IBM Selectric Service Manual

28.0 SELECTRIC I/o SPECIFICATIONS
28.1 Magnets and Solenoids
Component
Maxim'um
Pick Time
Ribbon
Shift Magnet
All Other Magnets
28.2 Clutch Operating Speed
ms.
12 ms.
10 ms.
Mechanism
Max. Mechanical Delay
Pri nt Cyc Ie Clutch
Operational Cycle Clutch
Shift Clutch
29.0 Selectric I/O Modes of Operation
29.1 Closed Loop
10 ms.
14 ms.
7 ms.
Character rate is under control of I/O feedback sig-
nals. A character wi II not be sent to the I/O unti I
feedback contacts have signa lied that the previous
cycle is almost complete and the printer is ready for
another character.
29.2 Open Ended
In the open ended mode of operation, the character
rate is fixed, independent of I/O feedback signa Is.
This rate is usually set at 14.8 characters per second,
or a character every 67.5 ms.
The
Selectric I/O has the capabi lity of running wide
open at the rate of 15.5 characters per second, or a
character every 64.5 ms. This 3 mi IIi second differ-
ence is the safety factor allowed in the event of a
s
low printer cyc Ie.
30.0 OSCILLOSCOPE INTERPRETATIONS
The following osci lIoscope trace pictures wi II cover
every area of the Se lectri c I/O Pri nter. Wherever
scoping
is necessary refer to these photos for compar-
ative ana lysis.
PRINT MAGNET R2A (ONE ARMATURE PICKED)
Figure 30.0
Scope:
Mag Common
R2A Test Jack
5 ms/cm
o
LSA Function: Print Space
Ref.
Ti It & Rotate: T3/ R+3
Time Base:
Vert Amp: 2
volt/cm
Sync:
+
Int
Time from start of pick to C2 N/C opens 25.0 ms
Magnet seal time 6.0 ms
C2 N/C opens at 35 0 = 12.5 ms
18.5 ms
Total Mechanical Delay
6.5 ms
PRINT MAGNET R2A (ALL ARMATURES PICKED)
4-32
Figure 30.1
Scope:
Ref.
Time Base:
Vert Amp:
Sync:
Mag Common
R2A Test Jack
5 ms/cm
2
volt/cm
+ Int
o LSA Function: Print Space
Ti It & Rotate: TO R-5
Time from start
of pick to C2 N/C opens
Magnet seal time
5.0 ms
12.5 ms
26.0 ms
C2 N/C opens at 35
0
=
17.5 ms
Total Mechanical Delay 8.5 ms

IBM Selectric Specifications

General

Type	Electric typewriter
Introduced	1961
Keyboard Layout	QWERTY
Carriage Return	Electric
Manufacturer	IBM
Printing Technology	Typeball (golf ball)
Power Source	AC Power
Power Supply	120V AC