IBM 727 Manual Of Instruction page 28

Systems Sequence of
Operation
75.10. Q1 Full power to both
stop clutches.
04C Drop R2, rewind.
05C
Drop R3, R31, r e ­
wind.
04D Drop R5, R6,
start slow rewind,
and HD 7, time
delay.
75.10.02 Stop time delay
mtr.
06H Drop R13, clutch
transfer.
06B Drop retracting
solenoid latch.
011 Pick R33, r e ­
verse.
02J Manual reverse
line comes up.
Oil Pick R34, start.
02E Manual start line
com es up.
Tape moves in the reverse direction until the load point is sensed at the load-
point photo cell. As the tape passes under the load-point photo cell, the light is r e ­
flected to the cell. The cell output is a negative shift and is applied to an inverter
(75. 04). The output of this inverter is again inverted and pulls over a 20 ms SSrp.
The left output of this SST , nnot arriving at load point" goes down, dropping the
lower leg of AND circuit F27 (75. 05. 01).
tion and stops the tape with a reverse-stop status. At this same time, the right
Conditions
R4 pts.
"Caps out" microswitches
R2BL
R2AU
HD7 pt.
R3BU
R6AL
R 31-2n/c
R33-2
R33-1
R34-1
This puts the moving coil in the stop posi­
28
Remarks
Both capstans are fully
extended.
Time delay arm returns
to home position.
Vacuum column switches
now control reel clutches
(75.10.01). These
switches keep tape in the
center third of each co l­
umn from now on.
Energize the reverse
magnet. De-energize
the forward magnet.
Energize moving coil in
the start direction.