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To allow installation of tape by the operator and also to provide freedom of move
ment during high-speed rewind, the upper plate is moved upward leaving a gap of
about 27/32 inch between the erase head and the read-write head assembly.
the time when tape is being transported through the machine for reading or writing,
the upper plate is down causing the assemblies to be in close contact with each other.
4 0 4. 1
Read-Write Head Assembly
The read-write head assembly contains the seven read-write heads in laminated
form , one behind the other.
down.
The entire head assembly is removable as a unit; connection to the read-write
coils is made through a multi-pin plug at the bottom.
should not be removed from the lower plate. It is set at the factory.
4 .4 .2
Erase Head
The erase head is located above and 3 /8 " to the left of the read-write head assem
bly.
It consists of one large coil and core covering the entire width of the tape. It
saturates all tracks in one direction during writing just ahead of the portion being
written on.
This process erases the information previously written.
kept very close to the read-write assembly vertically.
the right of the erase head to keep intimate contact between the tape and the read-
write head.
As previously stated, the erase head is mounted on the upper plate and moves
up during high-speed rewind time and when the machine is in an unload status.
4 .4 .3
Load Point Sensing
To indicate the beginning of the usable portion of the reel of tape, a small r e
flective spot is placed on the tape (plastic side).
placed on the front half of the tape width, 1/32" from the edge. It should be located
about ten feet from the physical end of the tape to allow sufficient wind-up on the ma
chine reel.
This reflective spot is sensed by a photo-electric pell arrangement shown in
Figure 9.
The light from the front bulb is reflected from the spot to the photo cell
directly to the right of it.
unit.
4 .4 .4
End-of-Tape Sensing
The end of the usable portion of the reel of tape is indicated by an identical r e
flective spot placed at least 14 feet from the physical end of the tape.
placed on the plastic side of the tape 1/32" from the back edge.
photo cell sense this reflective spot in the same manner that the load point is sensed.
4 .4 .5
Tape Brèak
During high-speed rewind, the machine should stop if the tape breaks. An in
dication of tape breakage is provided by directing a light source from the under side
of the tape to the end-of-tape photo cell.
The tape passes over the head assembly, oxide-side
This spot is 3 /1 6 " x 1" and is
This, in turn, operates control circuitry to stop the tape
Tape normally passes between the light
14
During
The read-write head assembly
The head is
A pressure pad is installed to
This spot is
The rear bulb and
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