a two-b'iaded
shutter is used
lor Soundfilm projection,but when the speed'ofthe motor
is reducedfor showing
silent films, the flicker wiil'be increased,
due to the srowerspeedof the motor.
Bv replacingthe original shutter with one having
three bladl;;;
,l;i;;,,
be reduced and tlrerefore become unnoticeabre. To
change the shutter it is
necessary
to removethe three flicker shutter cover fixing screws-(Fig.
I )-so
that the cover may be removed. A "c" spanner is supplied
to fit into tr..,eholes
round the edgeof the shutterclampingring so that lt may
be unscrewedto permit
the two-bladed shutter to be removed. The shuttei
bt"a" should .be held
firmly so that the clamping ring may be unscrewed
by turning it i;; .r""r"'.
clockwisedirection,as viewedf rom the rearof the case. when
the clamping ring
is unscrewedsufficiently,the shuttermay be withdrawn. Before
placingthe threel
bladedshutter in positionnote carefullythat on one side there
is a flangewhich
must fit into the rebatedhalf of the shutter bosson the side
nearestthe picture
lens. The shutter shouldbe pushedinto positionand the clamping
ring tightened
u p u n t i l t h e s h u t t e r i s h e l d f i r m l y a n d s q u a r e l yi n p o s i t i o n .
ir atr".JorJ."-"ni
is carried"-out
correctly,the clampingring and bossshourldbe separated
by only
the thicknesssof the flicker shutter blades. On no account
must the screws
holding the flicker shutter boss on to the main horizontal
shaft be loosened,
otherwise the assembrymay be thrown out of svnchronization
and cause a
"ghost."
After charrgingthe shutter, turn the mechanismby
the inching knob
to see that the bladesdo not foul the main frame.
IOUD SPEAKER.
The speakerlead is containedin the back of the speaker
case and should
be connectedto the speakersocketon the control panel (Fig.2).
When rho*ing
soundfilm, the back of the speakershsuld be rsmeys6to
obiain best reproductionl
;
OPERATION.
The eguipment, having been connected up, is now ready
for operation.
Before lacing filnr into the machine,switch on the motor
and ramp for a preliminary test. Turn up the vorume contror and if
a sright hiss is heard,
it may be assumedthat the amplifier is working. Centre the
light on the screen
and if necessarytilt the projector by looseningthe locking
knob so that the
elevating feet slide out (Fig 5). Tighten the knobs when
sufficient tilt is
obtained.
LACING FIIM THROUGH THE PROfECTOR. (Fis' 1)
Place the spool of film to be projectedon the feed spool arm with the
perforationsnearest the operator. Press down the spool retaining clip and
unwind 4 feet of film. Open the sprocket cradlesby pressinggently on the
releaseknobs and moving down. Lace the film between the film entry rollers
and carefullyround the feed sprocket,making sure the perforationsengagewith
the sprocket teeth. Close the sprocketcradle, leavea small loop and lace the
film through the channel is to lay it along the top of the side runnersand pass
pushed
runner. furthest from the operator, is sprung and therefore has to be
the
lacing
method
of
The
best
channel.
aside to allow the film to enter the
pass
and
runners
film through the channelis to lay it along the top of the side
it to the right of the bottom
l'
'
'
i
f ilm guide. The f ilm should
then be held at the toP of the
channel and gentlY Pulled into
the channel from the bottom.
The tension thus Placed on the
film will move the sPrungsiCe
r,rnn", aside so that the film
will be held in the channel
under side pressure. From the
bottom film guide leave a looP
and pass the film under the
trip lever, over the sound drum,
under the flywheel roller, and
from the right hand side of the
idle roller above the f lywheel to
the left of the jockey roller,
over the roller by the take-uP
sprocket and round the underside of the sProcket. Af ter
making sure that the Perforations and sprocket teeth coincide, close the sProcket cradle
and pass the film between the
f ilm entry rollers to the take-uP
spool. All slack film between
a downward movement of
the take-up sprocket and spool must be taken up by
prevent a sudden ierk on starting'
the take-up belt before starting the motor, to
c
l
o
c
k
w
ise direction' Small loops should
N o t e t h a t t h e s p o o l r e v o l v e si r r a c o u n t e r
drum, and flywheel and take-up
be left between the film channel and sound
as those shown on the lacing
s p r o c k e t . T h e f i l m l o o p ss h o , ; l d b e a d i u s t e d , e x a c t l y
chart.
