Print Mechanism - IBM Selectric Maintenance Manual

Excessive Band
Wi dth Between
o
(zero) and -1
-3 and +5
-3, +5 and 0 (zero)
-5 and -3
Cause
Incorrect balance
Incorrect rotate arm motion
Incorrect latch clearances
Incorrect paddle adjustment
Unwanted compensator roller droppage may result from
one or more of the following.
a. Improper detent timing
b. Malselection (popping latches)
c. Incorrect rotate spring tension or damper spring ten-
sion.
d. Binds in the typehead, upper ball socket, rotate
shaft, rotate pulley, or rotate spring.
e. Binds in the compensator or lever system.
f. Loose differential mounting bracket.
g. Excessive band width or head play.
If the band width appears to be all right but the align-
ment is not satisfactory, check the following items:
a.' Detent timing
b. Play or binds in the tilt or rotate detents. Side play
in the rotate detent can be checked by repeating any
full size character such as the letter" N" so that it
repeats for a full line. Move the carrier backman-
ually and repeat the operation without indexing. The
second line should cover the first line exactly. If
any of the characters are shadowed, side play in the
rotate detent could be the cause.
c. Loose fitting upper ball socket
Copy Control Lever
Copy Control
Ecc.
d. Excessive play in the carrier or rocker
e. Binds in the rocker parts
f.
If the -5 characters vary horizontally, improper
damper spring tension cou Id be the cause.
g. Improper ti It adjustments can cause poor horizontal
alignment by delaying the detent, seating.
NOTE: After the machine has been in use for some time
wear in the tape system will allow the typehead to drift
in the negative di recti on. It is not necessary to slip the
rotate shaft within the rotate pulley to REFINE the type-
head position. The proper position may be gained by re-
fining the eccentric stud adjustment. Be sure to RESEAT
the compensator roller after changing the eccentri c stud
adjustment. (Maintain the roller position 1/16" from the
top of the slot by adjustment of the rotate link.)
PRINT MECHANISM
1. Copy Control Lever - With the copy control lever de-
tented in the forward position, the high points of the
eccentrics should be vertical (Fig. 88). Adjust the copy
control lever on the shaft to satisfy this condition.
This adjustment provi des the most effective operation of
the eccentri cs in moving the platen forward and back.
NOTE: The stop ears on the copy control detent spri ng
should be formed to provide positive detenting in the
extreme front and rear positions of the lever.
CAUTION: The adjustment of the copy control lever,
while important as a preliminary setting, should not re-
quire adjustment unless it becomes loose or parts replace-
ment is necessary. Any change in the adjustment will
affect the front to rear position of the platen requiring
that other adjustments be altered to compensate.
FIGURE 88. Copy Control Mechanism
2-27