IBM 727 Manual Of Instruction page 5

THE text and illustrations in this manual have been prepared
for teaching purposes and as an aid for learning the 727 Tape
Drive and the Tape Drive Tester. All material was prepared
from information relative to production at a given level.
gineering changes may alter logic and machine functions.
course, these engineering changes could cause the machine' s
production to be at a different level from that described by this
manual. Therefore, the use of this manual as a reference is
subject to changes in the machine.
One change should be made in the Type 727 Magnetic Tape
Unit Systems book accompanying this write-up for the systems
and write-up to be at the same level, logically.
should be made on systems page 75.10. 01 as follows:
1. Remove 12 AU and the lk-ohm potentiometer and 500-
ohm resistor tied to the 12 AUn/o point.
2. Add a jumper from 12 AUn/c to terminal 3.
Doing this removes 12 AUn/o and shortens 12 AUn/c.
chines in the field should already have been changed.
ABBREVIATIONS
The following abbreviations are used throughout this manual.
caps.
EOT
EMF
go-fb
LP
L .P .
LT
LRCC
usee
ms
mtr.
mv
MV
NRZI
pt.
PU
R/W
sel
SS
TDT
TI
TU
tgr.
NOTICE
This change
capstans
end of tape
electro motive force
go/forward-backward
latch pick
load point
latch trip
longitudinal redundancy check character
microsecond
millisecond
motor
millivolt
multivibrator
non return to zero
point
pick up
read-write
select
single shot
tape drive tester
tape indicator
tape unit
trigger
En­
Of
Ma­