frequently to the lacing
when first lacing film through the projector, refer
r
e
v
o
lved to ensure that the
b
e
chart (Fig. B). The inching knob should then
through the proiector satisfacc l a w e n g a g e st h e p e r f o r a t i o n s a n d t h e f i l m m o v e s
torily without lossof the looPs.
to
i;
Beforestarting the machinemake sure all cradlesare closed,put the pro"off"
position and turn the volume control to zero.
iector lamp switch in the
Start the motor and run through a foot or so of film to make sure that the
proiectoris correctlylaced. When satisfiedon this point, restartthe motor and
when the titling is running through,switch on the projectorlamp and turn the
volumecontrol to the volume required. Focusthe pictureon the screenif necess a r yw h i l s t t h e t i t l i n g i s r u n n i n gt h r o u g h .
At the end of the picture reducethe volume to zero and switch off the
lamp to prevent showinga white screen.
't
I
I
t ---
F i g6 .
PROIECTORLAMP.
t
I
F
The lamp in this model is rated at ll0 volts, 500 watts with biplane filam e n t s a n d i s f i t t e d w i t h a p r e f o c u s s e dc a p , w h i c h f i t s i n t o a b a y o n e t h o l d e r s o
designed that the lamp can only be placed in the correct position. To replace
the lamp, remove the louvred lamphousecover and the lamp-holder fixing screw
A (Fig.4). The lamp and base may then be removed by pulling upwards on
the composition platform through which screw A3 passes. The old lamp may
be removed from the holder by pressingdown on the lamp, turning to the left
and sliding it out of the holder. A new lamp may be inserted by reversingthis
procedure. To prevent premature failure of the lamp it is essential that the
voltage on the lamp contacts does not exceed ll0 volts as measured by a suitable
meter. The resistance or transformer tapping plug should be adjusted accordingly.
tl
FOCUSING
THEPROIECTOR
IAMP.
lf brown streaks appear on the screen the lamp probably needs focusing.
To simplify this adjustment and to give it a greater degree of accuracy, it is best
to use a magnifying or reading lens. Switch on the lamp, and focus the gate
aperture on the screen. lf the reading lens is placed at a distance of approximately one foot in front of the projection lens, the image of the filaments will
b e s e e n o n t h e s c r e e n . l t i s n e c e s s a r yf i r s t t o a d j u s t t h e l a m p s o t h a t t h e f i l a m e n t
'imagesare in the centre
of the projected circle of light. In the event of the
l a m p r e q u i r i n ga d j u s t m e n t i n t h e v e r t i c a l p l a n e , t h e f i x i n g s c r e w c - ( F i g . 4 ) s h o u l d b e l o o s e n e da n d t h e l a m p - h o l d e r a s s e m b l y m o v e d u p o r d o w n u n t i l t h e
filamentsare centred. FixingscrewsB-(Fig.4)-should
b e l o o s e n e dt o p e r m i t
lamp to be moved and centred in the horizontal plane. Make certain that all
the screws are tightened up after adjustment,
%
,r-*-*;a;;;
I
;;
:
S e c o n d a r yf i l a m e n t i m a g e sf r o m t h e m i r r o r w i l l a l s o b e v i s a b l e .F o r m a x i m u m
light distribution it is essential to get the refiected images between the actual
images. The mirror adjusting nut-(Fig.
I ) - s h o u l d b e l o o s e n e da n d m i r r o r
m o v e d u n t i l t h e r e f l e c t e d o r s e c o n d a r yf i l a n r e n t i m a g e s s h o w b e t w e e n t h e a c t u a l
filament images. Tighten the nut when the best position is obtained. lt is
important that a space of at least an eighth of an inch be left between the
envelope of the lamp and the back of the condenser lens, otherwise the glass
will btister and crack the lens.
12
i l
j t
PIIOT LAMP. (Fie. 1)
This is a l6 volt,3 watt miniature ramp,
which providesilumination for
the control paneland operatingsideof
the mechanismfor lacing. lt also indicates
that the main supply is connectedto the projector:
IUBRICATION.
Three small oil holesin the top panerof the
machineand one in each spool
arm shaft bearing- (Fig. 4)-and one in
the sound drum'collar,s u p p l ya l l t h e
necessaryparts of the mechanismrequiring
oil.
