Radio Shack TRS-80 Service Manual page 37
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Also See for TRS-80:
- Reference manual (274 pages) ,
- User manual (236 pages) ,
- Service manual (199 pages)
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A.
FUNCTION
The
Tractor Drive assembly supports
and
guides fan
fold,
tractor fed
paper
using
rear feed.
The
major
components
are
two
side
frames, guide
bars for driving
and
guiding the pin feed
tractors
and
two
pin
feed
tractors.
The two
pin
feed tractors
are
horizontally adjustable to
accept fan
fold
paper
from
4.5 inches (114.3
mm)
minimum
to
9
inches (228.6
mm)
maximum.
There
are
15
pins that project
from
the pin feed
tractor,
5
of
which always
mesh
with the
paper.
The
left
tractor unit also
contains the paper
empty
switch.
B.
REMOVAL/REPLACEMENT PROCEDURE
TOOLS
REQUIRED:
Phillips
Head
Screwdriver
1.
Tractor
Drive
Assembly
a.
Disconnect
the
paper
empty
switch connector,
J015,
from
connector P015.
b.
Remove
the
left
(2)
and
right (3)
stud screws,
two
flatwashers
(5)
and
two
nuts
(4)
that secure the tractor drive
assembly
to the tractor feed unit
(1).
c.
Remove
the
two
screws
(6),
lockwashers
(7)
and
flatwashers
(8)
and
remove
the
tractor drive
assembly
from
the
printer
frame.
2.
Pin
Feed
Tractors, Left
and
Right
a.
Remove
the
tractor drive
assembly
per
paragraph
3.13.B.1.
b.
Loosen
the set-screw
mounting
drive pulley
on
the
left
side
of the
tractor drive
assembly and
remove
the pulley
and
side plate.
c.
Slide
the
left
and
right
pin
feed
tractors off
of the
drive shaft
and
support
bar of the tractor
drive
assembly.
C.
ADJUSTMENTS
1.
Tractor Drive
Timing
Belt
Tension
(Figure
3-8D)
a.
Adjust
the tension of the
drive belt
so that
when
a
load
of 5
to
8 ounces
(
142
to
227
grams)
is
applied
at
the center
of the
belt,
the
belt
deflection
will
be
0.25
inches (6.35
mm).
2.
Paper
Travel (Figure 3-8E)
a.
Using the eccentric
knob on
the
right side
of the
tractor drive
assembly,
adjust the tractor units so that the plane
of
paper
travel
is
tangent
to the platen.
3.
Operator's
Adjustment
a.
Refer
to the
TRS-80
Line
Printer
Operator's
Manual
for instructions
on
loading
paper
into
the tractor
drive
assembly.
D.
PREVENTIVE
MAINTENANCE
1.
No
maintenance
is
required
on
the tractor
drive
assembly
or pin feed tractor
units.
3-21
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