Table of Contents
Advertisement
Insert
no-hole tape in the
read
head, and apply down force on the
wires
with the
gram gage and
wire
tool to check
upper
contact pressure as shown in
Figure 14b.
Upper contact
pressure is increased
by lowering
the read
head
through
use
of the depth adjusting screw (28)
Figure
13,
and
the lever
eccentric (25).
After
contact
pressure has been adjusted
,
switch
timing
should
be verified with an
oscilloscope
per
the timing
diagram, Figure
8.
Check the
switch timing
of
18
channel
against
15
channel.
If
they
do
not coincide within the
7-14
millisecond range,
slightly
rotate the
fixed
contact
block.
When alternate hole, no-hole tape
is
positioned so the
star
wheel is sensing a
"no-hole" condition,
the two points in contact with the paper must be
equally
spaced from the
edges of
the
adjacent
holes as shown in Figure 15.
Figure
15.
Correct Positioning for Star Wheels
on
Alternate
Hole-No-Hole Tape
If
the
star
wheel
is
not symmetrically
located
between tape holes, contact
switching will occur early or late depending on direction
of
tape movement. Contact switching
should be checked on an oscilloscope by stepping the tape first forward and then in the reverse
direction.
If
the switching
in
both directions is not
within
the 7
7
14 millisecond zone, loosen
the recessed head
clamp
screw and turn the adjusting screw (25, Figure 6)
counter
clockwise
to advance the tape,
clockwise
to delay it. Tighten the
clamp screw
securely and recheck
switching as above.
•
The lift lever should be adjusted so the lifting stud passes over center with the
lever down firmly against the base plate.
If
adjustment
is
required, loosen the eccentric bolt,
and turn the
eccentric
(25, Figure 13) so the lever locks over
center.
CAUTION: Do not move the depth adjusting screw (28} for this screw adjusts
upper contact (N/ C)
pressure.
5. 3 Drive System Parts Replacement
To replace damaged gears or shafts, loosen all set
screws clamping
gears to
the shaft. Slide the shaft through its bearings. Take
care to
preserve
all
the shim washers
disassembled.
When re-assembling components, re-insert the
shaft
through its bearings, pick-
ing up
shim
washers,
gears,
or other
components
one at
a
time. Be
sure
to re-assemble
all
shim
washers in their proper places. This will usually keep shaft
end-play
and gear backlash
within the tolerances
shown
in Table 5. 3-1.
It
may become necessary to add or take away
shims when new gears are installed.
SEATTLE
Page 14
Advertisement
Table of Contents