I
t-
IMPORTANT.-ONLY ONE DROPOF GEBESCOPE
SPECIALCRADEZ OIL
M U S T B E U S E DE V E R YF O U RO R F I V E R U N N I N C
H O U R SO R ' E V E R YM O N T H
IF THE MACHINE IS NOT IN USE.
The claw mechanism-(Fig. r )-need onry be packed
v\rithrubricantevery
60 to 80 runninghours..speciarregraphinerubricant
may be appriedby removing
the four corner screws in the front cover prate and
c"refrily withdrawing it away
from the claw box. sufficient Tegraphineshould
be addedto half fill the spaces
above and below the craw arm when in the centre position.
A smail quantity
of the lubricantshourdbe appriedto the cam and pivot
movement.
Do not over lubricatethe machineor allow oil or grease
to come into -""'""'
contact
with any parts of the mechanismnot indicatedabove.
i -some motorsare fitted with oilite bearingsand thesecan
be identifiedby a
labelaffixed to the motor cover. Thesebearingsonry
require rubricati
ication every
1 0 0 r u n n i n gh o u r s .
The procedurefor lubricatingthe motor bearingsis as follows.(a) Open the back flap.
(b)
Remove the screw located a t t h e b o t t o m l e f t - h a n d
corner of the
motor cover plate and also the two screws holding
the top of this
plate.
(c) Withdraw the motor plate,taking
care not to lose the spacingsleeve
locatedbehindthe bottom screw.
t
f
(d) Two oilwaysare,indicatedby a red
dot on top of the motor casting:
apply one drop of oil to each.
( e ) W i p e o f f a n y s u r p l u so i l .
(f) Replacethe cover plate, screwsand distancesleeve,
starting with the
bottom f ixing screw and sleeve.
It is essentialto seethat the motor is not over-lubricated,
otherwiseoil will
penetratethc motor windings,brushesand governorassemblies,
and causea pre_
mature failure of these components
t3
S E R V I CG
EU I D E
MOTOR FAILS TO RUN. Section {.
(a) Mains plug or socket not making contact. check both ends
and
internal connectionsto plug and socket.
(c) Transverter plug not making contact. Check contacts and internal
connections. lf using lOO/110 volt mains the plug may not be
making contact as above,oF connectionsto transformeror tonverter
may be at fault. In this case,the motor will not run, but the projectorlampwill light when lampand motor switgh is in {he,,on"
position. lf this happens,switch off immediatelyto prevent blist e r i n gt h e l a m po r f i l m .
PROfECTOR LAMP Wltt
NOT tlcHT.
Sectirin 2.
(a) Lamp switch not on.
(b) Lamp burnt out.
( c ) C h e c k ( a ) a n d ( b i S e c t i o nl .
' (d) Loose connection in the connectors,or tapping plug
not screwed
firmly into position.
(e) Lamp"contact springsnot making positivecontact.
PILOT IAMP WltL NOT LIGHT. Section 3.
(a) Lamp burnt out.
(b) Valve or barretterburnt out. Changeeach in turn.
( c ) C h e c ka l l p o i n t su n d e r S e c t i o nl .
I
NO SOUND. Section 4.
(a) Volume control nof turned up.
,
(b) Proiectorlamp burnt out.
i
t .
t
(c) Faulty valve or barretter. Changeeach in turn.
(d) Speakerplug making bad contactor plug connectionsfaulty. :
(e) Light from projector lamp to sound track obscured.
(f ) Check all points under Section l.
(g) lf on D.C. mains,r€versemainsplug or connections.
. (h) Check (c) SectionL
LOW VOLUME.
Section 5.
(a) Faultyvalveor photo electriccell. Changeeach in.turn.
' (b)
Low recordinglevel of film.
(c) Foreignmatter on sound optical lens in the bottom of the projector
famphouse.This may be cleanedwith lens tissueif'necessary.
(d) Projectorlamp out of adjustmentor f ilamentsbadlydistorted.
1A
,
- "-
UNSATIIFACTORY
SOUNDeUAUTy. SecrionG.
(a) Motor speedswitch in "Silent" position.
(b) Flywheel not revolving. Remove
bottcjm cover and make sure that
nothing is fouling the flywheel.
( c ) Faulty valve. Changeeach in
turn.
( d ) Variation in film recording.
( e ) Rollersnot revolvingf reery.
Removeand crean,rubricateand reprace.
( f ) sound drum not revorving.
