Ampex 351 - Page 54

Control circuit box
6-6
Rewind
When REWIND button S507 is pressed,
rewind relay K504 is energized and held in this
condition by relay contact sets K504-1, K503-3
and the normally closed STOP button S502.
Contact set K504-2 connects the full a-c power
directly to the rewind (supply) motor, and
places R504 in the a-c circuit to the take-up
motor. The rewind motor thus operates at full
torque and the take-up motor at reduced torque,
and tape is pulled at a maximum speed from
5
st' o
Stop
When the tape is moving in any mode and
the STOP button (S502) is pressed, the brqke
solenoids and all relays are de-energized. The
brakes arc applied to both turntable motors.
The capstan drive motor will continue to
operate so long as the tape remains properly
threaded.
the take-up to the rewind reel. Contact set
K504-3 completes the d-c circuit to the brake
solenoids at each reel assembly, thus releasing
the brakes.
CAUTION
If the STOP and PLAY buttons are
pressed in too rapid a sequence when
the tape is in either fast winding
mode, tape will almost invariably be
broken or deformed. Always allow
All functional control of the tape transport,
with one exception, takes place at the control
circuit switch assembly comprising four push 
buttons: REWIND, FAST FORWARD, STOP
and PLAY. Two toggle switches REEL SIZE
and TAPE SPEED are mounted at cither end of
the control cluster. The exception is the RE 
CORD function which is controlled at the am 
plifier. The safety switch (not an operating
control) is mounted under the tape transport.
89-0131
89-0144
Issue A
Fast Forward
When FAST FORWARD button S506 is
pressed, fast forward relay K503 is energized
and held through contacts K503-1, K504-3 and
the normally closed STOP button S502. Con 
tact set K503-2 connects the full a-c power to
the take-up motor, and places R504 in the cir 
cuit to the rewind motor. The take-up motor
now operates at full torque and the rewind
motor at reduced torque, causing the tape to
be pulled at a maximum speed from the re 
wind to the take-up reel.
if
Iso
4
r
Safety Interlocks
When the tape is moving in either of the
high speed modes (fast forward or rewind)
it is impossible to switch to the play mode
without first pushing the STOP button. In fast
forward, contact K503-1 interlocks the play
relay and capstan solenoid. In rewind, K504-3
is the interlock.
NOTE
The record mode is not a tape motion
control function, but it is interlocked
and dependent on the PLAY button,
which must be pressed before the
record mode can be energized at the
amplifier.
Play
When PLAY button S505 is pressed, play
relay K502 is energized. Capstan solenoid K501
is energized through K502-1. Contact sets
K502-1, K503-1, K504-3, and the normally
closed STOP button S502 form a holding cir 
cuit. Power is connected to the turntable reel
motors through contact K502-2. Through con 
tact K502-3, D.C. voltage is applied to the
brake solenoids K505 and K506. The rec!
motors are powered and the brakes arc re 
leased simultaneously, causing the equipment
to operate in the reproduce mode at the speed
selected by TAPE SPEED SWITCH S503.