Ampex 351 Series - CONTROL CIRCUIT AND MAINTENANCE

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TAKE- UP MOTOR 8502 REW I ND MOTOR 8503
BRAKE TENS ION
ADJUSTMENT POINT
FOR LOW SIDE~
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CAPAC ITOR, MOT OR C51 2
3.75 MFD
BRAKE TENSION
AD JUS TMENT PO I NT S
F
OR H IGH SIDE
CAPACITOR , MOTOR
3.75 MFD
Tak e- up and r ew ind motor assemb lies
itself tightly aro u nd t he b rake drum as the
brake lever
end of the ban d moves to the r ight ,
increasing braking force. Wh
en the dr um is
rotating counterclockwise, the process is re-
versed,
ca us i ng the band to tend to pu ll away
from
the drum , decreasing the braking force.
The ratio
of the braking force in one direc-
tion to
th e braking force in the other - the
brake differe ntial - is approxi mate ly two to
one
on th is equipment.
Jn all mod es of operation, the greater brak-
ing force always
acts on the trailing turntable ,
ma
int a inin g the proper tape t ension as the sys-
tem is stoppe
d.
CONTROL CIRCUIT
(Refer to sch ematic di agram-Tape Transport
Control Circuit s)
Lo cate d in the co ntrol c ircuit box under-
neath
the tap e transport are all relays, th e ten-
sion
ad ju s tm e nt resistors, and electronic com-
ponents such as
the ca pa citors and resistors
shown in
th e foldout Hlustrntion, T ape Trans-
5-5
port Control Circuits, wi th th e exception of the
three motor starung capac it ors , the capsta n
solenoid, t
he brake solenoids and th e sa fety
microswitch
(w hic h arc mount ed adjacent to
th e assemb li es they serve).
On the outsi de of the control ci rcuil box
receptacles
are avail ab le for cables from the
drive motor, supply motor , take-up motor and
control cluster.
Fema le receptacles and plu gs
(
cab les n ot supplied) are also availab le for
interconnecti ng the tape transpo rt and acces-
sory
units such as remote control panels and a
pr ecision fr equency source when furnish e d.
NOTE
Th e special connecto r j11mper plngs
supplied for rece ptacl es J503S 60
CYCLE AMPLIFIER and ]502$ RE-
MOTE CONTROL must be plugged
into their r ecepta cl es whe n these ac-
cesso ry units are not used because
jumpe rs in th ese plugs cmnp lete th e
necessary ci.rcuits in the system for
proper operation.