Note that the drum retainingscrew hasa
left hand thread. Removeand crean. Make
sure d"" il;; on the
flat pressure.spring
locatein top and bottom grooves. Lubricatethe
sound drum bearingshaft.
(g) Speakerconeout of centre.
(h) Pooracousticprlpertles
of auditorium.
POOR PICTUREBR|IL|ANCE. tecrion 7.
(a) Projectorlamp discoloured
or out of focus.
(b) Mirror out of adjustment.
(c) Lamp resistanceor transformer
tapping in rvrongposition.
(d) Low mains voltagewhen
working on IOO/llO volt supply.
(e) Film printing.
(f )
Ref lective properties of screen p o o r o r i m p a i r e d .
(g) Condensation on projector
lens. Remove ancl clean with lens tissue.
FltM TRIP IEVER STOpptNGPROfECTOR.Section
8.
( a ) F i l m i n c o r r e c t l yl a c e d .
(b) Broken or split perforations,
in which case the
should be
examinedand, if possible,repaired.
(c) Film in brand new or "green"
condition. This may occur if the firm
has not hardenedoff, in which case it shourd
be reft ""por"J *o "
warm atmospherefor twenty_four hours.
}
a.
t
+'
DARK or ,FUZZY' EDGESON P|CTURE. lection
9.
(a) Fluff or other foreign
matter on the picture gate aperture. Remove
the picture lens and insert a camel hair
brush down the lens tube
to clean the aperture.
REpLActNcvA[vE, BARRETTER
OR PHOTOCEtt.
(Fiss.6 & 7)
"rf",,.',,
CL 33,s:
,
;lL
""ilx?l;rTJi;,#?;.,#"":1".,i"1
,[",T':::i
l""il"l.l.:i:;
tLxilJ,,l]
orbarrette.,
"rw"v.-*,,r,'a'"',i
;";:xi# J;5ffi 1i"[".":#'ji:;
The valves used are first stage, EF36;
output 2;
The first stage
e t q 6 s valve
vqrv' d
and
r r u photo
e l l are
a r e ccontained
ontained in
P n o r o ccell
base of the machine-(Fig.7i-access
to which
enveldpe.
the'rnetal box in the
i s o b ttained
a i n e d by
b v removing
r e m a v i n o the
rha
thenthe two knurtec
knobs"""*r..'"f"".""ii"tol'jl
:::9"I:9
f:l:l::"ur,anJ
of
the box should
then be carefuty
withdrawn to exposetne ,rarue;;;
J;;;
l5
;i;
C A R EO F F I T M S
Cinematographfilms are costly to produceand difficult to replace. Every
possibleprecautionshould,therefore,be taken to preventf ilm damage. Furthermore,your GeBescopecan operate only as well as the conditionof your films
permit" lf the following advice is observed,film troubles will be reduced to a
minimum.
Beforebeginningyour film programme:I . Allow your Projectorto run for several,minutesbefore insertingthe
film, to securesmooth runningat constantspeed.
2. Examineall moving parts to ensure that t h e y a r e running f reely.
Lubricate the Proiector,accordingto the directions g i v e n i n the Instruction
Manual.
3. Make surethat all surfacescomingin contactwith the films are clean,
and f ree f rom depositsof emulsion.A depositof hard emulsionin the picturegate
might ruin many reelsof films, involvingseveralpoundsworth of damage. A
metal instrument must never be usedfor removingemulsionfrom any part of the
machine. A boneor hardwoodscraperwill cleanwithout scratchingthe polished
surfaces.
cleanthe picturegateof youi Proiectorafter
4. Examine,and if necessary,
running through every two or three reels.
5. When removingthe f ilm f rom the container,make sure that the spool
has not been bent in transit. Perforationscan be torn and films scratchedby a
bent spool. lt is essentialto removethe damagedsectionsof the film, and make a
join. Brokenperforationsinvariablylead to further damage'
CHECK BACK OVER LACINC TO MAKE SURETHAT THE LOOPSARE
CORRECT.AND THAT ALL SPROCKETTEETH ARE ENCACED IN FILM PERTO THE TAKE-UP SPROCKET,
FORATIONS. THIS APPLIES.PARTICULARLY
.AND
IS VITALLY IMPORTANT IN ENSURING FREEDOM FROM FILIV.
DAMACE. Care must also be taken to see that the perforationsare securely
film on
locatedon to the sprocketteeth beforeclosingthe cradleswhich keepthe
"trapped"
the sprocket. Inattentionto theseinstructionsmay causethe f ilm to be
on to the teeth,which may tearor punch holesinto the f ilm base. Set the take-up
clutch to suit the capacityof the spooland sizeof hub'
Having laced the Proiector,turn the inching knob four or five times and
watch the film to seethat it passescorrectlythroughthe mechanism.
t6
While projectingyour programme._
Check film perforationsat frequent intervals
by allowing the film to run
lightly betweenthe forefingerand thumb at the point
at which it leavesthe
projector and before it r:eachesthe take-up
spool. lf the perforationsare
damaged,stop the,projectorand investig"ieth"
cause.
.
Perforationscan be damagedby:_
(a) lncorrect threading (perforations
teeth).
not registeredwith the sprocket
(b) Damagedsprocketteeth.
(c) Crad_le
rollersout of alignmentwith sprockets.
( d ) F i e r c et a k e _ u p .
Examinethe emulsionon the film regularly
in the light of a torch shone
obliquelyacrossthe surface. lf scratciesappear
eithei "" o'.ar* .,. .o"ro
track, stop the projectorat once,unracefrom
the take-up,pro.t "t, ;J;.othere tracebdck until the causeof the damageis
found.
Scoiedemulsionis generallycausedby:(b) Dirty rollers (causing
intermittent scratch)
(c) Sounddrum scored
or not revolving.
(d) Too largeor too smail
a roop (causingfirm to drag on anotherpart
of the machine).
Be sparingin oiling your ceBescope. A
little oil frequently,with all surplus
wiped off whereverit may appearon the
machine,shourdbe the rure.
HINTSON JOINING
Lap only one perforation, not two or three,
a n d n e v e r c u t through a perforation when joining.
see that the emulsionis scrapedfrom one side of
the firm to be joined and
that the celluloidis perfectlycrean,otherwisethe join
wiil not hord.
when joined,the firm shourdbe in rine and the perforations
register,otherwise the film will jamb at the
ioin when projected.
Make your join as cleanand as neat as possible.
Rememberthat everythingmechanicalneeds
some care and attention.
Payattention to the foregoingdetailsand firm
damagewiil be reducedto a
minimum. Your equipmentwilr then give
the best possibleresurts. The Libr'ary
will also be able to give you a servicefree
from the rossof time and money
reguiredby constant repairs.
17
ON THE CHOICEOF
SUGGESTIONS
ACCESSORIES
Choosea screengiving a picture which will be in proportionto the size
of room or hall in which the equipmentwill be used. Roughly,the picturewidth
should be not lessthan one-ninth of the distancefrom screento farthest seats.
The front seatsshould not be nearer to the screenthan two and a half times
its width.
The choiceof screensurfacedependsto a largeextent on the shapeof the
auditoriumand positionof the seatingrelativeto the screen.
A white opaquescreenis desirablewhere the viewing angle is very wide,
as its brilliancydoes not fall off rapidly when viewed from the sides. When
give as
viewed from directly in front, however,a white oPaquescreendoes not
b'rillianta picture as a silverscreen'
where the angle of viewing does not exceed about 25 degreesa silver
but
surfacewi ll give a much more brilliant picl'urethan a white opaquescreen,
lessefficient when viewed from a wider angle.
is considerably
A glassbeadedscreengives a very brilliant picture when viewed directly
of brilliancy falling off very rapidly
from the front, but has the disadvantage
as.soonas the angleof vision is increased.
The height of the screenshould be such that the angleof vision from the
top of the picture to the front seatsdoesnot exceed35 degrees.
stanc
Pro.iector
A firm stand for the proiectoris essential.The CeBescope
is not only light, but can be folded up for transport'
for
Extra lensesare desirable,particularlywhere the equipment is used
will
prolector
different lengthsof throw. The 50 mm. lens suppliedwith the
at 21 feet'
wide
inches
3
4
feet
or
42feet,
at
give a picture 8 feet 6 incheswide
35 mm',
of
length
focal
a
having
lenses
and so on proportionately. GeBescope
30 feet,
a
t
w
i
d
e
6 5 m m . , 7 5 m m . a n d l O l m m . , g i v i n ga p i c t u r eo f B f e e t 6 i n c h e s
Reference
can be purchasedif required.
55 feet, 64feetand 85 feet respectively,
t
h
i n d i c a t e e l e n s r e q u i r e d f o r a g i v e nt h r o w a n d
to the 6fis1f-(Fig.9)-will
vice versa.
from
A f i l m s p l i c e ri s e s s e n t i aflo r r e p a i r i n gf i l m s a n d j o i n i n g s e q u e n c e s
mm'
l
6
a
n
d
m
m
'
m
m
'
,
9
'
5
B
t
a
k
e
p r i v a t es h o t s ,e t c . H i g h q u a l i t y s p l i c e r st o
f ilms can be purchased.
the
Although it is possibleto rewind film on all ceBescopeproiectors,
method is to use a hand rewinder,so that the film may be examined'
professional
repaired,whilst rewinding. Brokenor split perforations
cleanedand, if necessary
and forefinger'
can easilybe detectedty ,unning the film between the thumb
head mounted
The ceBescoperewinder comprisesone fixed and one winding
capacity'
feet
1,600
to
spoolsup
on a firm baseand accommodates
l8
.A GeBescopegramophoneattachment is ideal
for supplyingmusic, etc., for
aff purposes. The motor is universal for A,C./D.C. loo/z5,o. An inject is fitted
so that a microphonemay be used at, the same time. A separatevolume control
is fitted as standard
For public addressor supplying commentary tor silent films a GeBescope
microphoneand headamplifier is invaluable.The unit comprisesa self contained
head amplifier with a separatevolume control and microphoneof the crystal
type, mounted on top of a panel.
Every projectionistshould be sure that he has an adequatesupply of spares
to hand against emergency. The following may be regardedas a representative
selection in caseef 6ssd;I I l0 volt, 500 watt projectorlamp.
I l6 volt, 3 watt pilot lamp.
I EF36 valve.
I CL33 valve.
I CY3l valve.
I CIC barretter.
I Take-upbelt.
HINTSON THE PRESENTATION
OF AN
EFFECTIVE
SHOW
Always, as far as possible, instal the projector at the. back of the auditorium
and avoid seating any of the audience behind the machine.
The auditorium should be darkened as much as possibleand in particular
stray light masked from the screen surface.
Before the audience is assembled, focus the picture on to the screen anrj
'allow an overlap of roughly half an inch all round the
black masking. Nothing
is more distracting'than having a picture smaller than the screen, with a consequeni bright frame round the picture,
The speaker should be placed beneath the screen, with its back removed.
It is,important to see that the front of the speaker case is not covered,otherwise
reproductionwill suffer accordingly. The best position for the speaker is slightly
above the headsof the audience, so that the sound will not be impeded.
C I e a n t h e a p e r t u r e p l a t e i f n e c e s s a r ya n d m a k e s u r e t h e p r o j e c t o r h a s b e e n
lubricated. Test for sound and ,picture before the audience assembles.
W h e n e v e r y t h i n g i s i r , r e a d i n e s s ,s t a r t t h e m o t o r a n d s w i t c h o n t h e p r o j e c t o r
l d ' m pa t t h e b e g i n n i n g o f t h e t i t l i n g . T u r n u p t h e v o l u m e c o n t r o l u n t i l s u f f i c i e n t
volume is obtained. Never increase the volume above the point necessary for
comfort. Adiust the tone control to the point of maximum intelligibility lf may
.r9
l
s
r
"
be advisableto alter the volume occasionally,but as far as possiblekeep the
tfir"a lat a constant level.
Towards the end of a reel switch off the projector lamp iust before the
blank trailer, to prevent showing a white screen.
'''
l'A gramophoneattachr.nentw-i1lpleasantlyfill-the interval whilstlfFie n-ext
Spoo!.ii being laced through the projector..
A proiectionist should always stand by his machine during a show, and
oqc.asionallycheck focus, volilme, etc. In the i,nterest<if the show the machine
s{4our.lldneverbe|efttocarryonwithout.supervision.
HEAD
S.l€r,Dep.rtment:
]MPER'IAL HOtTSE'
eo82,nEGeNt,sr,REer,
w'I
LQNDON,
Tqlcphon.::
REGcnt 7222
Telerams :
rGcBequip, Plccy, London
.
l
OFFIqE
-=ffi:
BG}q'0P,AABNTs
-r-
FILMHOUSE
WARDOURSTREET
L O N D O N. W . I
l6 mm. Service& Technical
D€ttartments;
wooDGER
FOAD,
SHEPHERD'SBUSH,
LONDON, W.I2
Telephone.rShepherd!sBurh 2050
!
Telegrams:
Soundifilm, Chisk, London
7'.A8